Phase Ib study of talimogene laherparepvec in combination with atezolizumab in patients with triple negative breast cancer and colorectal cancer with liver metastases

BACKGROUND

Talimogene laherparepvec (T-VEC), a first-in-class oncolytic viral immunotherapy, enhances tumor-specific immune activation. T-VEC combined with atezolizumab, which blocks inhibitor T-cell checkpoints, could provide greater benefit than either agent alone. Safety/efficacy of the combination was explored in patients with triple negative breast cancer (TNBC) or colorectal cancer (CRC) with liver metastases.

METHODS

In this phase Ib, multicenter, open-label, parallel cohort study of adults with TNBC or CRC with liver metastases, T-VEC (10⁶ then 10⁸ PFU/ml; ≤4 ml) was administered into hepatic lesions via image-guided injection every 21 (±3) days. Atezolizumab 1200 mg was given on day 1 and every 21 (±3) days thereafter. Treatment continued until patients experienced dose-limiting toxicity (DLT), had complete response, progressive disease, needed alternative anticancer treatment, or withdrew due to an adverse event (AE). The primary endpoint was DLT incidence, and secondary endpoints included efficacy and AEs.

RESULTS

Between 19 March 2018 and 6 November 2020, 11 patients with TNBC were enrolled (safety analysis set: n = 10); between 19 March 2018 and 16 October 2019, 25 patients with CRC were enrolled (safety analysis set: n = 24). For the 5 patients in the TNBC DLT analysis set, no patient had DLT; for the 18 patients in the CRC DLT analysis set, 3 (17%) had DLT, all serious AEs. AEs were reported by 9 (90%) TNBC and 23 (96%) CRC patients, the majority with grade ≥3 [TNBC, 7 (70%); CRC, 13 (54%)], and 1 was fatal [CRC, 1 (4%)]. Evidence of efficacy was limited. Overall response rate was 10% (95% confidence interval 0.3-44.5) for TNBC; one (10%) patient had a partial response. For CRC, no patients had a response; 14 (58%) were unassessable.

CONCLUSIONS

The safety profile reflected known risks with T-VEC including risks of intrahepatic injection; no unexpected safety findings from addition of atezolizumab to T-VEC were observed. Limited evidence of antitumor activity was observed.

Risk-adapted modulation through de-intensification of cancer treatments: an ESMO classification

BACKGROUND

The landscape of clinical trials testing risk-adapted modulations of cancer treatments is complex. Multiple trial designs, endpoints, and thresholds for non-inferiority have been used; however, no consensus or convention has ever been agreed to categorise biomarkers useful to inform the treatment intensity modulation of cancer treatments.

METHODS

An expert subgroup under the European Society for Medical Oncology (ESMO) Precision Medicine Working Group shaped an international collaborative project to develop a classification system for biomarkers used in the cancer treatment de-intensification, based on a tiered approach. A group of disease-oriented clinical, translational, methodology and public health experts, and patients' representatives provided an analysis of the status quo, and scanned the horizon of ongoing clinical trials. The classification was developed through multiple rounds of expert revisions and inputs.

RESULTS

The working group agreed on a univocal definition of treatment de-intensification. Evidence of reduction in the dose-density, intensity, or cumulative dose, including intermittent schedules or shorter treatment duration or deletion of segment(s) of the standard regimens, compound(s), or treatment modality must be demonstrated, to define a treatment de-intensification. De-intensified regimens must also portend a positive impact on toxicity, quality of life, health system burden, or financial toxicity. ESMO classification categorises the biomarkers for treatment modulation in three tiers, based on the level of evidence. Tier A includes biomarkers validated in prospective, randomised, non-inferiority clinical trials. The working group agreed that in non-inferiority clinical trials, boundaries are highly dependent upon the disease scenario and endpoint being studied and that the absolute differences in the outcomes are the most relevant measures, rather than relative differences. Biomarkers tested in single-arm studies with a threshold of non-inferiority are classified as Tier B. Tier C is when the validation occurs in prospective-retrospective quality cohort investigations.

CONCLUSIONS

ESMO classification for the risk-guided intensity modulation of cancer treatments provides a set of evidence-based criteria to categorise biomarkers deemed to inform de-intensification of cancer treatments, in risk-defined patients. The classification aims at harmonising definitions on this matter, therefore offering a common language for all the relevant stakeholders, including clinicians, patients, decision-makers, and for clinical trials.

Sacituzumab govitecan, a Trop-2-directed antibody-drug conjugate, for patients with epithelial cancer: final safety and efficacy results from the phase I/II IMMU-132-01 basket trial

BACKGROUND

Sacituzumab govitecan (SG), a trophoblast cell surface antigen-2 (Trop-2)-directed antibody-drug conjugate, has demonstrated antitumor efficacy and acceptable tolerability in a phase I/II multicenter trial (NCT01631552) in patients with advanced epithelial cancers. This report summarizes the safety data from the overall safety population (OSP) and efficacy data, including additional disease cohorts not published previously.

PATIENTS AND METHODS

Patients with refractory metastatic epithelial cancers received intravenous SG (8, 10, 12, or 18 mg/kg) on days 1 and 8 of 21-day cycles until disease progression or unacceptable toxicity. Endpoints for the OSP included safety and pharmacokinetic parameters with investigator-evaluated objective response rate (ORR per RECIST 1.1), duration of response, clinical benefit rate, progression-free survival, and overall survival evaluated for cohorts (n > 10 patients) of small-cell lung, colorectal, esophageal, endometrial, pancreatic ductal adenocarcinoma, and castrate-resistant prostate cancer.

RESULTS

In the OSP (n = 495, median age 61 years, 68% female; UGT1A1∗28 homozygous, n = 46; 9.3%), 41 (8.3%) permanently discontinued treatment due to adverse events (AEs). Most common treatment-related AEs were nausea (62.6%), diarrhea (56.2%), fatigue (48.3%), alopecia (40.4%), and neutropenia (57.8%). Most common treatment-related serious AEs (n = 75; 15.2%) were febrile neutropenia (4.0%) and diarrhea (2.8%). Grade ≥3 neutropenia and febrile neutropenia occurred in 42.4% and 5.3% of patients, respectively. Neutropenia (all grades) was numerically more frequent in UGT1A1∗28 homozygotes (28/46; 60.9%) than heterozygotes (69/180; 38.3%) or UGT1A1∗1 wild type (59/177; 33.3%). There was one treatment-related death due to an AE of aspiration pneumonia. Partial responses were seen in endometrial cancer (4/18, 22.2% ORR) and small-cell lung cancer (11/62, 17.7% ORR), and one castrate-resistant prostate cancer patient had a complete response (n = 1/11; 9.1% ORR).

CONCLUSIONS

SG demonstrated a toxicity profile consistent with previous published reports. Efficacy was seen in several cancer cohorts, which validates Trop-2 as a broad target in solid tumors.

Abstract SP012: Convergent evolution of resistance pathways during early stage breast cancer treatment with combination cell cycle (CDK) and endocrine signaling inhibitors

Combining cyclin-dependent kinase (CDK) inhibitors with endocrine therapy improves outcomes for metastatic estrogen receptor positive (ER+), HER2 negative, breast cancer patients. However, the value of this combination in potentially curable earlier stage patients is not clear. Using single cell transcriptomic profiling, we examined the evolutionary trajectories of early stage breast cancer tumors using serial tumor biopsies from a clinical trial of preoperative endocrine therapy alone (letrozole) or in combination with the cell cycle inhibitor ribociclib. Applying hierarchical regression and Gaussian process mathematical modelling, we classified each tumor by whether it shrinks or persists with therapy and determined cancer phenotypes related to evolution of resistance and cell cycle transcriptional rewiring. We found that all patients’ tumors undergo subclonal evolution during therapy, irrespective of the clinical response. However, tumors subjected to endocrine therapy alone showed reduced diversity over time, those facing combination therapy exhibited increased diversity. Despite different diversity, single nuclei RNA sequencing uncovered common phenotypic changes in tumor cells that persist following treatment. In these tumors, accelerated loss of estrogen signaling is convergent with up-regulation of the JNK pathway, while persistent tumors that maintain estrogen signaling during therapy show potentiation of CDK4/6 activation consistent with ERBB4 and ERK signaling up-regulation. Cell cycle reconstruction identified that these tumors can rebound during combination therapy treatment, indicating stronger selection and promotion of a proliferative state. These results indicate that combination therapy in early stage ER+ breast cancers with ER and CDK inhibition drives rapid evolution of resistance via a shift from estrogen signaling to alternative growth factor receptor mediated proliferation and JNK signaling activation, concordant with a bypass in the G1 checkpoint.

Citation Format: JI Griffiths, J Chen, PA Cosgrove, A O'Dea, P Sharma, CX Ma, M Trivedi, K Kalinsky, KB Wisinski, R O'Reagan, I Makhoul, LM Spring, A Bardia, FR Adler, AL Cohen, JT Chang, QJ Khan, AH Bild. Convergent evolution of resistance pathways during early stage breast cancer treatment with combination cell cycle (CDK) and endocrine signaling inhibitors [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP012.

Sacituzumab govitecan in previously treated hormone receptor-positive/HER2-negative metastatic breast cancer: final results from a phase I/II, single-arm, basket trial

BACKGROUND

Trophoblast cell-surface antigen-2 (Trop-2) is expressed in epithelial cancers, including hormone receptor-positive (HR+) metastatic breast cancer (mBC). Sacituzumab govitecan (SG; Trodelvy®) is an antibody-drug conjugate composed of a humanized anti-Trop-2 monoclonal antibody coupled to SN-38 at a high drug-to-antibody ratio via a unique hydrolyzable linker that delivers SN-38 intracellularly and in the tumor microenvironment. SG was granted accelerated FDA approval for metastatic triple-negative BC treatment in April 2020.

PATIENTS AND METHODS

We analyzed a prespecified subpopulation of patients with HR+/human epidermal growth factor receptor 2-negative (HER2-) HR+/HER2- mBC from the phase I/II, single-arm trial (NCT01631552), who received intravenous SG (10 mg/kg) and whose disease progressed on endocrine-based therapy and at least one prior chemotherapy for mBC. End points included objective response rate (ORR; RECIST version 1.1) assessed locally, duration of response (DOR), clinical benefit rate, progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Fifty-four women were enrolled between 13 February 2015 and 1 June 2017. Median (range) age was 54 (33-79) years and all received at least two prior lines of therapy for mBC. At data cut-off (1 March 2019), 12 patients were still alive. Key grade ≥3 treatment-related toxicities included neutropenia (50.0%), anemia (11.1%), and diarrhea (7.4%). Two patients discontinued treatment due to treatment-related adverse events. No treatment-related deaths occurred. At a median follow-up of 11.5 months, the ORR was 31.5% [95% confidence interval (CI), 19.5%-45.6%; 17 partial responses]; median DOR was 8.7 months (95% CI 3.7-12.7), median PFS was 5.5 months (95% CI 3.6-7.6), and median OS was 12 months (95% CI 9.0-18.2).

CONCLUSIONS

SG shows encouraging activity in patients with pretreated HR+/HER2- mBC and a predictable, manageable safety profile. Further evaluation in a randomized phase III trial (TROPiCS-02) is ongoing (NCT03901339).

TRIAL REGISTRATION

ClinicalTrials.gov NCT01631552; https://clinicaltrials.gov/ct2/show/NCT01631552.

Sacituzumab govitecan: antibody-drug conjugate in triple-negative breast cancer and other solid tumors

Patients with metastatic triple-negative breast cancer (mTNBC) that has progressed on first-line therapy have a poor prognosis with limited therapeutic options. Sacituzumab govitecan (SG) is a novel antibody-drug conjugate (ADC) that has shown promising efficacy in mTNBC. SG is comprised of SN-38, the active metabolite of irinotecan, conjugated via a hydrolyzable linker to the humanized RS7 antibody targeting trophoblast cell surface antigen 2 (Trop-2), a glycoprotein that is expressed at high levels in many epithelial solid tumors. It has received breakthrough therapy status by the U.S. Food and Drug Administration (FDA) for the treatment of patients with pretreated mTNBC. In this review, we summarize available data regarding the pharmacology, pharmacokinetics, safety and efficacy of SG and describe ongoing and future clinical studies investigating this agent.

Abstract P1-20-02: Incidence of hyperglycemia in non-diabetic patients with early-stage breast cancer treated with chemotherapy

Background: There are shared risk factors between breast cancer (BC) and diabetes mellitus (DM). BC treatments including chemotherapy given in combination with glucocorticoids can induce hyperglycemia and steroid related DM. Patients with DM are at increased risk of developing chemotherapy related toxicities such as chemotherapy induced peripheral neuropathy (CIPN) compared to those without DM. The incidence of hyperglycemia during chemotherapy in non-diabetic patients with early-stage breast cancer is unknown.

Methods: We performed a retrospective analysis of non-diabetic women with stage I-III breast cancer treated with chemotherapy at Columbia University Medical Center from 9/1/2016-8/31/2017 to evaluate hyperglycemia incidence during chemotherapy and up to six months after chemotherapy completion. Eligible patients were identified in the electronic health record (EHR) by ICD9 and 10 codes (ICD9 174.x and ICD10 C50.x) and a record of chemotherapy administration. Non-diabetic patients were defined by chart review as no recorded history of diabetes and no receipt of a diabetes medication in the EHR. Breast cancer stage was determined by chart review. Glucose values were recorded prior to chemotherapy, during chemotherapy, and for six-months after chemotherapy completion. We defined hyperglycemia as a glucose value of ≥200 mg/dl. Median time to hyperglycemia was also calculated.

Results: We identified 82 eligible patients. The majority of patients received dexamethasone during their chemotherapy course (79 patients, 96.3%). The most frequent chemotherapy regimen was doxorubicin/cyclophosphamide and paclitaxel (32 patients, 39.0%). At baseline, 20 patients (24.4%) had a normal body mass index (BMI), 27 patients (32.9%) were overweight, and 31 patients (37.8%) were obese. Hyperglycemia occurred in 8 patients (9.8%) after initiation of chemotherapy. Among patients with hyperglycemia, the maximum blood glucose was between 200-299 mg/dl in seven patients (87.5%), and between 500-599 in one patient (12.5%). The median time to hyperglycemia was 84 days. Among patients who did not experience hyperglycemia, the maximum blood glucose was between 140-159 mg/dl in six patients (8.1%), between 160-179 mg/dl in eight patients (10.8%), and between 180-199 mg/dl in three patients (4.1%). Three patients were diagnosed with DM following chemotherapy completion.

Conclusion: Hyperglycemia occurred in almost 10% of non-diabetic patients who received chemotherapy for early-stage breast cancer. Additionally, over 30% of patients had a blood glucose of 140 mg/dl or higher after chemotherapy initiation. The impact of hyperglycemia on the development of chemotherapy related toxicities in this group is unknown. Future research is needed to identify effective interventions for glucose control during chemotherapy, and to determine if glucose control during treatment can reduce the risk of chemotherapy related toxicities, specifically CIPN.

Citation Format: Accordino MK, Lin A, Wright JD, Trivedi MS, Kalinsky K, Crew KD, Hershman DL. Incidence of hyperglycemia in non-diabetic patients with early-stage breast cancer treated with chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-20-02.

Abstract P6-18-35: A phase 1 study of erlotinib and metformin in advanced triple negative breast cancer

Background: The epidermal growth factor receptor (EGFR) is frequently overexpressed in triple negative breast cancer (TNBC). However, EGFR inhibitors have not shown efficacy as monotherapy in TNBC. One strategy for overcoming resistance to EGFR inhibition is concomitant inhibition of downstream signaling. Metformin is a LKB1-dependent AMPK activator that inhibits both MAPK and AKT signaling. The combination of the EGFR inhibitor erlotinib and metformin synergistically induces apoptosis in TNBC cell lines and decreases tumor burden in PTEN-null EGFR-amplified mouse xenograft models. We evaluated the combination of erlotinib and metformin in a phase 1 study of patients with advanced TNBC.

Methods: Patients with advanced TNBC who had received at least one prior line of therapy for metastatic disease were eligible. Erlotinib dose was fixed at 150mg daily. Metformin dose escalation was planned according to a 3+3 design, beginning at 850mg BID and escalating to 850mg TID. One de-escalation to 500mg BID was allowed. Dose-limiting toxicities (DLT) were assessed during the first five weeks of therapy. The primary objectives were to determine the maximum tolerated dose (MTD) of metformin with fixed dose erlotinib and to determine the potential for clinical benefit. Secondary endpoints were response rate, stable disease rate, and progression free survival. Pre- and on-treatment skin biopsies were collected to determine the effect of the study drugs on their respective cell signaling targets, particularly EGFR, AMPK, and mTOR.

Results: Between March 2013 and May 2015, nine patients were screened and eight were enrolled. Median age was 48 years (range 37-79). Median number of prior therapies for metastatic disease was 2.5 (range 1-6). No DLT events were reported in either of the dose escalation cohorts during the DLT assessment period. AEs occurring in three or more patients and all grade III AEs are reported in Table 1. Grade III diarrhea despite maximum supportive care required dose reduction of metformin from 850mg TID to 850mg BID in one patient. Grade III rash led to study withdrawal in one patient. No grade IV AEs were reported. Per RECIST v1.1, the best observed response was stable disease in two patients (25%). Median time on study was 2.0 months (range 1.2-3.0). Skin biopsy marker assessment is ongoing and will be reported.

Conclusion: The combination of erlotinib and metformin was generally well tolerated in a population of pre-treated metastatic TNBC patients. No unexpected toxicities occurred. While no responses were achieved, stable disease was observed in patients who received this non-chemotherapy combination.

Adverse EventsEventMetformin 850mg BID n=3Metformin 850mg TID n=5All patients n=8 Number of patients (percent) All gradesGrade IIIAll gradesGrade IIIAll gradesGrade IIIRash3 (100)1 (33.3)5 (100)08 (100)1 (12.5)Diarrhea3 (100)05 (100)2 (40.0)8 (100)2 (25.0)Weight loss1 (33.3)05 (100)06 (75.0)0Dry skin1 (33.3)05 (100)06 (75.0)0Nausea2 (66.7)03 (60.0)05 (62.5)0Vomiting1 (33.3)03 (60.0)04 (50.0)0Dry mouth1 (33.3)03 (60.0)04 (50.0)0Dysgeusia1 (33.3)02 (40.0)03 (37.5)0Increased creatinine2 (66.7)01 (20.0)03 (37.5)0Fatigue1 (33.3)02 (40.0)03 (37.5)0Anorexia1 (33.3)02 (40.0)03 (37.5)0Hyponatremia1 (33.3)1 (33.3)001 (12.5)1 (12.5)

Citation Format: Fenn KM, Maurer MA, Lee SM, Crew KD, Trivedi MS, Accordino MK, Hershman DL, Kalinsky K. A phase 1 study of erlotinib and metformin in advanced triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-35.

Abstract P2-11-01: Safety and efficacy of sacituzumab govitecan (anti-Trop-2-SN-38 antibody-drug conjugate) as ≥3rd-line therapeutic option for treatment-refractory HER2-negative metastatic breast cancer (HER2Neg mBC)

Background: Sacituzumab govitecan is an antibody-drug conjugate consisting of SN-38, the active metabolite of irinotecan, conjugated to a humanized mAb targeting Trop-2 (trophoblastic antigen-2), which is highly expressed in many epithelial cancers. A phase I/II basket trial (NCT01631552) investigated its activity in patients (pts) with advanced epithelial cancers. Herein, we summarize pooled safety and efficacy findings in 162 pts with HER2-negative metastatic breast cancer (mBC) accrued between 7/2013 and 6/2017 who received at least 2 prior therapies for metastatic disease and were treated with sacituzumab govitecan at the 10 mg/kg dose level.

Methods: Patients with triple-negative (N=108) and patients with hormone-receptor positive (N=54) mBC received 10 mg/kg sacituzumab govitecan on days 1 & 8 of a 21-day cycle continued until progression or unacceptable toxicity. All pts had measurable disease by CT or MRI. Efficacy was assessed locally by RECIST 1.1 including overall response rate (ORR) and Kaplan-Meier estimates of duration of response (DOR), progression-free survival (PFS) and overall survival (OS). Adverse events (AE) were evaluated according to CTCAE v4.0

Results: The patient cohort (161 female /1 male; median age 55 yrs, range 31-80) received a median of 4 prior therapies for metastatic disease (range 2-17), with prior chemotherapy agents in the metastatic setting including taxane (68%), capecitabine (60%), platinum (59%), gemcitabine (44%), eribulin (41%), and anthracycline (38%). 77 pts have died, with 57 in long-term follow-up and 28 still on treatment at data cutoff. The median number of administered sacituzumab govitecan doses was 14 (range 1-88). Treatment was generally well tolerated. 29% of pts had dose reductions, 3% discontinued treatment due to drug-related AEs, and there were no treatment-related deaths. Based on currently available AE data, grade ≥ 3 toxicity included neutropenia (43%), anemia (9.5%), diarrhea (7.0%) and febrile neutropenia (6.3%). For the TNBC subgroup, with a median follow-up of 9.3 months, the ORR was 33% (3 CRs + 33 PRs /108) with a median DOR of 8.3 months (95% CI: 4.8 – 11.6). For the ER+ subgroup, with a median follow-up of 10.0 months, the ORR was 31% (17 PRs/54) with a median DOR of 7.4 months (95% CI: 4.4 – 18.3). The combined HER2Neg ORR was 33% (3 CRs+50 PRs/162), with a median DOR of 8.3 months (95% CI: 4.9 - 10.8), PFS of 5.6 months (95% CI: 5.1 – 6.9) and OS of 13.0 months (95% CI: 11.5 - 15.0). The ORR was comparable for pts ≤ 50 yrs. old [32.2% (19/59)] vs. > 50 yrs old [33.0% (34/103)] and little different for pts with 2 prior therapies [35.4% (17/48)] vs. >2 prior therapies [31.6% (36/114)].

Conclusions: Monotherapy with sacituzumab govitecan was well tolerated with a manageable safety profile, and achieved a 30+% objective response rate among heavily pre-treated patients with HER2-negative metastatic breast cancer regardless of ER status.

Citation Format: Kalinsky K, Isakoff SJ, Tolaney SM, Juric D, Mayer IA, Vahdat LT, Diamond JR, O'Shaughnessy J, Moroose RL, Santin AD, Shah NC, Abramson V, Goldenberg DM, Sharkey RM, Washkowitz SA, Wegener WA, Iannone R, Bardia A. Safety and efficacy of sacituzumab govitecan (anti-Trop-2-SN-38 antibody-drug conjugate) as ≥3rd-line therapeutic option for treatment-refractory HER2-negative metastatic breast cancer (HER2Neg mBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-11-01.

Abstract P2-03-01: Akt inhibition associated with change in immunophenotype of tumor microenvironment (TME) in breast cancer (BC)

Background: The PI3K/Akt/mTOR pathway is a known oncogenic pathway in BC. In addition, this pathway has demonstrated capacity to modulate host immune activity and may indirectly affect tumorigenesis. Clinicopathologic studies have demonstrated that lymphocyte density within the TME is predictive of chemosensitivity and improved prognosis in BC, while myeloid infiltration may play a deleterious role. To define the impact of Akt inhibition on the TME, we analyzed tumor tissue from patients (pts) with early-stage BC treated with single agent MK-2206, an Akt inhibitor, enrolled on a presurgical trial (NCT01319539).

Methods: Quantitative immunofluorescence (qmIF) was performed for CD3, CD8, CD4, FOXP3, CD68, Pancytokeratin on 4uM sections from biopsy and surgical specimens of MK-2206 (n=5) and control (n=5) pts. Images were analyzed using Vectra/inForm software (PerkinElmer), allowing for multiparameter phenotyping. Transcriptomic analysis was performed on surgical specimens to assess if differences exist in mRNA expression of tumor-associated and immune genes between pts treated with MK-2206 (n=5) and untreated matched controls (n=5) (nanoString). Statistical analysis was performed using t-Test, NetBID, and multiple comparison analysis by Benjamini-Hochberg. Gene set enrichment analysis (GSEA) was performed within R with gene sets from Molecular Signatures Database (Hallmark, Reactome, GO).

Results: On qmIF analysis, MK-2206 treated pts exhibited a significant increase in median cytotoxic T-cell (CD3+CD8+, CTL) density between pretreatment biopsy and surgical excision specimens, as compared to the control pts (87% vs.0.2%, p < 0.05). Mean macrophage density (CD68+) was numerically lower in surgical specimens of pts who received MK-2206 vs. control pts, although CD68+ infiltration was overall low (p=ns). mRNA expression supports in vivo activity of MK-2206 with lower expression levels of cell cycle, proliferation and anti-apoptotic genes (e.g. CTNNB1, CCND2, BAX) and greater expression of pro-apoptotic genes (e.g. BAD) associated with MK-2206 treatment (raw p-value <0.05). Additionally, greater mRNA copy number of IGF1R, a receptor tyrosine kinase (RTK) previously identified as upregulated in BC in the context of Akt inhibition, was found in post-MK-2206 surgical specimens as compared to control, non-MK-2206 specimens (raw p-value <0.05). MK-2206 was also associated with reduced expression of myeloid markers (e.g. CSF1R, CD163) (raw p-value <0.05). By GSEA, canonical gene sets related to interferon signaling were increased in post-MK-2206 specimens as compared to non-MK-2206 specimens, whereas monocyte chemotaxis genes were decreased in treated pts (adj p-value <0.05). RT-PCR is currently underway to compare biopsy and surgical specimens for a subset of RTK, immune and apoptosis related genes identified above.

Conclusion: mRNA and qmIF analysis suggest that Akt inhibition, may increase interferon signaling, CTL density, and decrease myeloid infiltration. Thus, Akt inhibition may promote a favorable TME. At present, there are both FDA approved and investigational agents that target the PI3K/mTOR pathway. Further investigation is warranted to understand the impact of Akt inhibition on the TME and potential therapeutic implications.

Citation Format: Marks DK, Gartrell RD, Pan Q, El Asmar M, Hart TD, Esancy CL, Lu Y, Yu J, Hibshoosh H, Connolly E, Kalinsky K, Saenger YM. Akt inhibition associated with change in immunophenotype of tumor microenvironment (TME) in breast cancer (BC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-03-01.

Abstract P6-18-31: PROCLAIM-CX-072: Monotherapy for advanced triple negative breast cancer with skin metastases in a phase 1-2 trial of the PD-L1 probody therapeutic CX-072

Background: Probody™ therapeutics are novel, fully recombinant antibody prodrugs designed to remain relatively inactive in healthy tissue and to be specifically activated by proteases in the tumor microenvironment. In this way, Probody therapeutics may broaden the therapeutic window for effective but potentially toxic anticancer agents. CX-072 is a Probody therapeutic directed against programmed death-ligand 1 (PD-L1) for the treatment of cancer patients. In a first-in-human, open-label, multicenter, dose-escalation, 3+3 design, phase 1-2 study, PROCLAIM-CX-072 (PRObody CLinical Assessment In Man) (NCT03013491), 22 patients were enrolled in the phase 1 dose escalation portion. Twenty patients were evaluable per RECIST v1.1. Three patients had confirmed partial response (15%), including a 39-year-old woman with stage IV triple negative breast cancer (TNBC) treated with 10 mg/kg CX-072 monotherapy whose disease had progressed on one previous line of chemotherapy for metastatic disease. Metastatic sites included extensive nodal disease and skin/chest wall lesions. The tumor was negative for PD-L1 expression, was microsatellite stable, and had a low tumor mutational burden (4 mutations/megabase). Positive results from the phase 1 study suggest that additional exploration of treatment with CX-072 monotherapy in the TNBC patient population is warranted.

Dose expansion trial design: The phase 2 dose expansion part of the PROCLAIM-CX-072 study will include enrollment of TNBC patients with skin metastases. Key inclusion criteria for patients in the TNBC cohort are as follows: naive to immunotherapy (PD-1/PD-L1 and CTLA-4 inhibitors), approved immune checkpoint inhibitor agents not available, histologically confirmed triple negative (estrogen receptor–, progesterone receptor–, and human epidermal growth factor receptor-2–negative cancer per ASCO-CAP guidelines), previously treated with 1 to 3 systemic chemotherapy regimens, and locally advanced and recurrent skin or subcutaneous metastases not suitable for surgical resection or radiotherapy. Patients will receive doses of 10 mg/kg CX-072 intravenously every 2 weeks. Efficacy will be evaluated using RECIST v1.1 and immune-related RECIST criteria. Safety and tolerability will be assessed based on the incidence and severity of adverse events (categorized by NCI CTCAE criteria, v4.03) and relationship to study drug. Other analyses will include pharmacokinetics, incidence of anti-drug antibodies against CX-072, exploratory analysis for immune response, and CX-072 activation in the tumor.

PROBODY is a trademark of CytomX Therapeutics, Inc.

Citation Format: Adams S, Hamilton E, Ott PA, Cho D, Kalinsky K, LoRusso P, Will M, Huels V, Benson B, Murias C, Arkenau H-T. PROCLAIM-CX-072: Monotherapy for advanced triple negative breast cancer with skin metastases in a phase 1-2 trial of the PD-L1 probody therapeutic CX-072 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-31.

Abstract PD6-10: Association between adherence to cardiovascular medications and cardiovascular events following a diagnosis of early stage breast cancer

Background: Studies show that patients diagnosed with early-stage breast cancer (BC) are more likely to die from cardiovascular disease (CVD) than BC. Adherence to CVD medications, such as statins and antihypertensives, is poor in BC survivors, particularly in the year following diagnosis. The impact of non-adherence to CVD medications on cardiovascular events in BC survivors is unknown.

Methods: Using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked dataset, we evaluated patients with non-metastatic BC who were diagnosed between 2006-2014. Prescriptions were identified for the treatment of hypertension, hyperlipidemia and diabetes. The pre-cancer diagnosis study period for adherence was defined as 1 year prior to the diagnosis of cancer. The follow up adherence period was between years 1 and 2 following the diagnosis of cancer, so the BC treatment period was not included. Adherence was defined as a medication possession ratio of 380%. A CVD event was defined as an ischemic event or acute heart failure. Patients with a CVD event prior to diagnosis were excluded. Logistic regression was performed for each non-cancer condition to define factors associated with medication non-adherence. Cox regression was used to calculate the association between CVD medication adherence and time-to-subsequent cardiac events, adjusted for baseline factors. Cox regression was performed separately for each non-cancer condition.

Results: Among 23,080 women with BC in the cohort, 15,576 were adherent to at least one CVD medication prior to diagnosis, and of these, 2732 (17.5%) were non-adherent to at least one medication following treatment. Among the women adherent to medications prior to diagnosis, 19.2% were non-adherent to hypertension medications, 26.2% were non-adherent to cholesterol medications, and 30.6% were non-adherent to diabetes medications following the first year of BC treatment. Factors that were associated with non-adherence to anti-hypertensives included receipt of chemotherapy (OR 1.24, p<0.001), other comorbidities (OR 1.34, p<0.001), higher stage (OR 1.18, p <0.001) and hormone receptor negative tumors (OR 1.15, p<0.001). Similar factors were associated with non-adherence to cholesterol medications, whereas only stage and tumor type were associated with non-adherence to diabetes medications. Non-adherence to hypertension medications compared to adherence following diagnosis was associated with an increased risk of having a CVD event (HR 1.33, 95% CI 1.18-1.51, p<0.001; 5-year cumulative incidence of 32% vs 26%, respectively, p<0.001). Similar results were seen for adherence to cholesterol medications (HR 1.21, 95% CI 1.05-1.40, p=0.009) and diabetes medications (HR 1.31, 95% CI 1.09-1.56, p=0.003).

Conclusions:In summary, we found that a large proportion of women who were previously adherent to their medications to prevent CVD events prior to their breast cancer diagnosis were non-adherent following treatment. Of concern, non-adherence to any of these classes of medications resulted in an increased risk of having a cardiovascular event. Improving outcomes and reducing morbidity following a breast cancer diagnosis also requires focused attention on non-breast cancer conditions.

Citation Format: Hershman DL, Accordino M, Shen S, Buono D, Crew KD, Kalinsky K, Trivedi MS, Unger JM, Wright JD. Association between adherence to cardiovascular medications and cardiovascular events following a diagnosis of early stage breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD6-10.

Pre-surgical trial of the AKT inhibitor MK-2206 in patients with operable invasive breast cancer: a New York Cancer Consortium trial

INTRODUCTION

The PI3K/AKT/mTOR pathway is an oncogenic driver in breast cancer (BC). In this multi-center, pre-surgical study, we evaluated the tissue effects of the AKT inhibitor MK-2206 in women with stage I-III BC.

MATERIALS AND METHODS

Two doses of weekly oral MK2206 were administered at days - 9 and - 2 before surgery. The primary endpoint was reduction of pAkt^Ser473 in breast tumor tissue from diagnostic biopsy to surgery. Secondary endpoints included changes in PI3K/AKT pathway tumor markers, tumor proliferation (ki-67), insulin growth factor pathway blood markers, pharmacokinetics (PK), genomics, and MK-2206 tolerability. Paired t tests were used to compare biomarker changes in pre- and post-MK-2206, and two-sample t tests to compare with prospectively accrued untreated controls.

RESULTS

Despite dose reductions, the trial was discontinued after 12 patients due to grade III rash, mucositis, and pruritus. While there was a trend to reduction in pAKT after MK-2206 (p = 0.06), there was no significant change compared to controls (n = 5, p = 0.65). After MK-2206, no significant changes in ki-67, pS6, PTEN, or stathmin were observed. There was no significant association between dose level and PK (p = 0.11). Compared to controls, MK-2206 significantly increased serum glucose (p = 0.02), insulin (p < 0.01), C-peptide (p < 0.01), and a trend in IGFBP-3 (p = 0.06).

CONCLUSION

While a trend to pAKT reduction after MK-2206 was observed, there was no significant change compared to controls. However, the accrued population was limited, due to toxicity being greater than expected. Pre-surgical trials can identify in vivo activity in the early drug development, but side effects must be considered in this healthy population.

Concurrent use of capecitabine with radiation therapy and survival in breast cancer (BC) after neoadjuvant chemotherapy

PURPOSE

Capecitabine has been studied as a radiosensitizer, and our study seeks to examine the association of concurrent capecitabine/radiation therapy (RT) on event-free- (EFS) and overall survival (OS) in women with breast cancer (BC) with residual disease after neoadjuvant chemotherapy (NAC).

METHODS/PATIENTS

In a retrospective study of women with BC who received adriamycin/taxane-based NAC from 2004-2016, we identified 21 women administered concurrent capecitabine/RT. To assess differences in survival, we selected a clinical control cohort (n = 57) based on criteria used to select patients for capecitabine/RT. We also created a matched cohort (2:1), matching on tumor subtype, pathological stage and age (< 50 or 50+ years). Differences in EFS, using STEEP criteria, and OS, using all-cause mortality, between those who received capecitabine/RT and controls were assessed.

RESULTS

Of the 21 women who received capecitabine/RT, median age was 52 years. The majority were pathologic stage III (n = 15) and hormone receptor-positive/HER2-negative BC (n = 20). In those receiving capecitabine/RT, there were 9 events, compared with 14 events in clinical and 10 events in matched controls. Capecitabine/RT was associated with worse OS in clinical (HR 3.83 95% CI 1.12-13.11, p = 0.03) and matched controls (HR 3.71 95% CI 1.04-13.18, p = 0.04), after adjusting for clinical size, pathological stage and lymphovascular invasion. Capecitabine/RT was also associated with a trend towards worse EFS in clinical (HR 2.41 95% CI 0.86-6.74, p = 0.09) and matched controls (HR 2.68 95% CI 0.91-7.90, p = 0.07) after adjustment.

CONCLUSION

Concurrent capecitabine/RT after NAC is associated with worse survival and should be carefully considered in BC.

Abstract P6-12-17: Identifying risk factors and effect modifiers of trastuzumab-induced cardiotoxicity among multi-ethnic women with early-stage HER2-positive breast cancer

Introduction: Trastuzumab-based adjuvant therapy is the current standard of care for early-stage HER2-positive breast cancer. However, trastuzumab has also been associated with an increased risk of cardiotoxicity, especially when given following an anthracycline. Trastuzumab-induced cardiotoxicity (TIC) can present as asymptomatic left ventricular ejection fraction (LVEF) decline or symptomatic heart failure. Our objective was to identify predictors of TIC among multi-ethnic patients with early-stage HER2-positive breast cancer. Unlike prior observational studies, our study included a high representation of racial/ethnic minorities, who are at increased risk of cardiovascular disease (CVD) compared to non-Hispanic whites.

Methods: We conducted a retrospective cohort study in patients with stage I-III HER2-positive breast cancer, diagnosed from 2007 to 2015 at Columbia University Medical Center (CUMC) in New York, NY, who had received adjuvant trastuzumab therapy. Participants had at least two serial echocardiograms or MUGA scans to assess TIC, which was defined as at least a 10% decrease in LVEF from baseline or LVEF &lt;50%. LVEF recovery was defined as at least a 10% increase in LVEF or LVEF &gt;50%. We conducted descriptive statistics and univariate and multivariable logistic regression to estimate the associations between socio-demographic factors, breast tumor and treatment characteristics, and CVD risk factors (including smoking status, body mass index [BMI], hypertension, diabetes, hyperlipidemia, coronary artery disease) and TIC. Interactions between race/ethnicity and CVD risk factors were assessed using a logistic regression model.

Results: In our study population (N=279), the mean age was 52.7 years (standard deviation, 12.1) with 36.6% non-Hispanic white, 18.3% non-Hispanic black, 34.8% Hispanic, and 10.4% Asian patients. There were no differences by race/ethnicity in tumor and treatment characteristics (over half had prior anthracyclines), but racial/ethnic minorities had higher BMI and were more likely to have hypertension compared to non-Hispanic whites. About a third of patients developed TIC and 14.7% had an LVEF decline to &lt;50%, of which 15 (16.1%) experienced LVEF recovery. In multivariable analysis, prior anthracycline use and hypertension were significantly associated with increased odds of developing TIC (odds ratio [OR]: 2.25, 95% confidence interval [CI]: 1.25, 4.06; OR: 2.13, 95% CI: 1.15, 3.93, respectively). There was a significant interaction (p=0.027) between race/ethnicity and hypertension on odds of developing TIC with hypertensive non-Hispanic white patients experiencing 6.05 (95% CI: 2.19, 16.75) times the odds of developing TIC compared to non-hypertensive non-Hispanic whites.

Discussion: We observed a higher incidence of TIC and lower incidence of LVEF recovery compared to previous clinical trials. Given patient selection for clinical trials, our results may be more representative of clinical practice settings. We found a particularly high risk among non-Hispanic white patients with hypertension. Patients with hypertension may require closer blood pressure monitoring and treatment with anti-hypertensives in order to reduce risk of developing cardiotoxicity.

Citation Format: Yuan A, Topkara V, Hershman DL, Kalinsky K, Accordino MK, Trivedi MS, Yu A, Genkinger JM, Crew KD. Identifying risk factors and effect modifiers of trastuzumab-induced cardiotoxicity among multi-ethnic women with early-stage HER2-positive breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-12-17.

Abstract PD7-03: Cost-effectiveness analysis of intraoperative radiotherapy for ductal carcinoma in situ

Background

Whole breast radiation therapy (WBRT) following lumpectomy for ductal carcinoma in situ (DCIS) is standard of care, however, the risk of local recurrence with and without radiation ranges as low as 0.9% vs. 6.7% over 7 years. Intraoperative radiotherapy (IORT) is a potential alternative with advantages of decreased toxicity to adjacent organs, convenience, and improved quality of life. While prospective trials of IORT for DCIS are ongoing, the objective of this study was to estimate the cost-effectiveness of IORT vs. WBRT vs. no radiation for DCIS.

Methods

We developed a Markov model using TreeAge Pro 2016 to evaluate the cost-effectiveness of WBRT, IORT, and no radiation in patients with DCIS following lumpectomy. Health states included disease free, local recurrence (ipsilateral DCIS or invasive cancer), distant recurrence or death due to breast cancer, and death due to non-breast cancer causes. A 10-year time horizon and societal perspective were used. Model input parameters were derived from the literature. Costs reflected 2016 Medicare rates. The primary endpoint was incremental cost-effectiveness ratio (ICER), defined as the difference in cost, divided by the difference in quality-adjusted life years (QALYs) of two interventions. We performed analyses of subgroups defined according to DCIS risk (histologic grade, Oncotype Dx® DCIS recurrence score, low risk per RTOG 9804 criteria) and endocrine therapy use (none, tamoxifen, aromatase inhibitor). Sensitivity analyses explored uncertainty in the model.

Results

IORT was the most cost-effective strategy, with an increase of 0.18 QALYs at an incremental cost of $4,728, corresponding to an ICER of $26,943/QALY when compared with no radiation therapy. WBRT resulted in an increase in 0.18 QALYs at an incremental cost of $6859, corresponding to an ICER of $39,085/QALY. For both strategies, the ICERs did not exceed the willingness to pay (WTP) threshold of $100,000.

IORT remained the most cost-effective strategy across DCIS risk groups, but was more cost-effective in higher risk patients, as demonstrated by lower ICERs. In low risk DCIS defined by RTOG 9804 criteria, no radiation was most cost-effective. The ICERs for IORT and WBRT, $152,753 and $208,204/QALY, respectively, exceeded the WTP threshold. IORT remained cost-effective in the setting of endocrine therapy use.

Incremental Cost-Effectiveness Ratios (ICER) for each radiation strategy for the base case and scenario analyses ICER ($/QALY) No RTIORTWBRTBase Case Analysis 26,94339,085    Scenario Analysis by DCIS Risk GroupHistologic Grade   - Low 36,81152,219- High 25,64337,137    Oncotype Dx DCIS Score   - Low 92,892126,398- High 32,00345,690    Low Risk DCIS 152,753208,204    Scenario Analysis by Endocrine TherapyNo Tamoxifen 23,38734,373Tamoxifen 47,81166,616    Tamoxifen 31,96146,272Aromatase Inhibitor 41,31658,674

Conclusion

IORT was the most cost-effective radiation strategy for DCIS compared to WBRT and no radiation. This applied to all subgroups with the exception of low-risk DCIS defined by RTOG 9804 criteria for whom no radiation was the most cost-effective strategy. These findings provide support for ongoing studies examining the role of IORT for DCIS with high-risk features, as well as alternative treatment strategies for low-risk DCIS.

Citation Format: Onishi M, Connolly EP, Wright JD, Vasan S, Gross T, Tsai W-Y, Chen L, Neugut AI, Accordino MK, Kalinsky K, Crew KD, Hershman DL. Cost-effectiveness analysis of intraoperative radiotherapy for ductal carcinoma in situ [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD7-03.

Abstract P5-03-03: Cytotoxic t-lymphocyte density increased within the tumor immune microenvironment of patients with breast cancer following treatment with Akt inhibitor MK-2206

Background: The PAM (PI3K/Akt/mTOR) signaling pathway has been implicated in the oncogenesis of multiple solid malignancies, including breast cancer (BC). Tumor infiltrating lymphocytes (TILs) found within the tumor immune microenvironment (TME) are both prognostic of overall survival as well as predictive of response to neoadjuvant chemotherapy in BC. Our aim is to characterize the TME in a series of patients with operable stage I-III BC treated with MK-2206, an allosteric Akt inhibitor as part of a presurgical, window of opportunity, trial. In our presurgical trial (clinicaltrials.gov #: NCT01319539), patients received 2 doses of MK-2206 with first dose at day -9 and second at day -2 from surgery. Methods: Quantitative multiplex immunofluorescence (qmIF) was performed using immune biomarkers (DAPI, CD3, CD8, CD4, FOXP3, CD68, Pancytokeratin) on full section (4uM) tissue slides from core biopsy specimens and postsurgical specimens of 10 patients - 5 patient treated with MK-2206, and 5 prospectively collected untreated controls. Images were taken using Vectra, a novel pathology workstation and analyzed using inForm software to perform cell classification and phenotyping. Student T- test was used to compare biomarker changes before and after MK-2206. Results: Preliminary analysis demonstrates that patients treated with MK-2206 exhibited a significantly increased median cytotoxic T-cells (CD3CD8+) density, as compared to the matched control cohort (87% vs.0.2%, p &lt; 0.05). We did not identify a change in macrophage (CD68) or T helper/T reg (CD4/CD4FOXP3+) density following MK-2206 treatment in this small cohort. Proximity comparison, using nearest neighbor analysis was used to assess for potential impact of therapy on interactions between CD3CD8+ cells and BC cells. The median distance from CD3+CD8+ cells to nearest neighboring tumor cell was determined in both the pre and post tissues specimens for both groups. In patients treated with MK-2206, a 12.5% reduction in median distance was observed between CD3+CD8+ cells and tumor cells following treatment, suggestive that the increased effector T cells are not relegated to the periphery. This observation was not seen in the pre and post samples of the control cohort. Conclusions: In our study, we found that presurgical Akt inhibition lead to a significant increase in the cytotoxic T-cell population which was in similar proximity, if not closer, to tumor cells as compared to matched controls. Limitations of this exploratory study include a small patient cohort size and use of a single pathology evaluation technique. We are currently expanding our characterization of the TME with a more comprehensive myeloid panel as well as performing additional tissue analysis to validate our findings. At present, there are currently FDA approved therapies, as well as agents in clinical development that exert antineoplastic activity through the PAM pathway. Investigations that endeavor to understand the impact of these therapies on the TME may lead to both an increased understanding of the bioactivity of these agents and potentially identify aspects of the immune response which can be exploited by future immunotherapy therapeutics.

Citation Format: Marks DK, Gartrell RD, Asmar ME, Hart TD, Lu Y, Esancy CL, Hibshoosh H, Connolly EP, Kalinsky KM, Saenger YM. Cytotoxic t-lymphocyte density increased within the tumor immune microenvironment of patients with breast cancer following treatment with Akt inhibitor MK-2206 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-03-03.

Abstract PD3-14: Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer

Background

LIV-1, a transmembrane protein and downstream target of STAT3, is highly expressed in breast cancer cells. It is associated with lymph node involvement and metastatic progression. SGN-LIV1A is an anti-LIV-1 antibody conjugated via a protease-cleavable linker to monomethyl auristatin E (MMAE). Upon binding to cell-surface LIV-1, SGN-LIV1A is internalized and releases MMAE, which disrupts microtubulin and induces apoptosis.

Methods

This ongoing, phase 1 study evaluates safety, tolerability, pharmacokinetics, and antitumor activity of SGN-LIV1A (q3wks IV) in women with LIV-1-positive, unresectable, locally advanced or metastatic breast cancer (LA/MBC) (NCT01969643). Patients (pts) with measurable disease and ≥2 prior cytotoxic regimens for LA/MBC are eligible. Pts with ≥ Grade 2 neuropathy are excluded. Response is assessed per RECIST v1.1; pts with stable disease (SD) or better can continue treatment until disease progression or intolerable toxicity. At completion of dose escalation in hormone receptor-positive/HER2-negative (HR+/HER2–) and triple-negative (TN) pts, expansion cohorts were opened to further evaluate safety and antitumor activity of monotherapy in TN pts. Tumor biopsies are evaluated for LIV-1 expression.

Results

To date, 69 pts (18 HR+/HER2–, 51 TN) have received a median of 3 cycles (range, 1–12) of SGN-LIV1A at doses of 0.5–2.8 mg/kg. Median age was 56 yrs. Pts had a median of 3 prior cytotoxic regimens for LA/MBC; 58 had visceral disease and 37 had bone metastases. No dose-limiting toxicities (DLTs) occurred in 19 DLT-evaluable pts; maximum tolerated dose was not exceeded at 2.8 mg/kg. Expansion cohorts of TN pts were opened at 2.0 and 2.5 mg/kg. Treatment-emergent adverse events (AEs) reported in ≥25% of pts were fatigue (59%), nausea (51%), peripheral neuropathy (44%), alopecia (36%), decreased appetite (33%), constipation (30%), abdominal pain, diarrhea, and neutropenia (25% each). Most AEs were Grade 1/2; AEs ≥ Grade 3 included neutropenia (25%) and anemia (15%). Febrile neutropenia occurred in 2 pts whose total dose exceeded 200 mg per cycle, including 1 treatment-related death due to sepsis. No other treatment-related deaths occurred on-study. Seven pts discontinued treatment due to AEs. In dose escalation, activity was observed in 17 efficacy evaluable (EE) HR+/HER2- pts, with a disease control rate (DCR= CR+PR+SD) of 59% (10 SD), including 1 pt with SD ≥24 wks. Among the 44 EE TN pts (dose escalation plus expansion cohorts), the objective response rate (ORR) was 32% (14 PR) with a confirmed PR rate of 21%, DCR was 64% (14 PR, 14 SD), and clinical benefit rate (CBR=CR+PR+SD ≥24 wks) was 36% (16 pts). For TN pts, median PFS was 11.3 wks (95% CI: 6.1, 17.1); 10 pts remain on treatment.

Of 631 MBC tumor samples of all clinical subtypes evaluated for LIV-1, 91% were positive; 75% had moderate-to-high expression (H-score ≥100).

Conclusions

LIV-1 is expressed in almost all MBC tumors. SGN-LIV1A monotherapy was generally well tolerated and showed encouraging antitumor activity in heavily pretreated TN MBC, with a PR rate of 32%, confirmed PR rate of 21%, and CBR (≥24 wks) of 36%. Response duration data continue to evolve. Enrollment continues in the TN monotherapy expansion cohort.

Citation Format: Modi S, Pusztai L, Forero A, Mita M, Miller KD, Weise A, Krop I, Burris III H, Kalinsky K, Tsai M, Liu MC, Hurvitz SA, Wilks S, Ademuyiwa F, Diab S, Han HS, Kato G, Nanda R, O'Shaughnessy J, Kostic A, Li M, Specht J. Phase 1 study of the antibody-drug conjugate SGN-LIV1A in patients with heavily pretreated triple-negative metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD3-14.

Abstract P1-12-01: Withdrawn

This abstract was withdrawn by the authors.

Abstract P4-22-04: A randomized, double-blind, phase 2 study of ruxolitinib (RUX) or placebo (PBO) in combination with capecitabine (CAPE) in patients (pts) with advanced HER2-negative breast cancer (ABC) and elevated C-reactive protein (CRP), a marker of systemic inflammation

Background: Systemic inflammation is associated with poor prognosis in pts with ABC. The JAK/STAT pathway is a key regulator of inflammatory signaling, associated with tumorigenesis, cell survival, and progression. We evaluated the efficacy and safety of RUX, a JAK1/JAK2 inhibitor, plus CAPE in pts with HER2-negative ABC and high systemic inflammation defined by the modified Glasgow Prognostic Score (mGPS). Methods: In this double-blind phase 2 trial, pts were randomized 1:1 to 21 day cycles of RUX+CAPE or PBO+CAPE: RUX 15 mg or PBO PO BID for 21 d; CAPE 1000 mg/m2 PO BID for 14 d. Key inclusion criteria were systemic inflammation by mGPS of 1 or 2 (ie, CRP &gt;10 mg/L), ECOG performance status ≤2, ≤2 prior chemotherapy regimens, and no prior CAPE. The primary endpoint was overall survival (OS); key secondary endpoints were progression-free survival (PFS), objective response rate (ORR; complete [CR] + partial response [PR]) per RECIST v1.1, clinical benefit rate (CBR; CR + PR + stable disease for ≥6 mo), duration of response, and safety. Treatment differences in OS and PFS were analyzed by the log-rank test; HRs and CIs were analyzed by the Cox proportional hazards model. Results: Baseline characteristics were similar between pts randomized to RUX+CAPE (n=76) vs PBO+CAPE (n=73): mGPS status (1, 82.9% vs 83.6%), hormone receptor (HR) status (positive, 67.1% vs 63.0%), and number of prior chemotherapy regimens for ABC (0, 50.0% vs 50.7%; 1, 38.2% vs 34.2%; 2, 9.2% vs 13.7%). Median treatment durations were 85 d with RUX in the RUX+CAPE group and 65 d with PBO in the PBO+CAPE group. Median OS was 11.2 mo with RUX+CAPE vs 10.9 mo with PBO+CAPE (HR, 0.932; 95% CI, 0.59–1.46; P=0.762). Median OS was 6.1 mo with RUX+CAPE vs 5.5 mo with PBO+CAPE in HR-negative pts and 11.7 mo and 12.2 mo in HR-positive pts. Median PFS was 4.5 mo with RUX+CAPE and 2.5 mo with PBO+CAPE (HR, 0.737; 95% CI, 0.49–1.12; P=0.151). Median PFS was 2.1 mo with RUX+CAPE vs 2.2 mo with PBO+CAPE in HR-negative pts and 6.1 mo and 4.1 mo in HR-positive pts. ORRs were 28.9% and 13.7% (P=0.024) in the RUX+CAPE and PBO+CAPE arms, respectively. The CBRs were 13.2% and 6.8%, respectively (P=0.278). Worsening of hematologic toxicity was higher and rates of grade 3/4 palmar-plantar erythrodysethesia (PPE) were lower (1.4% vs 12.7%, respectively) with RUX+CAPE (Table).

Safety RUX+CAPE (n=71)PBO+CAPE (n=71)%All-GradeGrade 3/4All-GradeGrade 3/4Nonhematologic Adverse Event*Fatigue56.35.643.74.2Nausea54.98.549.35.6Diarrhea47.98.526.82.8PPE46.51.438.012.7Vomiting38.05.629.64.2Hypokalemia15.58.57.02.8Worsening of Hematologic Toxicity†Anemia80.323.956.37.0Lymphopenia40.815.545.112.7Neutropenia39.411.322.52.8Thrombocytopenia39.411.315.51.4*Most common all-grade (≥35%) or grade 3/4 (≥5%) events in the RUX+CAPE arm (safety group). †Laboratory abnormalities.

Conclusion: These data support the prognostic capabilities of the mGPS. The addition of RUX to CAPE for pts with ABC and high systemic inflammation was associated with an improved ORR compared with PBO+CAPE, but did not improve OS or PFS.

Citation Format: O'Shaughnessy J, DeMichele A, Ma C, Richards P, Yardley DA, Wright G, Kalinsky K, Steis R, Diab S, Kennealey G, Geschwindt R, Jiang W, Rugo H. A randomized, double-blind, phase 2 study of ruxolitinib (RUX) or placebo (PBO) in combination with capecitabine (CAPE) in patients (pts) with advanced HER2-negative breast cancer (ABC) and elevated C-reactive protein (CRP), a marker of systemic inflammation [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-04.

Abstract P3-07-06: Inhibition of HDAC6 as targeted therapy for breast cancers

Due to their unique biology, the homeostasis of cancer cells presents different requirements from non-transformed cells. Targeted therapies that interfere with these requirements have been successfully used as highly selective and low toxic anticancer strategies. Recently, we have identified and validated that viability of inflammatory breast cancers (IBC) depends on histone deacetylase 6 (HDAC6) function. Thus, HDAC6 inhibitors, which are currently being tested in advanced clinical trials for other tumor types, represent a novel targeted therapeutic option for these patients.

We reasoned that additional breast cancers, other than IBCs, may present the same dependency and that identification of patient populations that can benefit from HDAC6 targeted therapy would be necessary in order to rapidly transition this finding into the clinic. By using system biology strategies to interrogate the regulatory circuit of breast cancer cells we have found that HDAC6 activity is highly increased in HDAC6-dependent cells, acting as a master regulator. We have also developed an algorithm (HDAC6-score) based on mRNA expression profiling to evaluate the HDAC6 activity of individual tumor samples. Thus, the HDAC6-score works as a biomarker to easily identify cancers with high HDAC6 activity that are likely to depend on HDAC6 function. Using our HDAC6-score algorithm we have analyzed ~3,000 primary breast cancers. Interestingly, we have found that a group of ~20% of breast cancers that is enriched in hormone receptor positive (HR+) and HER2 positive (HER+) tumors presents an HDAC6-score predictive of good response to HDAC6 inhibitors. To validate our findings, we correlate the HDAC6-score and the growth inhibitory response to the leading HDAC6 inhibitor, Ricolinostat, in preclinical breast cancer models in vitro and in vivo. Our preclinical studies confirmed the high levels of HDAC6 activity in HR+ and HER2+ breast cancer cells as well as their sensitivity to HDAC6 inhibition.

Based on our data we have partnered with Acetylon Pharmaceuticals to formally evaluate the anticancer activity of Ricolinostat in breast cancer patients and the predictive value of the HDAC6 score in a clinical trial that has been recently open (the design of this trial will be presented).

Clinical considerations: Despite the success of Pan-histone deacetylase inhibitors (HDACis) against cutaneous T-cell lymphoma, these inhibitors suffer from ineffectively low concentrations in solid tumors and cardiac toxicity due to its activity against HDAC1, HDAC2 and HDAC3, hindering their progress in the clinic. More-selective HDAC inhibitors represent a novel and promising class of anticancer drugs with wider therapeutic indexes. The leading HDAC6 inhibitor Ricolinostat, which is in Phase II trials for multiple myeloma and lymphoma, has a 20-fold more potency for HDAC6 inhibition than other class-I/II histone deacetylases. Thus, Ricolinostat can be dosed more frequently with better tolerability than non-selective FDA-approved HDACis.

Citation Format: Silva J, Kalinsky K, Quayle S, Yang M. Inhibition of HDAC6 as targeted therapy for breast cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-06.

Abstract P4-22-15: Sacituzumab govitecan (IMMU-132), an anti-Trop-2-SN-38 antibody-drug conjugate (ADC) for the treatment of relapsed/refractory, metastatic triple-negative breast cancer (mTNBC): Updated results

Background. mTNBC has an aggressive course with limited effective therapy options and a median progression-free survival (PFS) of 2-4 months (mos) with standard therapy. Sacituzumab govitecan (IMMU-132) is an ADC targeting Trop-2, an antigen present in many epithelial cancers, including TNBC, and delivering SN-38, a topoisomerase I inhibitor as its therapeutic moiety. IMMU-132 was awarded Breakthrough Therapy designation by FDA based on its previously reported activity in relapsed/refractory mTNBC patients. Here we present updated results from the mTNBC cohort of an ongoing phase I/II study (ClinicalTrials.gov, NCT01631552).

Methods. mTNBC patients (pts) received IMMU-132 10 mg/kg on days 1 and 8 every 21 days. Trop-2 expression was not required for enrollment, but available tumor specimens underwent immunohistological (IHC) testing. Efficacy was assessed locally by RECIST 1.1; ORR, PFS and overall survival (OS) were determined for all pts. Pharmacokinetic parameters were estimated in select pts with adequate blood sampling. Immunogenicity to IMMU-132 was examined in all pts.

Results. We previously reported preliminary efficacy results in 51 mTNBC patients. Here we present data on 69 patients with data cutoff June 5, 2016. Median age was 56 years (31-81) and a median of 5 prior therapies (range 1-12), with 66 evaluable for response; ORR was 29% (19/66) 2 confirmed complete (CR) and 17 confirmed partial responses (PR). The median intention-to-treat PFS is 5.6 mos (95% CI, 3.6-7.1 mos) and median OS is 14.3 mos (95% CI, 10.5-18.8 mos). PRs included 2 pts whose tumors did not respond to anti-PD-L1 therapy. The duration of response in the 19 confirmed responders (8 continuing therapy) is 11.5 mos (95% CI = 7.6 to 12.7). The clinical benefit rate (CR+PR+SD&gt;6 mos) for the 66 assessable patients is currently 45.5%. The majority (88%) of archival tumor specimens were moderately (2+) to strongly (3+) positive by IHC for Trop-2, precluding using Trop-2 expression as a selection criterion. Among current adverse events, grade &gt;3 drug-related toxicities included neutropenia (35%), leukopenia (16%), anemia (13%), vomiting (9%), diarrhea (10%), and febrile neutropenia (4%). Clearance kinetics in 8 pts showed IMMU-132 and IgG had a terminal half-life of 15.3 ± 2.7 h and 86.5 ± 40.5 h, respectively, with area under the curve for free SN-38 (unbound) only 3% of the total amount of SN-38 (e.g., IgG bound). Thus, most SN-38 remains bound to the conjugate, and is released at a rate predicted from in vitro serum stability studies. No pt developed anti-IMMU-132 antibodies.

Conclusion The Trop-2-targeting ADC, IMMU-132, delivering cytotoxic doses of SN-38, shows high objective and durable tumor responses with manageable toxicity in heavily-pretreated pts with mTNBC in this updated cohort, supporting further development in this population with an unmet medical need.

Citation Format: Bardia A, Diamond JR, Mayer IA, Isakoff SJ, Abramson V, Starodub AN, O'Shaughnessy J, Kalinsky K, Moroose R, Shah N, Juric D, Shapiro GI, Guarino M, Ocean AJ, Messersmith WA, Berlin JD, Wegener WA, Sharkey RM, Goldenberg DM, Vahdat LT. Sacituzumab govitecan (IMMU-132), an anti-Trop-2-SN-38 antibody-drug conjugate (ADC) for the treatment of relapsed/refractory, metastatic triple-negative breast cancer (mTNBC): Updated results [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-15.

Abstract P4-21-37: Phase I trial of ruxolitinib in combination with trastuzumab in metastatic HER2 positive breast cancer

Background

Preclinical and clinical studies suggest that trastuzumab resistance in HER2 amplified breast cancer (HER2+ BC) is mediated by cross-activation of alternative signaling pathways. Computational analysis and pooled whole-genome RNAi screens in HER2 transformed BC cell lines identified the IL6/JAK2/STAT3 axis as a master regulator pathway. The combination of trastuzumab plus ruxolitinib, a JAK1/JAK2 inhibitor, demonstrated synergistic tumor growth inhibition in mouse xenografts of HER2 transformed BC cell lines. These data provide the rationale for studying the efficacy of ruxolitinib and trastuzumab in a clinical trial.

Design

This is a multi-center, open-label, phase I/II trial of ruxolitinib plus trastuzumab in patients (pts) with HER2+ metastatic BC (MBC) who have progressed on &gt;2 HER2-directed therapies in the metastatic setting (including trastuzumab, pertuzumab and T-DM1). The phase I is an adaptive design with 10 pts, using the time-to-event continual reassessment method to determine the recommended phase II dose. Phase II will be a non-randomized, open-label trial with 30 evaluable pts. The duration of a treatment cycle is 21 days, with trastuzumab given on Day 1 and ruxolitinib taken orally twice daily continuously. The primary endpoint of phase I is to determine the maximum tolerated dose of the drug combination. The phase I dose range for ruxolitinib is 10-25 mg BID (dose level 0: 20 mg BID). Response is assessed by imaging every 9 weeks. Blood samples and optional tissue biopsies are obtained for biomarker analysis at the following time points: pre-treatment, on-treatment C2D1, and at progression.

Results

Phase I started accrual in the fall of 2014. The trial has accrued 12 patients, with 9 evaluable and 3 non-evaluable patients. Of the evaluable patients, the mean age was 55.9 (range 32-69). Of these, 7 were postmenopausal (78%) 5/9 (56%) were estrogen receptor positive, and all had measurable disease. The mean number of prior lines of therapy in the metastatic setting was 5.6 (range: 3-8), including a mean of 3.2 (range: 2-5) prior regimens containing HER2 targeted therapies. As of 6/12/16, 2 patients remain on therapy. As this is an adaptive design, efficacy and drug tolerability will not be mentioned in this abstract to not bias the ongoing analysis. However, we anticipate that by SABCS 2016, 10 evaluable patients will have completed the DLT period – at which point, complete data will be presented.

Conclusion

Ruxolitinib plus trastuzumab is a novel, non-chemotherapy containing regimen. The phase I analysis is ongoing. We plan on reporting full safety/tolerability and efficacy data once 10 evaluable patients have completed the phase I (9/10 have currently completed DLT period). Given an early signal in HER2+ breast cancer, in this heavily pretreated population we will proceed directly to a phase II trial with the combination.

Citation Format: Mundi PS, Lee S, Chi D, Bhardwaj A, Makower D, Cigler T, Crew KD, Hershman DL, Califano A, Silva J, Kalinsky KM. Phase I trial of ruxolitinib in combination with trastuzumab in metastatic HER2 positive breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-21-37.

Abstract OT2-01-19: A randomized phase II trial of fulvestrant with or without ribociclib after progression on aromatase inhibition plus cyclin-dependent kinase 4/6 inhibition in patients with unresectable or metastatic hormone receptor positive, HER2 negative breast cancer

Background

Cyclin dependent kinase 4 and 6 inhibitors (CDK4/6i), including palbociclib and ribociclib (R), have demonstrated remarkable benefit in progression free survival (PFS) in patients (pts) with hormone receptor positive (HR+), HER2- metastatic breast cancer (MBC) when combined with anti-estrogen therapy. Switching between anti-estrogen therapies at disease progression is standard of care in the treatment of HR+ MBC. We evaluate the strategy of switching anti-estrogen therapy to fulvestrant (F) and maintaining CDK4/6 inhibition with R in pts with HR+, HER2- MBC who have progressed on an aromatase inhibitor (AI) + CDK4/6i.

Trial Design

Phase II, multi-center, randomized, double-blind, placebo-controlled trial to evaluate F +/- R in pts with HR+, HER2- MBC who have previously progressed on any AI + CDK4/6i. Pts can be screened and registered at two different time points:

Scenario 1: Before receiving any CDK4/6i

Scenario 2: At the time of progression of disease (POD) while being treated with an AI + CDK4/6i

In scenario 1, the study will provide pts with letrozole + R, but pts will not be randomized until they demonstrate POD. At randomization, pts will be assigned 1:1 to either a) F + R or b) F + placebo, with treatment given in 4-week cycles. F will be given as a 500 mg dose intramuscularly every 2 weeks for 3 times and then every 4 weeks, as per standard of care. R or placebo will be given orally at 600 mg daily, 3 weeks on/1 week off. CT scans and bone scan are to be performed prior to every third cycle. Serum and whole blood samples and optional tissue biopsies for biomarker assessment will be performed prior to study treatment (scenario 1), prior to randomization to R +/- F, and when the patient goes off study.

Main Eligibility Criteria:

1. Age ≥ 18 years with unresectable or metastatic BC

2. Estrogen and/or progesterone receptor positive, HER2 negative, as per ASCO-CAP

3. Postmenopausal status or receiving ovarian suppression

4. Measurable or unmeasurable disease; stable CNS disease allowed

5. No clinically significant cardiac disease

6. No concomitant CYP3A4/5 inducer or inhibitor

Specific Aims

Primary: Progression free survival (PFS), defined as the time from randomization to POD or death.

Secondary: Objective response rate (ORR), clinical benefit rate (CBR = ORR + stable disease rate), overall survival (OS), and duration of response. Pts in scenario 1 will also be assessed for PFS, OS, CBR, and safety while receiving AI + R (pre-randomization).

Biomarker assessment will include amplification of cyclin D1 and cyclin E, phosphoRb and TK1 expression, Rb1 and p16 loss, and ctDNA for ESR1 and PIK3CA mutations.

Target Accrual

132 pts accrued from 11 academic medical centers in the U.S, with a goal of completing accrual in two years (∼60 to 72 pts in each scenario).

Statistical Methods

Assuming a median PFS of 3.8 months with F alone, we predict that F + R will lead to a median PFS of at least 6.5 months. A one-sided log-rank test with a sample size of N=120 and alpha=0.025, achieves 80% power to detect a difference in PFS of 2.7 months. N=132 pts allows for a 10% drop-out rate.

Citation Format: Mundi PS, Codruta C, Accordino MK, Sparano J, Andreopoulou E, Vadhat LT, Tiersten A, Esteva F, O'Regan R, Jain S, Mayer I, Forero A, Crew KD, Hershman DL, Kalinsky KM. A randomized phase II trial of fulvestrant with or without ribociclib after progression on aromatase inhibition plus cyclin-dependent kinase 4/6 inhibition in patients with unresectable or metastatic hormone receptor positive, HER2 negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-01-19.

Abstract P4-01-06: Diffuse optical tomography can predict pathologic complete response in patients with HER2+ or triple negative breast cancer undergoing neoadjuvant chemotherapy

Background

Pathologic complete response (pCR) predicts clinical outcome in women who receive neoadjuvant chemotherapy (NACT) for breast cancer. Identifying who will have a pCR early during NACT has the potential to save patients months of ineffective chemotherapy and limit unnecessary toxicity; however, no method currently is standardly used. Diffuse optical tomography (DOT) uses near-infrared light to measure concentrations of oxyhemoglobin [HbO2], deoxyhemoglobin [Hb], total hemoglobin [HbT], and oxygen saturation [SO2%], and can assess tissue structure and vascularity. As it is inexpensive, fast, and does not require radiation or intravenous contrast no radiation nor IV contrast, DOT has the potential to become an integral part of NACT to predict responses to NACT. Given the particular significance for pCR in HER2+ and triple negative breast cancer (TNBC), we prospectively evaluated whether a 2 week change in DOT parameters could predict pCR after 5 months of NACT in these subtypes.

Methods

We conducted a prospective cohort study of women with stage II-IIIC breast cancer scheduled to receive NACT with 12 weeks of weekly taxol and four cycles of doxorubicin with cyclophosphamide (AC). We evaluated the associations between residual cancer burden (RCB: 0-3; pCR= RCB 0) and changes in DOT measures. Optical imaging was performed at baseline and before the following: Taxol #3, Taxol #5, AC #1, AC #2, and surgery. Correlation and t-testing were used to evaluate the relationship between 2-week DOT changes and pathologic response.

Results

In a prospectively accrued, longitudinal clinical study with DOT, at least 20 patients with HER2+ or TNBC were enrolled. For patients with these tumor subtypes, there was a significant association between pCR after 5 months of NACT (i.e. RCB 0) and change in the following DOT parameters comparing baseline to after 2 weeks of taxol: HBO (p=0.02), HBT (p=0.02), and S02% (p=0.03). No significant association was seen with HB (p=0.20) or water (p=0.85). When looking specifically at patients with TNBC (n=at least 8 patients), these associations were particulars strong between pCR and the following DOT parameters: HBO (p=0.004), HBT (p=0.009), and S02% (p=0.04). Additional patients are anticipated in this study are anticipated to complete NACT and will be reported at SABCS.

Conclusions

Optical imaging can provide imaging biomarkers to monitor breast cancer response to NACT. Early predictions of pathologic response to NACT can be made with high accuracy as early as two weeks after treatment initiation. These findings are specifically strong in TNBC, a group for whom pCR is predictive of clinical outcome.

Citation Format: Kalinsky K, Lee S, Zhong X, Lim EA, Gunther JE, Hibshoosh H, Kim HK, Accordino M, Crew K, Hielscher A, Hershman DL. Diffuse optical tomography can predict pathologic complete response in patients with HER2+ or triple negative breast cancer undergoing neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-01-06.

Abstract P6-11-05: Phase 1 study of CB-839, a small molecule inhibitor of glutaminase (GLS), in combination with paclitaxel (Pac) in patients (its) with triple negative breast cancer (TNBC)

Background: CB-839 is a first-in-class highly selective inhibitor of GLS, a key enzyme in the utilization of glutamine by cancer cells. TNBC has high GLS expression and is very dependent upon GLS-mediated conversion of glutamine to glutamate for tumor cell growth. CB-839 has antitumor activity in vitro and in vivo in preclinical models of TNBC. Recent studies demonstrate that glutamine utilization can contribute to resistance to paclitaxel, a therapy frequently used to treat TNBC patients. Paclitaxel sensitivity is dependent on down-regulation of the glutamine transporter, SLC1A5, and over-expression of SLC1A5 causes paclitaxel resistance. Consistent with these observations, inhibition of glutamine metabolism with CB-839 has demonstrated strong antitumor activity in combination with paclitaxel.

CX-839-001 is an ongoing Phase 1 trial of CB-839 as monotherapy and in combination with approved agents. We previously reported pharmacodynamic studies demonstrating robust inhibition of GLS in pt blood and tumors and excellent tolerability of CB-839 monotherapy in a variety of tumor types including TNBC. In light of the preclinical rationale and monotherapy tolerability a combination arm was opened testing CB-839 with paclitaxel (Pac-CB) in patients with advanced TNBC. We report here updated results on the Pac-CB dose escalation and expansion cohorts.

Methods: Patients with refractory advanced/metastatic TNBC (prior taxane therapy allowed) received escalating doses of CB-839 (400-800 mg BID) in combination with a fixed weekly Pac dose of 80 mg/m2 Days 1, 8, 15 of a 28 day cycle. Upon demonstration of safety and tolerability, an expansion cohort of TNBC pts was opened.

Results: To date, 15 pts have received Pac-CB at three dose levels of CB-839: 7 pts at 400 mg BID, 5 at 600 mg BID and 3 at 800 mg BID with the latter dose level not completed. 40% of enrolled patients have received &gt;5 prior lines of systemic therapy for adv/met disease, and 10 pts have received prior taxane therapy including 5 in the adv/met setting. The Pac-CB combination has been well tolerated with one DLT during dose escalation (G4 neutropenia at 400 mg BID) and a low rate of dose reductions (2 for Pac and 1 for CB-839). Of 15 pts, the best overall response rate (BORR, see Table) has been PR in 20% (3 pts), SD in 47% (7 pts) and PD in 33% (5 pts) with 5 patients remaining on study. At doses ≥600 mg BID (n=8) the BORR is 38% (3 pts), and disease control rate (CR + PR + SD) is 88% (7 pts). All 3 pts with PRs have received prior Pac, including 2 pts with disease that was refractory to Pac in the advanced/metastatic setting.

Conclusions: The Pac-CB combination has been well tolerated and has demonstrated clinical activity in heavily pre-treated pts with TNBC. At doses ≥600 mg BID, BORR has been 38% and DCR 88%. Notably, PRs have occurred in pts with prior Pac therapy, including 2 pts with Pac-refractory disease in the adv/met setting. Updated data on the escalation and expansion cohorts will be presented.

Dose LevelTotal400 mg BID600 mg BID800 mg BIDRECIST Response Evaluable (N)15753PR3 (20%)02 (40%)1 (33%)SD7 (47%)3 (43%)2 (40%)2 (67%)DCR (CR+PR+SD)10 (67%)3 (43%)4 (80%)3 (100%)PD5 (33%)4 (57%)1 (20%)0

Citation Format: DeMichele AM, Harding JJ, Telli ML, Münster P, McKay RR, Iliopoulos O, Whiting S, Orford KW, Bennett MK, Mier JW, Owonikoko TK, Patel MR, Kalinsky K, Carvajal RD, Infante JR, Merit-Bernstam F. Phase 1 study of CB-839, a small molecule inhibitor of glutaminase (GLS), in combination with paclitaxel (Pac) in patients (its) with triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-11-05.

Proteomic modulation in breast tumors after metformin exposure: results from a "window of opportunity" trial

PURPOSE

Reverse Phase Protein Array (RPPA) is a high-throughput antibody-based technique to assess cellular protein activity. The goal of this study was to assess protein marker changes by RPPA in tumor tissue from a pre-surgical metformin trial in women with operable breast cancer (BC).

METHODS

In an open-label trial, metformin 1500-mg PO daily was administered prior to resection in 35 non-diabetic patients with stage 0-III BC, body mass index ≥25 kg/m². For RPPA, formalin-fixed paraffin-embedded (FFPE) samples were probed with 160 antibodies. Paired and two-sample t-tests were performed (p ≤ 0.05). Multiple comparisons were adjusted for by fixing the false discovery rate at 25 %. We evaluated whether pre- and post-metformin changes of select markers by RPPA were identified by immunohistochemistry (IHC) in these samples. We also assessed for these changes by western blot in metformin-treated BC cell lines.

RESULTS

After adjusting for multiple comparisons in the 32 tumors from metformin-treated patients vs. 34 untreated historical controls, 11 proteins were significantly different between cases vs.

CONTROLS

increases in Raptor, C-Raf, Cyclin B1, Cyclin D1, TRFC, and Syk; and reductions in pMAPK^pT202,Y204, JNK^pT183,pT185, Bad^pS112, PKC.alpha^pS657, and Src^pY416. Cyclin D1 change after metformin by IHC was not observed. In cell lines, reductions in JNK^pT183 and Bad^pS112 were seen, with no change in Cyclin D1 or Raptor.

CONCLUSIONS

These results suggest that metformin modulates apoptosis/cell cycle, cell signaling, and invasion/motility. These findings should be assessed in larger metformin trials. If confirmed, associations between these changes and BC clinical outcome should be evaluated. CLINICALTRIALS.

GOV IDENTIFIER

NCT00930579.

Abstract P3-07-52: Identification of serum biomarkers associated with Akt inhibitor MK-2206-induced toxicity in a pre-surgical breast cancer (BC) trial

Background: The PI3K/Akt/mTOR pathway is an important oncogenic driver in BC. A major hurdle in clinical Akt inhibitor development has been dose-limiting toxicities, such as rash. To facilitate the risk assessment of Akt inhibitor associated toxicity, we hypothesize that circulating biomarkers can be identified in proteins secreted by the tumor or tumor microenvironment and systemic response after treatment. Exosomes are small membrane bound vesicles containing proteins, mRNA, miRNA, and lipids that are secreted from host cells and remain viable after long-term storage of blood. In this study, we focused on identifying biomarkers associated with drug rash from serum exosomes in BC patients treated with the Akt inhibitor MK-2206.

Methods: In an open-label pre-surgical trial, 2 doses of weekly MK2206 were administered to patients (pts) with stage I-III invasive BC: first at day -9 and second at day -2 from surgery. Sera were collected before and after MK2206. 200 μL of serum was used to isolate total exosomes by precipitation and centrifugation, followed by trypsin digestion and multiplexing labeling analysis. The Orbitrap mass spectrometer was used to acquire LC-MS/MS data. 1,053 unique proteins were identified from the uniProt database. Maximum false discovery rate level (FDR) for predictive biomarkers was controlled at 26% (q&lt;0.26). Analysis was conducted on pre-MK-2206 and post-MK-2206 treated sera from pts to develop a protein signature associated with rash and identify candidate biomarkers of MK-2206-associated rash.

Results: The study was discontinued after 12 pts were enrolled due to toxicity. Notably, an acneiform/maculopapular rash was observed in 5 pts. Unsupervised principal component analysis on the pre-MK-2206 specimens and the entire set of 1,053 proteins demonstrated that 4 of the 5 pts with rash formed a distinct cluster. 30 proteins were differentially expressed in pre-MK-2206 samples from pts who developed rash vs. no rash (q&lt;0.26), with ≥1.5 fold difference in expression level in those with rash after MK-2206. Ingenuity pathway analysis revealed statistically significant over-representation of pathways involved in lipid metabolism (including MALRD1, AWAT2), nucleic acid synthesis (PPAT, ADSLL1), and protein synthesis (PPIB). 45 proteins were significantly different in post-MK-2206 samples (q&lt;0.285). Lipid metabolism was the most significantly over-represented pathway in post-MK-2206 samples.

Conclusions: We demonstrated that mass spectrometry-based proteomic analysis of patient-derived serum exosomes is a promising approach to study drug-induced toxicity. We found significant changes of circulating proteins before and after MK-2206. Increased expression of different proteins involved in lipid metabolism appears to predict skin toxicity, commonly seen with PI3K/Akt pathway inhibitors. Since the PI3K/Akt signaling pathway plays a role in physiological regulation of lipid metabolism, lipid metabolic profiles of BC patients might be important for predicting the risk and controlling toxicity induced by Akt inhibitors. These toxicity-associated biomarkers should be validated and then assessed prospectively in clinical trials.

Citation Format: Mundi PS, Chen E, Sparano J, Andreopoulou E, Taback B, Wiechmann L, Feldman S, Ananthakrishnan P, Hibshoosh H, Connolly E, Crew K, Maurer M, Hershman DL, Kalinsky K. Identification of serum biomarkers associated with Akt inhibitor MK-2206-induced toxicity in a pre-surgical breast cancer (BC) trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-52.

Abstract PD3-06: Safety and efficacy of anti-Trop-2 antibody drug conjugate, sacituzumab govitecan (IMMU-132), in heavily pretreated patients with TNBC

Background: Triple-negative breast cancer (TNBC) comprises about 15% of all breast cancer types, and has a particularly aggressive course. Following first-line therapy, the median PFS is &lt;3 months, and OS is &lt;10 months. Therefore, new treatment strategies are needed. Since Trop-2 is expressed in &gt;90% of TNBC, as measured by IHC, we conducted a trial to evaluate the safety and efficacy of a humanized anti-Trop-2 monoclonal antibody conjugated to a high concentration of SN-38, a camptothecin that is a topoisomerase I inhibitor and the active metabolite of the prodrug irinotecan, with 2-3 logs higher potency than the prodrug.

Methods: After establishing the optimal repeated dose in a Phase I trial (ClinicalTrials.gov, NCT01631552) involving many different solid cancer types, an expanded Phase II was undertaken in a number of cancers, including TNBC. Patients received 8 or 10 mg/kg IMMU-132 i.v. on days 1 and 8 of 21-day repeated cycles. Assessments of safety and response by RECIST1.1 were made weekly and bimonthly, respectively. Tumor biopsies (archival, at baseline prior to treatment, and at disease progression) were obtained when safe and feasible.

Results: As of May 10, 2015, 58 patients with TNBC, with a median of 4 prior therapies (range, 1-11), were treated with IMMU-132. Grade 3-4 toxicities included neutropenia (26%), febrile neutropenia (2%), diarrhea (2%), anemia (4%), and fatigue (4%). No patient developed antibodies to SN-38 or the antibody, and no patient discontinued therapy due to toxicity. Tumor responses were defined as ORR (CR+PR) in 31% of 49 evaluated patients, including 2 with CR, and a clinical benefit ratio (CR+PR+SD&gt;6 mo) of 49% (63% with SD&gt;4 mo; 23 patients continuing treatment after 1st assessment). The current median progression-free survival is 7.3 months with 44% maturity in 50 patients treated at the 8 or 10 mg/kg dose level. Overall survival data are still not mature 20 months after enrollment of first patient. Clinical efficacy correlated to biomarker studies, including Trop-2 expression (target of antibody), topoisomerase-1 expression (target of SN-38), and homologous recombinant deficiency (HRD) assay (marker of DNA repair), is being studied. Immunohistochemistry results in archival specimens currently show 97% positivity of Trop-2 among 34 specimens evaluated, with 79% having high intensity (2+/3+) staining.

Conclusions: The Trop-2-targeting IMMU-132, delivering cytotoxic doses of the topoisomerase I inhibitor, SN-38, shows manageable toxicity, and encouraging anti-tumor activity in relapsed/refractory patients with TNBC. This ADC appears to have a high therapeutic index in heavily pretreated patients.

Citation Format: Bardia A, Diamond JR, Mayer IA, Starodub AN, Moroose RL, Isakoff SJ, Ocean AJ, Guarino MJ, Berlin JD, Messersmith WA, Thomas SS, O'Shaughnessy JA, Kalinsky K, Maurer M, Chang JC, Forero A, Traina T, Gucalp A, Wilhelm F, Wegener WA, Maliakal P, Sharkey RM, Goldenberg DM, Vahdat LT. Safety and efficacy of anti-Trop-2 antibody drug conjugate, sacituzumab govitecan (IMMU-132), in heavily pretreated patients with TNBC. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD3-06.

Abstract OT3-01-06: Phase I/II trial of ruxolitinib in combination with trastuzumab in metastatic HER2 positive breast cancer

Background:

Integrated analysis of whole genome RNAi screening with computationally reverse engineered interactome models identified IL6/JAK/STAT as a master regulator pathway essential for growth of ErbB2/HER2 positive breast cancer. Ruxolitinib (R), FDA-approved treatment for myelofibrosis, inhibits JAK1 and JAK2. The combination of R plus Trastuzumab (T) is synergistic in tumor growth inhibition in mouse xenografts of HER2 amplified breast cancer cell lines. These data provide a strong rationale for studying the efficacy of combination R and T in a clinical trial.

Trial Design:

A multi-center, open-label, phase I/II (P1/2) trial of R plus T in HER2+ metastatic breast cancer (MBC) who have progressed on T-based therapy. P1 will be an adaptive design with 10 patients, using the time-to-event continual reassessment method. The recommended P2 dose (RP2D) will be used in a non-randomized, open-label P2 trial with 30 evaluable patients (pts). Given the anticipated limited overlapping toxicities, approximately 36 pts (range: 32-40) are expected for the P1/2. The duration of a treatment cycle will be 21 days. R will be taken orally twice a day continuously. The P1 dosing range will be 10-25 mg BID (dose level 0: 20 mg BID). T will be administered on Day 1 of each cycle at standard dosing. Objective Response Rate (ORR) will be assessed by imaging every 9 weeks. Blood samples will be obtained for biomarker analysis, pre-treatment, on-treatment on C2D1, and then at progression. Pre-treatment biopsies from archival tissue or new biopsy, on treatment biopsy on C2D1, and upon progression of disease will be discussed with pts with accessible disease.

Main Eligibility Criteria:

1. HER2 positive MBC

2. Progression on HER2-directed therapy in metastatic setting, including Pertuzumab and T-DM1

3. Measurable or non-measurable disease

4. LVEF great than 50%

5. No history of prior JAK2 inhibitor

6. No HIV-positive or active infection

7. No concurrent medications that are potent CYP3A4 inhibitor or inducer

Specific Aims:

1. Primary: P1: MTD of combined R + T. P2: Progression Free Survival (PFS)

2. Secondary: a) Clinical: ORR, clinical benefit rate (CBR), and tolerability. Pts will be stratified by hormone receptor (HR) status to explore differences in efficacy between HR+ and HR-.

b) Explore potential predictive tumor and blood-based predictive biomarkers at baseline, on treatment, and progression: (tumor: pSTAT3 expression); serum: IL-6, IL-8, C-reactive protein; circulating tumor cell pSTAT3 expression; and tumor gene expression.

Statistical Methods:

Assuming a historical PFS of 8 weeks with single-agent agent HER2-targeted therapy in HER2+ MBC after progressing on T-based therapy, we predict that pts receiving the combination of R plus T will have a PFS of at least 13 weeks. With a 2-sided alpha of 0.05, we have 80% power to detect a difference with 30 pts.

Target Accrual:

Sample Size: 32-40 pts; projected over 2 years at 4 sites: Columbia, Einstein, Mount Sinai, and Cornell. Trial accruing since Fall 2014.

Citation Format: Kalinsky K, Chi D-C, Lee S, Bhardwaj A, Makower D, Cigler T, Crew KD, Hershman DL, Califano A, Silva J, Maurer M. Phase I/II trial of ruxolitinib in combination with trastuzumab in metastatic HER2 positive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-01-06.

Abstract PD3-03: Inhibition of the autocrine IL6-JAK2-STAT3-calprotectin axis as targeted therapy for HR-/HER2+ breast cancers

Although HER2+ tumors are commonly considered as a single entity there is increasing evidence indicating that important intrinsic differences associated to hormone receptor status (HR) exist. Indeed, while HR+/HER2+ patients benefit from anti-hormonal and HER2 targeted therapies, the outcome of HR-/HER2+ patients strongly depends on their response to chemotherapy as well as anti-HER2 therapy. To identify genes that represent novel mechanistic dependencies in HR-/HER2+ breast cancer cells, we designed an integrative approach that combines functional genomic (RNAi screens) and computational algorithms to interrogate regulatory networks reverse engineered.

Our analysis identified STAT3 as a de novo master regulator (MR) gene associated to HER2 mediated transformation in HR- breast cancer cells. Importantly, we demonstrate that aberrant STAT3 activity is necessary to maintain HR-/HER2+ tumor state, thus representing a non-oncogene dependency. Mechanistically we found that HR-/HER2+ breast tumors secrete high levels of IL-6. This acts in an autocrine way to induce the activation of STAT3 via the canonical JAK2/STAT3 pathway. Aberrant STAT3 activity induces upregulation and secretion of the S100A8/9 complex (Calprotectin) triggering a second autocrine stimulus that enhances proliferation and survival via ERK1/2 and AKT. As a result, disruption of the "IL6-JAK2-STAT3-S100A8/9 cascade" compromises HR-/HER2+ cell viability suggesting that the components of this pathway represent putative therapeutic targets in HR-/HER2 tumors.

Importantly, small molecule inhibitors and blocking antibodies for components of this double autocrine loop are already FDA approved or in clinical trials. Here, we demonstrate in vivo that blocking the IL-6 receptor (IL-6R) with the humanized monoclonal antibody Tocilizumab, STAT3 inactivation with the dual JAK1/2 inhibitor Ruxolitinib or Calprotectin inhibition with the small molecule inhibitor Tasquinimod), alone or in combination with anti HER2 therapies, compromises the viability of HR-/HER2+breast cancer cells. Availability of FDA-approved inhibitors to target this novel mechanism represents an exciting opportunity for rapid translation of these findings to the clinics.

Citation Format: Silva J, Rodriguez-Barrueco R, Yu J, Kalinsky K, Maurer M, Califano A. Inhibition of the autocrine IL6-JAK2-STAT3-calprotectin axis as targeted therapy for HR-/HER2+ breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD3-03.

Safety, Feasibility, and Biomarker Effects of High-Dose Vitamin D Supplementation Among Women at High Risk for Breast Cancer

Vitamin D deficiency is a potentially modifiable risk factor that may be targeted for breast cancer prevention. We examined the safety, feasibility, and biomarker effects of high-dose vitamin D among women at high risk for breast cancer. Forty high-risk women, defined as a 5-year breast cancer risk ≥1.67% per the Gail model, lobular or ductal carcinoma in situ, were assigned to a 1-year intervention of vitamin D3 20,000 IU or 30,000 IU weekly. Participants were monitored for toxicity every 3 months, underwent serial blood draws at baseline, 6 and 12 months, and a digital mammogram at baseline and 12 months. Biomarker endpoints included serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D], parathyroid hormone (PTH), insulin-like growth factor (IGF-1), IGF binding protein (IGFBP-3), and mammographic density (MD) using Cumulus software. From November 2007 to January 2011, we enrolled 40 women; 37 were evaluable at 6 months and 30 at 12 months. One patient was taken off study for hypercalciuria; otherwise, the intervention was well tolerated. From baseline to 12 months, mean serum 25(OH)D and 1,25(OH)₂D rose from 20.0 to 46.9 ng/ml and 69.7 to 98.1 pg/ml, respectively (p<0.01). Serum PTH decreased by 12% at 6 months and IGF-1/IGFBP-3 ratio decreased by 4.3% at 12 months (p<0.05). There was no significant change in MD regardless of menopausal status or dose level. We demonstrated that 1 year of high-dose vitamin D3 was associated with a significant increase in circulating vitamin D levels and favorable effects on IGF signaling, but no significant change in MD.

Abstract P3-08-12: Influence of a clinic-based survivorship intervention on dietary change and lifestyle recommendations among Hispanic and non-Hispanic women following adjuvant therapy for breast cancer

BACKGROUND: In 2006, the IOM released a report citing the importance of “survivorship plans” to improve quality-of-life. Little has been done to evaluate their efficacy with regard to uptake of dietary and lifestyle recommendations.

METHODS: Women with early-stage breast cancer were randomized within 6 weeks of completing adjuvant therapy to a survivorship intervention or a control group. Randomization was stratified by ethnicity and subjects were not aware that they were randomized. All subjects were provided the NCI publication, “Facing Forward: Life after Cancer Treatment.” The survivorship intervention group also met with a nurse (1 hour) and nutritionist (1 hour) to receive a treatment summary, surveillance and personalized lifestyle recommendations, based on guidelines from the American Cancer Society and American Institute for Cancer Research. At baseline, 3 and 6 months, both groups completed questionnaires on diet, lifestyle, and perceived health. Linear regression analyses adjusted for ethnicity evaluated the effects of the intervention on comprehension and uptake of lifestyle recommendations. Additional models were run to evaluate the interaction between intervention and ethnicity.

RESULTS: Among 126 women (60 control group, 66 survivorship intervention) mean age was 54 yrs, 48% were Hispanic, and randomized groups were well-balanced by baseline characteristics. Of note, at baseline, compared to non-Hispanics, Hispanics reported lower SES, poorer knowledge of healthy lifestyle behaviors (e.g., diet, physical activity, weight, dietary supplements), lower intake of fruits and vegetables, less recreational physical activity, lower consumption of alcohol, and a lower overall health rating (all P&lt;0.05). After adjusting for ethnicity, at month 3 the intervention group compared to the control group reported greater knowledge of how to eat a healthy diet (P = 0.047), greater knowledge of appropriate use of dietary supplements (P = 0.006), higher levels of physical activity (P = 0.03), and higher intake of fish (P = 0.005). At month 6, the only difference that persisted was greater knowledge of a healthy diet (P = 0.01). In models assessing an interaction between intervention condition and ethnicity, compared to Hispanics, the intervention had a stronger effect on increasing non-Hispanics’ belief that a healthy diet was important to prevent breast cancer recurrence (P = 0.02).

CONCLUSIONS: Compared to only receiving written survivorship materials, a survivorship intervention that included written materials plus a 1 hour personalized lifestyle counseling session was associated with short-term increased knowledge of lifestyle recommendations, change in physical activity and change in dietary behaviors among a multi-ethnic group of breast cancer survivors. Behavioral effects were not observed beyond 3 months. A single 1 hour lifestyle consultation is likely not enough to achieve and maintain lifestyle recommendations. To facilitate long-term behavioral change among breast cancer survivors in the adjuvant setting, culturally competent behavioral interventions should be developed to increase knowledge of and the capabilities needed to meet lifestyle recommendations.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-08-12.

Abstract OT2-6-06: Pre-surgical “window of opportunity” trial of metformin and atorvastatin in newly diagnosed operable breast cancer

Background: Breast cancer requires energy homeostasis shifts with enhanced anabolism to enable rapid growth and continued proliferation. The main energy regulatory system is the AMP-activated kinase (AMPK) pathway triggered by changes in the AMP/ATP ratio. AMPK pathway closely interacts with the PI3K/AKT signaling pathway, with both pathways affecting downstream function of the master regulator mTOR. “Window of opportunity” studies with metformin alone, an AMPK inhibitor, have resulted in mixed results in reducing tumor proliferation in women with early-stage operable breast cancer. Reduction in tumor proliferation has been demonstrated with statins alone (i.e. HMG CoA reductase inhibitors) in pre-surgical trials. Dual therapy with both metformin and atorvastatin demonstrate synergistic activity in preclinical studies in cancer cell lines, showing enhanced anti-proliferative effect. The purpose of this study is to determine the effects of dual therapy with metformin and atorvastatin in women with newly diagnosed BC between breast biopsy and surgery.

Trial Design: Patients (n = 40) will receive metformin 1500mg (500 mg am/1000 mg pm) and atorvastatin 80mg pm, for 2-4 weeks following a diagnostic biopsy and prior to surgery (goal: at least 2 weeks). The main eligibility criteria for this open-label, single-institution, pre-surgical trial include operable stage 0-III BC. Patients must have at least 1 cm of tumor based on palpation or imaging to ensure sufficient pre-treatment tissue. Patients not considered for neoadjuvant chemotherapy are eligible. Specific Aims: Our hypothesis is that pre-surgical metformin plus atorvastatin will result in a significant decrease in the tumor proliferation marker Ki-67. Ki-67 will be log-transformed ln(ki-67), per international guidelines. Secondary objectives include evaluation of functional proteomic changes, such as AMPK/mTOR pathway signaling and apoptosis, by reverse phase protein array (RPPA), as well as assessment of changes in serum insulin, lipids, and markers of the insulin growth factor pathway.

Statistical Methods: Paired t-tests will be calculated to assess modulations in ln(ki-67) before and after treatment. Compared to historical control, we will achieve 80% power with 40 patients, anticipating a -0.523 reduction of ln(ki-67) and standard deviation of 1.15 before and after metformin plus statin (significance level, p = 0.05). We will also be comparing changes in ln(ki-67) in the treated patients to historical controls matched by age, stage, and BMI, using a two-sample t-test at level 0.05. Frequency distributions and summary descriptive statistics will be calculated for all other biomarkers in the two groups. Correlations between all biomarkers and changes in Ki-67 proliferation marker will be analyzed in exploratory fashion. We will also explore differences in modulation of tumor proliferation and functional proteomics in grade III tumors as compared to other tumors. We anticipate accrual 2-3 patient/month, completing the trial within 18 months. Contact information: kk2693@columbia.edu.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT2-6-06.

Abstract OT1-4-03: Phase I study of erlotinib and metformin in triple negative breast cancer

Background: Triple negative breast cancers (TNBC) are enriched for increased phosphorylated EGFR expression and decreased expression of PTEN. We found that combined treatment of metformin and erlotinib induces cell death in a subset of TNBC cell lines with evidence of combined enhanced reduction of EGFR, AKT, S6 and 4EBP1 phosphorylation. Analysis of TNBC cell line alterations led to the hypothesis that loss of PTEN sensitized cells to the drug combination, which was confirmed using isogenic cell line models with and without PTEN expression. The inhibitory effects of combined erlotinib and metformin were confirmed in mouse xenografts of PTEN null TNBC breast cancer cell lines. These data provided a rationale for clinical translation and testing in advanced TNBC patients.

Trial Design: Single institution expanded Phase I design in patients with advanced TNBC. Erlotinib dosing will start and remain at 150 mg. Due to frequent GI upset in patients starting metformin, the dose of metformin will be titrated up to the assigned dose level over 2 weeks. The first metformin dose level will be 850 mg twice daily and will be escalated to its maximum FDA approved dose of 850 mg three times daily. Dose escalation will follow the standard 3 + 3 design. Dose limiting toxicities will be determined during the first 5 weeks of therapy. One metformin dose de-escalation level to 500 mg twice daily is allowed. Cycles will be defined as three weeks of treatment, and response assessments will be performed after every three cycles.

Main Eligibility Criteria:

1. Pathologic diagnosis of TNBC.

2. Measurable or non-measurable disease.

3. At least one prior treatment for metastatic disease.

4. ECOG PS = 0-2.

5. Prior metformin or EGFR targeted therapy.

6. Fasting blood glucose level &lt; 126 mg/dl.

7. Normal renal function.

8. Available archived tumor tissue.

Specific Aims: The primary endpoints are defining the maximum tolerated dose (MTD) of metformin in combination with 150 mg erlotinib, and for the extended phase, determining the potential for clinical benefit by treating 14 patients at the MTD with the goal of rejecting the null hypothesis that the regimen is futile. Clinical benefit is defined as either partial response or lack of progression after 18 weeks of therapy (stable disease). Secondary endpoints include: 1) progression free survival, and 2) pharmacodynamic assessment of the phosphorylation status of AMPK and EGFR from pre- and on-treatment skin biopsies. The exploratory endpoint will be assessment of the status of EGFR, PTEN, LKB1, and 4EBP1 from available patient tumor samples to correlate against treatment response.

Statistical Methods: If one patient meets the primary endpoint, among the 14 patients treated at the MTD, then the regimen will be considered worthy of further investigation.

Target Accrual: 17-20 patients. Four patients accrued as of June 2013. Accrual completion expected June 2015.

Contact: Matthew Maurer, Columbia University Medical Center, mm2058@columbia.edu.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT1-4-03.

Abstract P5-13-01: Uptake of breast cancer chemoprevention among high-risk women and those with ductal carcinoma in situ

Background: Chemoprevention with antiestrogens, such as tamoxifen, raloxifene, and aromatase inhibitors (AIs), reduces breast cancer incidence in high-risk women. However, uptake has been poor in the prevention setting. We examined demographic and clinical factors that influenced chemoprevention uptake in women with an elevated Gail risk score (≥1.67%), lobular/ductal carcinoma in situ (LCIS/DCIS), and/or BRCA mutation carriers.

Methods: We enrolled women prospectively without a diagnosis of invasive breast cancer, who were seen for an initial consultation by breast surgery or medical oncology at Columbia University Medical Center. Eligibility for chemoprevention included a 5-year Gail risk ≥1.67%, LCIS, known BRCA1 or BRCA2 mutation, or hormone receptor (HR)-positive DCIS. Demographic and risk factor data were collected from a self-administered baseline questionnaire and clinical data from medical chart review, including prior/current chemoprevention, type of antiestrogen, duration of use, and toxicities. Differences in distribution of risk factors between women who ever took chemoprevention and those who did not were examined using chi-square statistics or Fisher's exact test. We used log-binomial regression models to estimate relative risks (RRs) and 95% confidence intervals (95% CI) using chemoprevention uptake as the dependent variable. A subset of high-risk women completed questionnaires assessing their attitudes towards chemoprevention and perceived risks/benefits.

Results: Among 412 women enrolled between March 2007 and April 2013, 316 (77%) were eligible for chemoprevention. Main reasons for ineligibility included 5-year Gail risk &lt;1.67% (40%), age &lt;35 (24%), HR-negative DCIS (17%), opting for bilateral mastectomies (11%), and medical contraindications (8%). Among those eligible for chemoprevention, median age 53 (26-88); White/Hispanic/Black/Asian/other (%): 55/29/8/7/1; risk category, 5-year Gail risk ≥1.67%/LCIS/DCIS/BRCA mutation (%): 36/22/40/2. Overall, 162 (51%) women started an antiestrogen (72% for DCIS and 37% among high-risk women), including 114 on tamoxifen, 40 on raloxifene, and 11 on an AI. Early discontinuation occurred in 27 (18%) women, but 7 switched to a different antiestrogen. In univariable analysis, postmenopausal status and medical oncology referral were associated with higher chemoprevention uptake. In multivariable analysis, only higher risk was a significant predictor of chemoprevention uptake. Among the subset of women who completed additional questionnaires on attitudes towards chemoprevention, they reported that the most important factors in chemoprevention decision-making included their healthcare provider (50%), results of chemoprevention studies (44%), and knowledge about others’ experience with chemoprevention (44%). The majority (69%) were concerned about side effects, specifically blood clots with tamoxifen and raloxifene and bone fractures with AIs.

Conclusions: In high-risk women seen at an academic breast center, chemoprevention uptake was relatively high compared to the published literature. Further research is needed to determine how the risks and benefits of chemoprevention are best communicated to women to enhance informed decision-making and increase uptake of chemoprevention strategies.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-01.

Abstract P4-15-03: Proteomic modulation in breast tumors after metformin use: Results from a “window of opportunity” trial

Background: Laboratory and population studies demonstrate that metformin offers a beneficial breast cancer (BC) effect through reduction of serum insulin levels and changes in cellular protein synthesis and growth, such as AMPK pathway signaling. In a pre-surgical metformin trial of overweight/obese, multi-ethnic BC patients, we reported no difference in tumor proliferation, as measured by ki-67. However, reductions in other biomarkers were observed, including reduction in body mass index (BMI), serum cholesterol, serum insulin, and leptin. Reverse Phase Protein Array (RPPA) is a high-throughput antibody-based technique to assess cellular protein activity in signaling networks. The goal of this study was to assess changes in functional proteomics through RPPA in patients treated in a pre-surgical metformin trial.

Methods: Metformin 1500mg PO daily (500mg am/1000 mg pm) was administered for 2-4 weeks prior to resection in 35 patients with stage 0-III operable BC, BMI ≥ 25 kg/m2, and no history of diabetes. Protein was extracted from pre- and post-metformin paraffin-embedded tumor tissue, denatured by sodium dodecyl sulfate, and printed on nitrocellulose-coated slides. Samples were probed with 160 antibodies. Evaluated antibodies associated with various cellular activities, including PI3K/AKT signaling, HSP90 clients, Src/STAT activity, and apoptosis. We analyzed changes in RPPA parameters in tumor tissue of study patients with those of untreated historical controls, matched by age, BMI, and tumor characteristics. Paired t-test was used to calculate within-group changes in RPPA, and two-sample t-tests were used to compare between-group changes in cases and controls (significance: p ≤ 0.05). Multiple comparisons were adjusted for by fixing the false discovery rate (FDR) at 25%.

Results: Of the 35 metformin-treated patients, 32 were evaluable. The majority were Hispanic (80%). Metformin was administered for a median of 23 days (range: 8-64). Of the invasive BCs (n = 21/35), 80% of patients had HR+/HER2- BC. The 33 historical controls were well-matched. For RPPA, the mean total formalin-fixed paraffin embedded protein concentration was 38.9 ug (SD: 3.3). Of the 160 antibodies, 67 antibodies significantly changed after metformin use in the treated group, including reduction in pAKTS473, pAKTT308, and MTOR (unadjusted). Nineteen antibodies were identified as having between group differences in change from baseline: increase in BadpS112, C-RAF, Claudin-7, Cyclin B1, Cyclin D1, EGFR, HER3 pY1298, Lck, PKC-alphapS657, RAD50, Raptor, Syk, and TRFC; reduction in 14-3-3 epsilon, FOXO3a, JNKpT183, MAPKpT202, MEK1pS217, and SrcpY416. Adjusting for multiple comparisons, the following remain statistically significantly different between cases vs. controls: increase in BadpS112, C-RAF, Cyclin D1, and Raptor; and reduction in JNKpT183. Further assessment of RPPA modulation is ongoing, including changes grouped by signaling pathway and activity, as well as validation by immunohistochemistry.

Conclusions: Compared to controls, metformin use associates with changes in apoptosis, cell signaling, C-RAF, and Raptor. These results should be further validated in larger metformin intervention trials to better define populations who may benefit from this therapy.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-15-03.

Abstract P4-01-14: Two-week change in optical tomography predicts residual cancer burden score in women treated with neoadjuvant chemotherapy

Background: A low Residual Cancer Burden (RCB) score after neoadjuvant chemotherapy (NACT) predicts an improved survival in patients (pts) with breast cancer (BC). While an early predictor of tumor response to NACT would allow for treatment optimization, no ideal method exists. Diffuse optical tomography (DOT) is a novel, fast, and low-cost imaging approach that assesses the distribution of water (H2O), oxyhemoglobin (HbO), and deoxyhemoglobin (Hb) concentrations, as a measure of tissue vascularity, without the use of ionizing radiation or breast compression, allowing for safe repeated measurements. We hypothesize that changes in DOT parameters will predict the RCB score following NACT.

Methods: Women with stage II-IIIc invasive BC scheduled to undergo NACT with 12 cycles of a weekly taxane followed by 4 cycles of doxorubicin with cyclophosphamide were enrolled. Treatment with biologic therapies was allowed. DOT assessments were made before starting NACT, 2 weeks into treatment, and before surgery. DOT data were reconstructed into 3D images of the tumor region, from which HbO, Hb, and H2O concentrations were extracted. Final pathology specimens were scored for the RCB index (continuous measure), RCB class (0, 1, 2, 3), and a dichotomized RCB score (RCB class 0 or 1: responders to NACT; RCB class 2 or 3: non-responders). Ki-67 was measured on baseline tumor biopsies and surgical specimens. Correlation analysis, ANOVA testing, and two sample t-tests were used to evaluate the relationship between the 2-week changes in DOT parameters and the RCB score and Ki-67 level.

Results: Since July 2011, we have recruited 24 pts of a total planned accrual of 40. 19 pts have undergone surgery and complete data is available for 13 at this time. Of the 13 pts, 4 had a pCR (RCB 0), 2 had RCB 1, 6 had RCB 2, and 1 had RCB 3. The Pearson correlations between the 2-week change in HbO, Hb, and H2O with the continuous RCB index were 0.76 (p = 0.0022), 0.87 (p = 0.0001), and 0.74 (p = 0.0038), respectively. There was a significant difference in the 2-week Hb change for pts with RCB 0 compared to pts with RCB 1, 2, or 3. There were significant differences in the 2-week change in H2O and HbO for pts with RCB 0 compared to pts with RCB 2. There were also significant differences between DOT parameters by the dichotomized RCB score (table 1). Ki-67 change was correlated with 2-week H2O change (Pearson r = 0.61 p = 0.045).

2-week DOT% change by RCB class and dichotomized RCB score HbOHbOH2ORCB 0-38%-28.5%-6.7%RCB 1-3.9%-2.9%-0.2%RCB 2+2.3%-0.6%+0.7%RCB 3+1.0%+10.9%-0.4%    Responders (RCB 0/1)-26.6%-20%-4.5%Non-Responders (RCB 2/3)+2.1%+1%+0.6%P value0.010.00690.014

Conclusions: Two-week DOT change is an early predictor of response to NACT as measured by the RCB score. We found significant associations between the RCB index and Ki-67 with 2-week changes in HbO, Hb, and H2O. Significantly different changes in DOT parameters were associated with the other RCB classifications. We are analyzing DOT data on the remaining pts and will conduct biomarker assessments of microvessel density changes. Additional pts are being recruited to evaluate DOT's predictive ability by tumor subtype.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-14.