A network approach to developing immuno-oncology combinations in Canada

Immune checkpoint inhibitors have revolutionized care for many cancer indications, with considerable effort now being focused on increasing the rate, depth, and duration of patient response. One strategy is to combine immune strategies (for example, ctla-4 and PD-1/L1-directed agents) to harness additive or synergistic efficacy while minimizing toxicity. Despite encouraging results with such combinations in multiple tumour types, numerous clinical challenges remain, including a lack of biomarkers that reliably predict outcome, the emergence of therapeutic resistance, and optimal management of immune-related toxicities. Furthermore, the selection of ideal combinations from the myriad of immune, systemic, and locoregional therapies has yet to be determined. A longitudinal network-based approach could offer advantages in addressing those critical questions, including long-term follow-up of patients beyond individual trials. The molecular cancer registry Personalize My Treatment, managed by the Networks of Centres of Excellence nonprofit organization Exactis Innovation, is uniquely positioned to accelerate Canadian immuno-oncology (io) research efforts throughout its national network of cancer sites. To gain deeper insight into how a pan-Canadian network could advance research in io combinations, Exactis invited preeminent clinical and scientific advisors from across Canada to a roundtable event in November 2017. The present white paper captures the expert advice provided: leverage longitudinal patient data collection; facilitate network collaboration and assay harmonization; synergize with existing initiatives, networks, and biobanks; and develop an io combination trial based on Canadian discoveries.

Abstract OT3-04-02: Neoadjuvant Her2-targeted therapy +/- immunotherapy with pembrolizumab (neoHIP): An open label randomized phase II trial

Background: In preclinical models HER2-directed therapy administered with checkpoint blockade is synergistic. Clinically, trastuzumab administered with pembrolizumab-mediated checkpoint blockade in trastuzumab-resistant HER2-positive metastatic breast cancer was safe and demonstrated modest activity. However, because checkpoint blockade can confer improved responses when administered earlier in the course of disease, trastuzumab with pembrolizumab administered in the curative-intent, treatment-naive setting may confer life-long, tumor-specific immunity and ultimately, improve cure rates. Moreover, the potential synergy of trastuzumab and pembrolizumab with paclitaxel may overcome the need for dual HER2-blockade. The neo-HIP study is a randomized, multicenter, phase II, open-label trial to evaluate the efficacy and safety of weekly paclitaxel, trastuzumab plus pertuzumab (THP) vs weekly THP plus pembrolizumab (THP-K) vs a HER2 monotherapy regimen (TH-K) as neoadjuvant treatment in patients with HER2-positive early stage invasive breast cancer.

Methods:Patients ≥18 years old with previously untreated, non-metastatic, stage II-III, HER2-positive (by ASCO/CAP guidelines) breast cancer are eligible. Patients with inflammatory breast cancer or bilateral primary tumors are excluded. Adequate organ function and ECOG PS 0-1 are required. Approximately 174 patients will be randomly assigned to 1 of 3 arms with stratification by clinical nodal status (positive vs. negative) and hormone receptor status (positive vs. negative). In arm A, patients will receive T at 80mg/m2 weekly for 12 weeks, H at 8mg/Kg (1 loading dose) and then 6mg/Kg IV every 3 weeks x 3 doses, P at 840mg (1 loading dose) and then 420mg/Kg IV every 3 weeks x 3 doses (THP). In arm B, patients will receive the same regimen as arm A with the addition of pembrolizumab 200mg IV every 3 weeks x 4 doses (THP-K). In arm C, patients will receive the same regimen as arm B, but without pertuzumab (TH-K). Definitive surgery will be 3-6 weeks after the last treatment dose. After surgery, patients in all arms willbe treated per the treating physician's discretion. After completion of post-operative chemotherapy, patients will receive radiotherapy per local clinical standard and those patients whose tumors are hormone-receptor positive will receive hormone therapy as per local standard-of-care. The purpose of this phase II study is to identify whether Arm B (THP-K) and/or Arm C (TH-K) demonstrate a clinically significant improvement in pCR rate when compared with Arm A (THP). The primary end point is pCR rate in the breast and axilla (ypT0/Tis ypN0). Secondary end points include pCR rate by ypT0ypN0 and ypT0/Tis, residual cancer burden index, event free survival, breast conserving surgery rate, safety and overall survival. Exploratory correlative studies will characterize the immunologic responses to the interventions and explore potential predictors of efficacy and toxicity.

Citation Format: McArthur HL, Leal JHS, DiLauro Abaya C, Basho R, Coleman H, Shiao S, Knott S, Tighiouart M, Dadmanesh F, Giuliano A, Verma S. Neoadjuvant Her2-targeted therapy +/- immunotherapy with pembrolizumab (neoHIP): An open label randomized phase II trial [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 OT3-04-02.

Abstract OT2-06-05: A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard peri-operative care in women with residual triple negative early stage/resectable breast cancer after standard-of-care neoadjuvant chemotherapy

Background: Triple negative breast cancer (TNBC) is a biologically distinct subtype with high risk of early relapse, particularly for patients who do not achieve a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC), with an event free survival of < 60% at 3 years. Physical disruption of tumors with cryoablation (cryo) induces inflammation and releases antigens that can activate tumor-specific immune responses. In pre-clinical studies, the combination of cryo with checkpoint inhibition augmented tumor-specific immune responses and prevented cancer recurrence. In clinical studies, the combination of pre-operative ipilimumab (ipi)- +/- nivolumab (nivo)-mediated checkpoint blockade with cryo was safely administered in women with operable, early stage breast cancer and generated intra-tumoral and systemic immune responses (NCT01502592, NCT02833233). In this multi-center, randomized study, we evaluate the disease specific impact of peri-operative ipi, nivo and cryo versus standard care in women with residual TNBC after neoadjuvant taxane-based chemotherapy (NCT03546686).

Methods:Eligible pts are aged ≥18 years, with ER, PR and HER2 negative operable tumors ≥ 1.0 cm after neoadjuvant taxane-based chemotherapy. Approximately 160 patients will be randomized to one of two arms: standard-of-care breast surgery (control arm) or ipi/nivo/cryo followed by standard-of-care breast surgery (intervention arm). Subjects randomized to the intervention arm will undergo percutaneous, ultrasound- (or MRI-) guided cryoablation with concurrent research core biopsy 7-10 days prior to surgery, and will receive a pre-operative infusion with ipilimumab at the dose of 1mg/kg IV, and nivolumab 240mg flat dose IV (1 to 5 days prior to cryoablation). After surgery, patients will receive three additional doses of nivolumab 240mg flat dose IV Q2 weeks. Adjuvant capecitabine is recommended for all participants and will be administered per standard-of-care at the treating physician's discretion. Patients will be stratified by prior platinum administration, prior anthracycline administration, and clinical nodal status (positive versus negative) at enrollment. The primary endpoint is 3-year Event Free Survival (EFS). Secondary end points include Invasive Disease-Free Survival (IDFS), Distant Disease-Free Survival (DDFS), overall survival (OS) and safety. Exploratory correlative studies will be performed on tumor and serum to characterize the immunologic impact of the intervention and to explore predictors of efficacy and toxicity.

Citation Format: McArthur HL, Comen EA, Solomon S, Rodine M, DiLauro Abaya C, Leal JHS, Patil S, Norton L. A randomized phase II study of peri-operative ipilimumab, nivolumab and cryoablation versus standard peri-operative care in women with residual triple negative early stage/resectable breast cancer after standard-of-care neoadjuvant 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 OT2-06-05.

Abstract P2-09-07: Preoperative pembrolizumab (Pembro) with radiation therapy (RT) in patients with operable triple-negative breast cancer (TNBC)

Background: Radiation therapy (RT) induces immune-mediated cell death and could generate a rich supply of tumor antigens if administered in the pre-operative, curative-intent setting. The addition of PD-1 mediated checkpoint blockade to pre-operative RT could thus, generate robust anti-tumor immune responses, induce long-term tumor-specific memory, and ultimately, improve cure rates. This study aims to establish the safety of pre-operative pembrolizumab (pembro)-mediated immune modulation with a RT “boost” equivalent in patients with operable triple negative breast cancer (TNBC) for whom lumpectomy and adjuvant RT are planned (NCT03366844). Serial research biopsies permit interrogation of conventional biomarkers including tumor infiltrating lymphocytes (TILs) and novel immune correlates as potential predictors of response to pembro alone versus pembro with RT.

Methods: Ten women with operable, primary TNBC >2cm for whom breast-conserving therapy is planned are being enrolled in this single-institution pilot study. Study treatment consists of 1 cycle of pre-operative pembro (200 mg IV) alone, followed 3 weeks later by a RT boost (24 Gy/3 fractions) to the primary breast tumor concurrently with pembro (+/- 5 days). Curative-intent, standard-of-care, neoadjuvant chemotherapy (NAC) or breast-conserving surgery is then undertaken within 8 weeks of study enrollment (i.e. within 5 weeks of pembro #2). Adjuvant RT is administered per standard-of-care after surgery, but without a boost dose. Research blood and fresh tumor biopsies are obtained at baseline and after cycles 1 and 2 of pembro. Co-primary endpoints are: 1) safety/tolerability, as defined by the number of patients who do not necessitate a delay in standard-of-care chemotherapy or surgery and 2) change in TIL score. Secondary endpoints include safety/toxicity up to 19 weeks after study enrollment, pCR rates and disease-free survival. Correlative analysis will include single-cell RNA sequencing of the tumor immune infiltrate and multispectral immunohistochemistry

Results: Seven patients enrolled between 12/19/17 and 7/1/18. As of 7/1/18, 5 patients have completed the experimental pembro/RT phase of the trial and are currently completing standard-of-care NAC; 1 patient is currently being treated in the experimental pembro/RT phase; and 1 patient with a cT2N0 tumor at baseline achieved a pathologic complete response (pCR, ypT0/Tis ypN0) after completing the experimental pembro/RT phase followed by anthracycline- and taxane-based NAC. No grade 3 or 4 toxicities have been observed during pembro/RT in the 6 patients completing the experimental phase to date. Three additional patients will be enrolled

Conclusions: This is the first trial of curative-intent, pre-operative checkpoint blockade with RT in breast cancer and the strategy appears to be well tolerated to date. At the time of presentation, safety, change in TIL score, and pCR rates for all patients completing the experimental and NAC phases of the study will be reported.

Citation Format: McArthur HL, Basho R, Shiao SL, Park D, Mita M, Chung A, Arnold B, Martin C, Dang C, Karlan S, Knott S, Giuliano A, Ho A. Preoperative pembrolizumab (Pembro) with radiation therapy (RT) in patients with operable triple-negative breast cancer (TNBC) [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 P2-09-07.

Abstract P2-09-03: Updated efficacy of first or second-line pembrolizumab (pembro) plus capecitabine (cape) in metastatic triple negative breast cancer (mTNBC) and correlations with baseline lymphocyte and naïve CD4+ T-cell count

Background: In mTNBC, anti-PD-1/L1 monotherapy is most effective when administered early in the course of disease, with recent trials demonstrating overall response rates (ORR) of 23-26% in the first-line setting and 5-6% in later lines. This may reflect iatrogenic lymphopenia from preceding cytotoxic chemotherapy. Furthermore, curative-intent chemotherapy is associated with prolonged suppression of naïve CD4+ cells, a T-cell subset that may play a critical role in the generation of de novo anti-tumor immune responses. We present the final clinical results of a pilot study evaluating the safety and efficacy of combining pembrolizumab plus standard-of-care capecitabine in the first/second-line mTNBC setting. We also explore potential associations between clinical benefit and lymphopenia, preceding chemotherapy, and absolute naïve CD4+ counts.

Methods: In a pilot study, we evaluated the tolerability and preliminary efficacy of concurrent pembro (200mg IV q21 day) plus investigator-selected 1st/2nd line paclitaxel (80mg/m2 IV weekly) or oral cape (2,000mg BID, weekly 1 on/1 off). The primary endpoint was tolerability, defined as the proportion of subjects receiving >6 weeks concurrent therapy without dose discontinuation with toxicities reported per CTCAE v4.0. The secondary endpoint was 12-week objective response rate (ORR) by RECIST1.1. Exploratory endpoints included peripheral blood cell enumeration by real-time flow cytometry and routine clinical laboratory. Naïve CD4+ cells were defined as CD45+ CD3+ TCRab+ CD4+ CD45RA+ CCR7+. Here, we report the results of the pilot phase of the cape cohort (NCT02734290).

Results: Twelve of 14 subjects were treated in the first-line setting. All subjects (14/14, 100%) tolerated cape+pembro for >6 weeks, with toxicities consistent with monotherapy cape experience (diarrhea: grade I-II 50%, grade III 7%; hand-foot: grade I-II 71%) that improved with dose-reduction as needed. At 12 weeks, the ORR was 6/14 (42.9%), and the clinical benefit rate (ORR + stable disease) was 8/14 (57.1%). Depressed absolute lymphocyte count at baseline (ALC<1.0/uL: 33% CBR; ALC≥1.0/uL: 75% CBR) and recent exposure to cytotoxic chemotherapy (<6 months: 33% CBR; >6 months: 75% CBR) were associated with reduced clinical benefit. By flow cytometry, subjects experiencing clinical benefit had higher baseline absolute naïve CD4+ counts (average 283 cells/uL v. 93 cells/uL, p=.069).

Conclusions: This study met the primary endpoint of safety for cape plus pembro in mTNBC, with encouraging clinical activity. These data are supportive of further studies evaluating combination chemotherapy plus anti-PD-1/L1 mTNBC. We observed greater clinical benefit in subjects with non-suppressed ALC, less exposure to recent chemo, and higher baseline naïve CD4+ counts, suggesting that iatrogenic immunosuppression can impair response to immune checkpoint therapy in mTNBC. These findings should be confirmed in ongoing randomized trials of immune checkpoint +/- chemotherapy in mTNBC, and should be considered in the design of future clinical trials.

Citation Format: Page DB, Pucilowska J, Bennetts L, Kim I, Sanchez K, Martel M, Conlin A, Moxon N, Mellinger S, Acheson A, Kemmer K, Mitri Z, Vuky J, Ahn J, Abaya C, Manigault T, Basho R, Urba WJ, McArthur HL. Updated efficacy of first or second-line pembrolizumab (pembro) plus capecitabine (cape) in metastatic triple negative breast cancer (mTNBC) and correlations with baseline lymphocyte and naïve CD4+ T-cell count [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 P2-09-03.

Abstract P6-10-05: A pilot study of radiation (RT) and CTLA4-mediated checkpoint blockade with tremelimumab for the treatment of breast cancer brain metastases (BCBM)

This abstract was withdrawn by the authors.

Abstract OT1-01-05: Phase 1b/2 study of intratumoral Ad-RTS-hIL-12 + veledimex in patients with chemotherapy-responsive locally advanced or metastatic breast cancer

Background: Immune-based strategies involving T-cell activation have recently shown significant activity in multiple tumor types. The presence of immune elements in breast cancers has prognostic and predictive impact. Thus, strategies that optimize the interplay between a breast cancer and the effected individual's immune system may be therapeutic. Interleukin-12 (IL-12), a pro-inflammatory cytokine, reverses immune escape mechanisms induced by myeloid derived suppressor and dendritic cells which, in turn, improves the function of activated CD8+ T cells and promotes tumor stroma collapse. Because tumor neoantigens may be generated in response to chemotherapy, IL12-mediated immune modulation may be optimal in patients with chemotherapy-sensitive metastatic breast cancer. Ad-RTS-hIL-12 (Ad) is a novel gene therapy candidate expressing IL-12 under the control of an orally-administered activator ligand, veledimex (V) through the proprietary RheoSwitch Therapeutic System® (RTS).

Trial Design: Open-label, phase 1b/2, single-arm, single-center study of Ad+V in women with stable or responsive disease after ≥ 12-weeks of 1st or 2nd-line chemotherapy. Eligible patients will be placed on chemotherapy-holiday and enter the immunotherapy phase, consisting of a single cycle of Ad administered intratumorally (Day 1), along with V (80 mg QDx7). HER2-directed antibody therapy may be continued during the immunotherapy phase for women with HER2- disease.

Key Eligibility Criteria: Women ≥18 years with histologically-confirmed locally advanced or metastatic breast cancer of any subtype who have achieved a partial response (PR) or stable disease (SD) to 1st or 2nd-line chemotherapy are eligible. Exclusion criteria include use of immunosuppressive drugs, compromised immune function, autoimmune disorder, or brain metastases.

Specific Aims: To evaluate the safety and tolerability of Ad+V immunotherapy in eligible women. Secondary endpoints include 12 week overall response rate, 12 week disease control rate and the impact of treatment on exploratory immune biomarkers.

Statistical Methods: Safety and efficacy will be evaluated separately for HER2-/HER2+ patients. Tumor response will be evaluated by RECIST v1.1 at 6 and 12 weeks. To ensure safety, stopping rules defined by grade 3/4 adverse events and12-week progression rate were adopted.

Target Accrual: Up to 40 patients, including up to 8 patients (20%) with HER2+ disease.

Summary: Ad+V is a novel gene therapy which controls local expression of IL-12 and may induce tumor stroma collapse and stimulation of an anti-cancer T cell immune response. The ability to regulate the production of IL-12 by modulating V dosing may result in an improved therapeutic index in combination with standard of care. The data from this study will directly inform future studies.

Study Contact (Clinical Trials.gov: NCT02423902).

Citation Format: McArthur HL, Page D, Proverbs-Singh T, Solomon S, Hudis C, Norton L, Patil S, Barrett JA, Lebel F. Phase 1b/2 study of intratumoral Ad-RTS-hIL-12 + veledimex in patients with chemotherapy-responsive locally advanced or metastatic 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 OT1-01-05.

Effects of a green tea extract, Polyphenon E, on systemic biomarkers of growth factor signalling in women with hormone receptor-negative breast cancer

BACKGROUND

Observational and experimental data support a potential breast cancer chemopreventive effect of green tea.

METHODS

We conducted an ancillary study using archived blood/urine from a phase IB randomised, placebo-controlled dose escalation trial of an oral green tea extract, Polyphenon E (Poly E), in breast cancer patients. Using an adaptive trial design, women with stage I-III breast cancer who completed adjuvant treatment were randomised to Poly E 400 mg (n = 16), 600 mg (n = 11) and 800 mg (n = 3) twice daily or matching placebo (n = 10) for 6 months. Blood and urine collection occurred at baseline, and at 2, 4 and 6 months. Biological endpoints included growth factor [serum hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF)], lipid (serum cholesterol, triglycerides), oxidative damage and inflammatory biomarkers.

RESULTS

From July 2007-August 2009, 40 women were enrolled and 34 (26 Poly E, eight placebo) were evaluable for biomarker endpoints. At 2 months, the Poly E group (all dose levels combined) compared to placebo had a significant decrease in mean serum HGF levels (-12.7% versus +6.3%, P = 0.04). This trend persisted at 4 and 6 months but was no longer statistically significant. For the Poly E group, serum VEGF decreased by 11.5% at 2 months (P = 0.02) and 13.9% at 4 months (P = 0.05) but did not differ compared to placebo. At 2 months, there was a trend toward a decrease in serum cholesterol with Poly E (P = 0.08). No significant differences were observed for other biomarkers.

CONCLUSIONS

Our findings suggest potential mechanistic actions of tea polyphenols in growth factor signalling, angiogenesis and lipid metabolism.

Abstract P2-16-12: An exploratory analysis of the role of dasatinib in preventing progression of disease in bone in patients with metastatic breast cancer

Introduction: The role of dasatinib, an oral SRC inhibitor is being explored for the treatment of metastatic breast cancer. In a phase I study, we previously established that the combination of dasatinib and weekly paclitaxel was feasible. The activity of this combination is currently being explored in an ongoing phase II trial. Since Src kinase has a major role in osteoclast function and dasatinib has established anabolic and anti-resorptive effects in bone in vitro, we hypothesized that patients receiving this combination would have good control of osseous metastases and primarily develop progression of disease in sites other than bone.

Patients and methods: Patients were included in this analysis if they participated in the phase I or II metastatic breast cancer studies and received dasatinib at or above the recommended phase II dose of 120mg with paclitaxel (80mg/m2 day 1 and 8 of each 21day cycle). Patients who discontinued therapy for reasons other than progression were excluded. Per protocol, patients were required to discontinue bisphosphonates or other bone modulating agents for the first 8 weeks of study due to the potential for hypocalcaemia. Thereafter, they were permitted to receive these agents at the discretion of their treating physician. Patients provided serum samples for correlative studies. Assessment of N-telopeptide of type 1 collagen (NTX), a product of mature bone collagen that reflects bone specific resorption, is planned.

Results: The median age of the 24 patients who met criteria for analysis was 50y (37 - 66y). Of these, 15 (63%) had ER+ disease, and 24 (100%) were negative for human epidermal growth factor receptor (HER2). At study entry, 17 (71%) patients had bone involvement. Following the initial eight week moratorium, 7 (29%) patients received a bisphosphonate or rank ligand inhibitor during treatment with dasatinib + paclitaxel. Patients received a median 2 months (range 1-23) of dasatinib + paclitaxel therapy. To date, 3 (13%) continue on therapy, and 21 (88%) have had progression of disease. Among patients who progressed, 18 (86%) have progressed in visceral sites and only 3 (14%) progressed in bone. Analyses of serum NTX levels are ongoing and will be compared by site of progression.

Conclusion: The potential role of serum NTX as a predictive biomarker of benefit from dasatinib and paclitaxel is being explored and updated results will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-12.

Abstract P6-11-02: Patient characteristics and outcomes for patients with HER2-overexpressing breast cancer with brain metastases undergoing radiation therapy in the pre- and post adjuvant trastuzumab era

Background: Trastuzumab (H) has improved outcomes for patients with HER2 overexpressing (HER2+) breast cancer (BC) and thus increased the at-risk period for development of brain metastases (BM). In this study we describe the characteristics and outcomes of patients with HER2+BCBM who underwent stereotactic radiosurgery (SRS) or whole brain radiation (WBRT) as initial BM treatment (tx) in the pre- and the post adjuvant (adj) H era at MSKCC.

Methods: 100 consecutive pts with HER2+ BCBM who received SRS or WBRT from January 2001 to December 2011 were identified. Clinical, pathologic and tx information were obtained by retrospective review. Pt characteristics at the time of BM diagnosis (dx) and their associations with time from BM to death were evaluated by Kaplan-Meier (KM) curves, log-rank tests, and Cox proportional hazard models.

Results: The median age at BM dx was 54 yrs (range 26-79). 31% and 69% of pts received SRS and WBRT respectively. After the BM dx, 97% continued to receive systemic tx consisting of chemotherapy and/or anti-HER2 tx. 97% of pts received H for MBC and 17% received H in the adj setting (all after 2005). Patient characteristics were compared between pre-adj H (2001-2005) and post-adj H (2006-2011) cohorts. The only significant differences noted between the cohorts in univariate analysis were extra-CNS disease control and use of anti-HER2 therapy after BM dx: pre-adj H era pts had a higher likelihood of extra-CNS disease control (79.5% vs. 52%, p = 0.004) at BM dx and less use of anti-HER2 tx after BM dx (70% vs. 87.5%. p = 0.05). For all pts, the median follow-up for survivors was 33.5 mos (range 18-103). There were 79 deaths. The median survival from BM dx was 19.4 mos (95%CI: 15.5, 26.6). KM curves and log-rank tests showed significantly better survival from BM for pts with higher KPS, single BM, extra-CNS disease control, lack of neurologic sx at BM dx, initial presentation without LMD, use of lapatinib (ever), SRS as initial RT, and use of any anti-HER2 tx after BM dx. Multivariate analysis showed that higher KPS [HR 0.21 (0.09,0.53)], extra-CNS disease control [HR 2.89 (1.67, 5.00)], single BM [HR 4.73 (2.11,10.60)], use of anti-HER2 tx after BM dx [HR 0.30 (0.17,0.53)], asymptomatic status at BM dx [HR 3.69 (1.69,8.07)] were associated with improved survival from BM. Lack of neurologic sx at BM dx was significantly associated with longer survival from BM even after adjustment for other potentially confounding prognostic factors.

Conclusion: These data are mostly consistent with prior reports regarding prognostic factors and inform contemporary clinical trial design. In pts with HER2+BCBM where the majority were subsequently exposed to anti-HER2 and other systemic tx, presence of neurologic sx at BM dx was significantly associated with worse survival after BM dx. Prospective evaluation of screening brain MRI allowing for earlier detection, leading to more careful monitoring or pre-emptive tx of asymptomatic BM may be warranted. The observation of better extra-CNS disease control at BM dx among pts in the pre- adj H era was unexpected, is hypothesis generating, and requires independent confirmation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-02.

Abstract P5-20-07: Phase II Trial of Dasatinib in Combination With Weekly Paclitaxel for Patients with Metastatic Breast Carcinoma

Background: Src kinase plays an important role in proliferation, survival, angiogenesis and metastasis in several malignancies including breast cancer. Therefore, inhibition of Src and other tyrosine kinases (TKs) represents a novel therapeutic approach. Dasatinib is a potent inhibitor of 5 oncogenic TKs, inhibits VEGF-stimulated proliferation, has potent bone anti-resorptive activity and selectively inhibits basal-type breast cancer growth. Preclinically, the combination of dasatinib and paclitaxel had superior antitumor activity to either agent alone. In a previous phase I study, we determined that, in combination with weekly paclitaxel, the optimum dose of dasatinib was 120mg. Of note, 4/9 (44%) patients treated at or above this dasatinib dose level had objective tumor response. We now present results from the phase II trial of this combination.

Methods: Patients with MBC, ECOG PS 0–1, normal hepatic, renal, marrow function were eligible. Patients had measurable, HER2-negative metastatic breast cancer (MBC), ≤2 prior therapies for MBC. Treatment consisted of weekly paclitaxel 80 mg/m2 IV 3/4 weeks + Dasatinib 120mg orally daily. Response was assessed by RECIST after every 8 weeks of therapy. Simon's two-stage optimal design was used to test the null hypothesis of a 15% response rate (RR) against the alternative of a 30% RR. In stage I, planned enrollment was 23 patients based on Type I and Type II errors of 10%. If 4 or more responses are observed, enrollment will be extended to 55 patients. Exploratory correlative biomarkers of clinical benefit include Src phosphorylation (p-Src) in peripheral blood mononuclear cells, plasma levels of VEGFR2 and collagen Type IV, circulating tumor cells (CTCs) and tumor gene expression profiling.

Results: 21 patients (19 females, 2 male) have enrolled; median age 48 (range 30–79). Patients received a median of 1 prior therapy for MBC (range 0–2). 6 patients are not assessable for response: 1 has received <8 weeks treatment, 5 came off study for toxicity (2 hypersensitivity reaction to paclitaxel, 1 infection, 1 diarrhea/nausea, 1 bleeding likely related to anticoagulation). Among the 15 patients assessable for response, best response to date is as follows: 2 (13%) patients partial response, 11 (73%) patients stable disease (SD) and 2 (13%) patients progression of disease. Of patients with SD, 6/11 (55%) continue on treatment after median of 2 months (range 2–10) and 5/11 (45%) patients have come off study after median of 10 months (range 3–21). Most toxicities have been hematological and low grade. Diarrhea and neuropathy have generally been low grade and no new toxicities related to the combination have occurred since expansion into the phase II. Potential biomarkers of clinical benefit including, p-Src, VEGFR2, collagen Type IV, and CTCs will be presented.

Conclusion: Data from this phase II has demonstrated preliminary evidence of activity for weekly paclitaxel and dasatinib 120mg in patients with MBC. These findings are consistent with data from this dose level in the earlier phase I study. Predictive biomarkers of clinical benefit are under investigation.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-20-07.

Standardized uptake value (SUV) by positron emission tomography/computed tomography (PET/CT) as a prognostic variable in metastatic breast cancer (MBC)

3

Background: The accurate prediction of outcome from MBC could be useful if it could guide more effective therapies. Because PET/CT combines anatomical with functional imaging it could enable greater individualization of treatment. However, there is substantial SUV variation by anatomic site. In this retrospective, single-institution study, we examine baseline SUV on PET/CT as a predictor of outcome from MBC.

Methods: Patients (Pts) with ≥1 metastatic lesion on PET/CT performed ≤60 days of diagnosis of MBC from 01/01/2001-12/31/2008 were identified through institutional databases. Pts who rcvd chemotherapy within 30 days prior to PET/CT were excluded. Electronic medical record reports were reviewed and maximum SUV (SUV-MAX) by site for lesions in bone, liver, lung and lymph node (LN) was recorded. In a secondary analysis, PET/CT scans were reviewed and SUV-MAX recalculated. Relationships between SUV-MAX and OS were assessed using Cox regression by site.

Results: We identified 285 pts, median (med) age 57 yrs (range 27-90) who had PET/CT at med of 2.3 yrs (range 0–41) from primary BC (67% ER+ and 21% HER2+). Med time between PET/CT and MBC diagnosis was -9 days (range -58–59). At med follow-up of 53 mths, 163 pts have died. Med OS is 41 mths (95%CI 34-48). The SUV-MAX by site was; bone (N=159) med 7.0 (range 2.1–29.6); liver (N=55) med 8.2 (range 2.9–51.2); lung (N=89) med 4.7 (range 1.1–24.0); LN (N=180) med 6.9 (range 1.2–34.0). On univariate analysis, higher SUV in bone was associated with shorter survival (p<0.001; table). This was maintained in multivariate analyses after adjusting for known prognostic variables (p=0.02). A similar trend for shorter survival for higher SUV was noted in liver (p=0.07). However, no relationship between SUV and OS was noted in lung (p =0.34) and LN (p=0.6).

Conclusions: This large retrospective study of pts with chemotherapy-naïve MBC suggests that SUV-MAX in bone strongly correlates with prognosis.

[Table: see text]

Evaluation of the correlation of baseline blood pressure (BP) and plasma renin activity (PRA) with bevacizumab (B)-mediated hypertension in patients with early-stage breast cancer

602

Background: Although hypertension (HTN) develops in 20–30% of bevacizumab (B)-treated cancer patients, no accurate clinical predictors of B-mediated HTN have been identified. We evaluated baseline blood pressure (BP) and plasma renin activity (PRA) as potential predictors of B-mediated HTN among breast cancer patients enrolled in an adjuvant chemotherapy-B study. Methods: In this phase II study, B was administered concurrently (10 mg/kg IV q2wk x 8) with pegfilgrastim-supported chemotherapy (AC at 60/600 mg/m2 q2wk x4 then nab-paclitaxel at 260 mg/m2 q2wk x4) and continued at 15 mg/kg q3wk thereafter for a total one year of B therapy. The primary endpoint was cardiac safety. A secondary endpoint was the prospective exploration of PRA as a predictor of HTN. Patients with baseline BP >150/100 mmHg were excluded from the study. Peripheral blood for PRA was collected at baseline, week 8, week 16 and every 3 months during B administration. In this preliminary analysis, baseline data was available for 65 of the 80 enrolled patients. Baseline BP and PRA values for those who did and did not develop grade 2–4 HTN were evaluated by Wilcoxon rank sum test. Results: The baseline characteristic medians are: age 45y (27–75), baseline diastolic BP 70 mmHg (52–95), baseline systolic BP 120 mmHg (90–146), and number of B cycles administered 20 (1–21). Twenty-one patients (32%) developed grade 2–4 HTN. Median diastolic and systolic BP among patients with grade 2–4 HTN was 78 and 124 mmHg, respectively, versus 70 and 115.5 mm Hg, respectively, among patients without grade 2–4 HTN (p = 0.0256 and p = 0.0228). There was no significant association between baseline PRA values and the development of grade 2–4 HTN versus not (p = 0.2917). Conclusions: At the time of this preliminary analysis, both baseline diastolic and systolic BP appear to positively predict the development of B-mediated grade 2–4 HTN while baseline PRA does not. Studies exploring the relationship between serial PRAs and the development of HTN for all study participants are ongoing.

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Bone scintigraphy (BS) may no longer be relevant in the era of integrated PET/CT for women undergoing evaluation for suspected metastatic breast cancer (MBC)

Abstract #5007

Background: &#x2028; The accurate detection of osseous metastases frequently has significant prognostic and therapeutic implications at metastatic breast cancer (MBC) diagnosis. However, the ideal paradigm for accurate detection of osseous metastases has not yet been determined. In this retrospective, single-institution study, we compare the diagnostic performance of integrated positron emission tomography/computed tomography (PET/CT) versus bone scintigraphy (BS) for women undergoing extent-of-disease (EOD) evaluation for suspected MBC.&#x2028; Methods:&#x2028; Women undergoing EOD evaluation for suspected MBC with integrated PET/CT and bone scintigraphy (BS) between January 1, 2005 and Dec 31, 2007 were identified through institutional databases. Patients with PET/CT and BS imaging completed within 30-days of each other were included. Women with a prior history of MBC or an active second malignancy were excluded. Electronic medical record (EMR) reports were reviewed and classified as positive, negative or equivocal for detecting osseous metastases. All EMR reports deemed potentially equivocal were reviewed by 2 investigators and consensus reached regarding the final classification. Bone biopsy data, where available, was also recorded.&#x2028; Results:&#x2028; The median age of the 62 eligible women was 54y (33-90y). Overall, PET/CT and BS demonstrated a high degree of concordance. Of the 41 concordant studies, 13 (21%) and 28 (45%) were reported as positive and negative for osseous metastases, respectively. No studies were classified as equivocal by both modalities. Ten positive PET/CT studies were negative by BS, but no PET/CT-negative studies were positive by BS. Of the 10 patients with PET/CT-positive, BS-negative studies, 4 had subsequent bone biopsies, all of which confirmed osseous metastases.&#x2028; &#x2028; Conclusions:&#x2028; This study supports the diagnostic performance of integrated PET/CT in detecting osseous metastases when EOD evaluation for suspected MBC is considered. Whether PET/CT may supplant BS entirely in this setting has not yet been determined.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5007.

Impact of risk-reducing oophorectomy on quality of life in women at risk for ovarian cancer

1520

Background: Factors associated with quality of life (QOL) changes after risk-reducing salpingo-oopherectomy (RRSO) have not been clearly defined. We report the results of a prospective QOL study among women undergoing RRSO at the Memorial Sloan-Kettering Cancer Center. Methods: 101 women undergoing RRSO between April 2000 and April 2004 were included. Participants completed questionnaires evaluating perceived risk, symptoms, cancer-related worries/distress, sexual function and QOL at baseline, and at 6 and 12 months after RRSO. All questionnaires were adapted from validated, standardized instruments. Instrument score changes over time were evaluated by GLM repeated measures analysis. Results: The median age of the participants was 48y; 62.4% were post- menopausal; 47.5% had a deleterious BRCA mutation; 46.5% had a family history of OC; 73.3% had a personal history of breast cancer. 74.1% reported a perceived lifetime OC risk =25%. Mean total symptom and depression scores at baseline did not differ by menopausal status, BRCA mutation status, personal breast cancer history or OC family history. Menopausal subscale scores were significantly lower at baseline among pre-menopausal women. Baseline mean anxiety/distress scores and cancer-specific distress scores were significantly higher among mutation carriers than non-carriers. Among women who completed all 3 questionnaires (n=60), overall QOL measured by SF36 did not change over time. There was a significant interaction of menopausal status at surgery with the changes in total symptom and menopause subscale scores. There was a significant interaction between mutation status and post-operative decline in anxiety/distress scores. At 6 and 12 months, 24 (36.4%) and 22 (42.3%) of women, respectively, reported a worsened sex life and approximately 15% were dissatisfied with their decision to undergo RRSO. Conclusions: Most women perceived themselves at increased risk of OC and were satisfied with their decision to undergo RRSO. Mutation carriers demonstrated significant baseline OC-specific anxiety, but experienced a significant reduction post-RRSO. A significant increase in symptomatology was reported after RRSO, particularly among pre-menopausal women; however, there was no significant overall change in QOL.

No significant financial relationships to disclose.

A population-based study of trastuzumab-mediated cardiotoxicity among early stage breast cancer patients treated with adjuvant trastuzumab

10640

Background: Given the risk of cardiotoxicity demonstrated with trastuzumab (T) in the MBC literature, adjuvant T trials incorporated stringent cardiac monitoring. In 2005, several of these trials were reported with impressive DFS improvements. As a result of these trials, women in the province of British Columbia with HER-2 positive early stage breast cancer were offered T either concurrently or sequentially with their primary chemotherapy regimen. Given the paucity of data surrounding adjuvant T-mediated cardiotoxicity among the general population, we performed a retrospective review of cardiac toxicity among all patients receiving adjuvant T at the BCCA. Methods: Patients receiving adjuvant T between July 1, 2005 and December 31, 2005 either sequentially or concurrently with their primary chemotherapy regimen were identified by screening the BCCA pharmacy database. A chart review was conducted and the T start date; LVEF values at 0, 3 and 6 months; and patients with symptoms suggestive of congestive heart failure were identified. The mean LVEF values at 0, 3 and 6 months were calculated. Results: 133 patients received adjuvant T alone after completing their primary chemotherapy. The mean baseline LVEF was 60.5%. Of the 101 and 11 patients available for analysis at 3 and 6 months, the mean LVEF was 58.5% and 58.4%, respectively. 5 patients (3.8%) developed symptoms of CHF. 58 patients received adjuvant T concurrently with their primary chemotherapy (four cycles of AC followed by four cycles of concurrent paclitaxel and T). Of these, only 18 patients had an LVEF measured at 0 and 3 months, with a mean LVEF of 64.6% and 63.6%, respectively. Of the 7 patients who also had an LVEF measured at 6 months, the mean was 60.5% for an absolute decrease of 4.1% from baseline. One patient (1.7%) had symptomatic CHF. Conclusions: A clinically meaningful rate of cardiotoxicity is seen with both sequential and concurrent adjuvant T. In particular, we have demonstrated a higher rate of cardiotoxicity with adjuvant T alone than was observed in the HERA trial. These findings support ongoing stringent cardiac monitoring among the general population treated with adjuvant T.

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