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.

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 PD9-07: A phase II study of copper-depletion using tetrathiomolybdate (TM) in patients (pts) with high risk breast cancer (BC): Role of collagen processing and tumor microenvironment

Background: Copper is an important catalytic cofactor in several biological functions and is essential for lysyl oxidase (LOX), a key enzyme in cross-linking collagen, which may play a role in tumor metastasis. We hypothesized that tetrathiomolybdate (TM)-associated copper depletion (CD) would inhibit tumor metastases by altering copper dependent collagen remodeling in the pre-metastatic niche. These results are an update of our previously reported clinical outcomes with longer follow-up and translational outcomes implicating the tumor microenvironment in metastatic transformation of BC. Methods: Pts at high risk for recurrence, node+ triple negative (TNBC) or stage 3/4 BC with no evidence of disease (NED), were enrolled on a phase II study of CD with TM. TM was given to maintain ceruloplasmin (Cp) levels between 8-16 mg/dl for two years (yrs) with an extension phase or until relapse. Median Cp levels were monitored with each cycle. Clinical endpoints included safety/tolerability and progression of disease (POD)/death. Event-free (EFS) and overall survival (OS) were calculated using Kaplan Meier survival analyses. Translational endpoints included markers of collagen cross-linking (LOXL-2), formation (PRO-C3), and degradation (C1M and C6M). Results: Seventy-five pts received 2993 cycles of TM on the primary (24 cycles, 28 days per cycle) and extension study. Median age was 51 yrs (range 29-66). Forty-five pts had stage 2/3 BC, and 30 pts were stage 4 NED. At a median follow-up of 8.4 yrs, the overall EFS was 71.4% and OS was 78.8%. The EFS and OS for the 36 pts with TNBC were 71.7% and 81%, and the EFS and OS for the 39 pts with Luminal/HER2+ BC were 71.2% and 78.6% respectively. TM was well tolerated with grade 3/4 toxicities including: neutropenia (1.9%), febrile neutropenia (0.03%), and fatigue (0.2%). LOXL2 levels were significantly decreased at 12 and 24 cycles compared with baseline (p<0.01) in those who were NED but not in those who had progressive disease (POD). LOXL2 levels were significantly correlated with C1M levels (spearman coefficient -0.34, p=0.02). C1M levels were significantly increased at 5, 11 and 24 cycles as compared with baseline (p<0.01) in those who were NED and were significantly higher as compared to levels in those experiencing POD/death, p<0.05. This difference may be more pronounced in those not achieving adequate CD (<50%) and in luminal/HER2+ BC. Interestingly, the ratio of C1M/PRO-C3 was significantly more elevated over time in those NED as compared to those experiencing POD/death. No associations were found with other collagen markers (PRO-C3 and C6M). Conclusions: TM is safe, well-tolerated and associated with decreased LOXL-2 and increased C1M levels over time in NED pts. This suggests that copper depletion may result in decreased collagen crosslinking and increased collagen degradation over formation, potentially “normalizing” the collagen microenvironment to create an inhospitable environment for tumor metastases. Larger randomized trials in high risk populations with translational outcomes are needed to further investigate the role of collagen processing in the tumor microenvironment and its potential as a biomarker of response.

Citation Format: Liu YL, Bager CL, Willumsen N, Kornhauser N, Cobham M, Andreopoulou E, Cigler T, Moore A, LaPolla D, Fitzpatrick V, Ward M, Warren JD, Mittal V, Vahdat LT. A phase II study of copper-depletion using tetrathiomolybdate (TM) in patients (pts) with high risk breast cancer (BC): Role of collagen processing and tumor microenvironment [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 PD9-07.

Abstract P1-10-10: Tumor infiltrating lymphocytes (TILS) among high risk for recurrence breast cancer patients treated with tetrathimolybdate (TM)

Background: Tumor infiltrating lymphocytes (TILs) evaluated in the primary tumor biopsy or surgical resection have been well established as having prognostic significance in patients with triple negative breast cancer (TNBC) and HER2+ breast cancer treated with adjuvant chemotherapy (Savas et. al, Nat Rev Clin Oncol 2016). In TNBC, stromal TILs behave as a continuous variable with every 10% increase in TIL resulting in a decrease in risk of recurrence and death. The definition of lymphocyte-predominant breast cancer (LPBC) has been used for tumors that contain 50%–60% TILs and usually have a particularly good outcome (Salgado et al, Ann Oncol 2015). Our group recently demonstrated in a phase II single arm study that tetrathimolybdate (TM), a copper-depleting agent, resulted in improved event free survival (EFS) for TNBC patients compared to historical controls. The 2-year event-free survival (EFS) for stage 2-3 and stage 4 NED was 91% and 67%, respectively. In this analysis, our goal was to explore whether the encouraging results we observed were influenced by enrolling TNBC patients with better prognostic factors at initial diagnosis, namely higher stromal TIL score, in our copper depletion trial.

Methods: Archived primary breast tissue was available from 67 of the 75 patients enrolled in the phase II TM trial. The phase II study included patients with stage II TNBC or stage III or IV NED breast cancer patients, who were treated with TM for 2 years or until relapse. Here we focused on the 30 patients with TNBC. The demographic data for the patients is included in the following table.

Patient DemographicsAge at diagnosisStage at study entryPrior Adjuvant or Neoadjuvant therapyNumber of prior chemotherapy regimens in metastatic setting%Tumor Infiltrating Lymphocytes504Adjuvant110543AAdjuvantn/a30563AAdjuvantn/a20513CNeoadjuvantn/a<5454Adjuvant230514Neoadjuvant210363CAdjuvantn/a20592BAdjuvantn/a60453CAdjuvantn/a<5544Adjuvant130443CNeoadjuvantn/a20474Adjuvant020563CNeoadjuvantn/a10512AAdjuvantn/a10583AAdjuvantn/a20654None25513CNeoadjuvantn/a50503CNeoadjuvantn/a30543CNeoadjuvantn/a10542AAdjuvantn/a20403CNeoadjuvantn/a40604Adjuvant160564None160554Adjuvant010633CNeoadjuvantn/a5424Adjuvant050454Adjuvant110463AAduvantn/a10523CNeoadjuvantn/a10514Adjuvant1<5

The number of TILs in each sample was calculated by an experienced pathologist using published criteria (Salgado et al, Ann Oncol 2015). We used TILs >50% to define LPBC.

Results: Overall, we found that only 3/30 (10%) of TNBC patients had TILs >50%. In addition, 14/30 (46.7%) of TNBC patients had tumors with <10% TILs. The 2-year EFS for the patients with TILs >10% v. <10% was 76.9% v. 69.8%, respectively. (P=0.65)

Conclusions: Only 10% of TNBC patients enrolled in the study had LPBC at diagnosis thus indicating that this cohort was not enriched for patients with immunogenic tumors. When stratified by TILs >10% or <10%, there was no statistically significant difference in EFS. Although the analysis is limited due to the small sample size, it does suggest that the amount of TILs present at initial diagnosis did not influence the overall outcome for patients treated with TM.

Citation Format: Rybstein MD, Nackos E, Kornhauser N, Cigler T, Andreopoulou E, Moore A, Cobham M, Fitzpatrick V, Demaria S, Vahdat LT. Tumor infiltrating lymphocytes (TILS) among high risk for recurrence breast cancer patients treated with tetrathimolybdate (TM) [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 P1-10-10.

Abstract P1-10-02: A phase II study of copper-depletion using tetrathiomolybdate in patients with breast cancer at high risk for recurrence: Updated results

Background: Metals have emerged as a viable therapeutic target for a new generation of anti-cancer and anti-metastatic agents. Copper, an essential trace element, serves as an important catalytic cofactor in several biological functions and has emerged as an essential factor in carcinogenesis. Among other elements, bone marrow derived VEGFR2+ endothelial progenitor cells (EPCs) and copper-dependent lysyl oxidase (LOX) are key elements in tumor progression. We hypothesized tetrathiomolybdate (TM)-associated copper depletion (CD) inhibits tumor metastases by reducing the number of EPCs and other copper dependent processes in the pre-metastatic niche. These results are an update of our previously reported study (Chan N, Willis A, Kornhauser N et al. Influencing the Tumor Microenvironment: Phase 2 Study of Copper Depletion with Tetrathiomolybdate in High Risk Breast Cancer and Preclinical Models of Lung Metastases. Clin Cancer Res. October 21, 2016) with longer follow-up.

Methods: A single arm phase II study of breast cancer (BC) patients (pts) at high risk for recurrence, defined as node+ triple negative (TNBC), stage 3 and 4 with no evidence of disease (NED) were enrolled on a trial of CD with TM. TM was given to maintain ceruloplasmin (Cp) levels between 8-16 mg/dl for two years with an extension phase or until relapse. The primary endpoint was a change in EPCs measured by flow cytometry before and during treatment. Secondary endpoints included tolerability, safety, PFS and LOXL-2 levels.

Results: Seventy-five pts received 2778 cycles of TM on the primary and extension study. The primary study treatment duration was 24 cycles (each cycle is 28 days) plus an extension phase. The median age is 51 years (range 29-66). Forty-five pts have stage 2/3 BC and 30 with stage 4 NED. Forty-eight percent of pts are TNBC and 40% of pts are stage 4 NED. Median Cp levels were monitored with each cycle. A decrease from 28 to 16 (p<0.0001) was seen after one cycle. Interestingly, TNBC pts seemed to have a greater decrease from 23.5 to 13 after one cycle. TM was well tolerated with grade 3/4 toxicities including: reversible neutropenia (2.3%), febrile neutropenia (0.04%), fatigue (0.2%). Five-year analysis showed a decrease in EPC's (p=0.004) and LOXL-2 (p<0.001). At a median follow-up of 7.1 years, the EFS for 75 pts is 71.4%. The EFS for 36 pts with TNBC is 71.7%. EFS for stage 2/3 TNBC is 83% and for stage IV TNBC is 59.3%.

Conclusions: TM is safe, well tolerated and appears to affect multiple components of the tumor microenvironment that have been identified in pre-clinical models as important for progression. Ongoing studies in banked specimens are underway to further delineate its effect on copper dependent processes necessary for metastases. Randomized trials are warranted, especially in patients who are at high risk for relapse such as those with TNBC.

Citation Format: Sahota S, Willis A, Kornhauser N, Ward M, Cobham M, Cigler T, Moore A, Andreopoulou E, Fitzpatrick V, Schneider S, Prima N, Wiener A, Ko D, De Laurentiis A, Warren JD, Rubinchik A, Mittal V, Vahdat LT. A phase II study of copper-depletion using tetrathiomolybdate in patients with breast cancer at high risk for recurrence: Updated results [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 P1-10-02.

Abstract P1-12-01: Withdrawn

This abstract was withdrawn by the authors.

Hybrid capture-based genomic profiling of circulating tumor DNA from patients with estrogen receptor-positive metastatic breast cancer

BACKGROUND

Genomic changes that occur in breast cancer during the course of disease have been informed by sequencing of primary and metastatic tumor tissue. For patients with relapsed and metastatic disease, evolution of the breast cancer genome highlights the importance of using a recent sample for genomic profiling to guide clinical decision-making. Obtaining a metastatic tissue biopsy can be challenging, and analysis of circulating tumor DNA (ctDNA) from blood may provide a minimally invasive alternative.

PATIENTS AND METHODS

Hybrid capture-based genomic profiling was carried out on ctDNA from 254 female patients with estrogen receptor-positive breast cancer. Peripheral blood samples were submitted by clinicians in the course of routine clinical care between May 2016 and March 2017. Sequencing of 62 genes was carried out to a median unique coverage depth of 7503×. Genomic alterations (GAs) in ctDNA were evaluated and compared with matched tissue samples and genomic datasets of tissue from breast cancer.

RESULTS

At least 1 GA was reported in 78% of samples. Frequently altered genes were TP53 (38%), ESR1 (31%) and PIK3CA (31%). Temporally matched ctDNA and tissue samples were available for 14 patients; 89% of mutations detected in tissue were also detected in ctDNA. Diverse ESR1 GAs including mutation, rearrangement and amplification, were observed. Multiple concurrent ESR1 GAs were observed in 40% of ESR1-altered cases, suggesting polyclonal origin; ESR1 compound mutations were also observed in two cases. ESR1-altered cases harbored co-occurring GAs in PIK3CA (35%), FGFR1 (16%), ERBB2 (8%), BRCA1/2 (5%), and AKT1 (4%).

CONCLUSIONS

GAs relevant to relapsed/metastatic breast cancer management were identified, including diverse ESR1 GAs. Genomic profiling of ctDNA demonstrated sensitive detection of mutations found in tissue. Detection of amplifications was associated with ctDNA fraction. Genomic profiling of ctDNA may provide a complementary and possibly alternative approach to tissue-based genomic testing for patients with estrogen receptor-positive metastatic breast cancer.

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>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 >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 P6-11-03: A phase 2 open-label study of lucitanib in patients (pts) with FGF aberrant metastatic breast cancer (MBC)

BACKGROUND: Lucitanib is a potent, oral antiangiogenic tyrosine kinase inhibitor of Vascular Endothelial Growth Factor Receptors 1-3 (VEGFR1-3), Platelet-Derived Growth Factor Receptors alpha and beta (PDGFRα/β), and Fibroblast Growth Factor Receptors 1-3 (FGFR1-3). FGF aberrancies (amplification of FGFR1,or 11q[amplicon containing FGF ligands 3, 4, and 19]), are genomic alterations observed in over 20% of breast cancer pts and promote cancer proliferation and survival.

METHODS: MBC pts who had received at least 1 metastatic line of therapy were randomized 1:1 to 10 or 15 mg QD of lucitanib. Stratification was based on local assessment of FGF aberrancy; pts with both FGFR1 and 11q-amplified tumors were stratified as FGFR1 amplified. Central confirmation of FGFR1 or 11q amplification was done using Abbott FISH probes (FGFR1 or 11q copy number ≥ 6 and a ratio of FGFR1 or 11q to centromere ≥ 2). Investigator-assessed progression-free survival (PFS) was the primary endpoint. Secondary endpoints included objective response rate (ORR) per RECIST 1.1, disease control rate (DCR), duration of response (DR), and incidence of treatment-emergent adverse events (TEAE).

RESULTS: Enrollment completed in 3/2016; 178 pts that received at least 1 dose of lucitanib are included in this analysis (baseline characteristics in Table 1). Due to grade 3 hypertension in the 15 mg group (46% vs 37% in 10 mg group), enrollment to the 15 mg group was halted. Overall, most pts (97%) experienced at least 1 TEAE, with the most frequently (≥ 30%) occurring events being hypertension (73%), fatigue (48%), nausea (43%), hypothyroidism (40%), and headache (33%). Grade ≥ 3 TEAEs occurred in 66% of pts, with hypertension as the most frequent event (40%) followed by proteinuria and hyponatremia (both 6%). AEs were manageable with dose interruption or reduction, with approximately 8% of pts ending treatment due to an AE. Current median PFS is 3.5 mos (95% CI 2.8-4.6; range 0.62-12.95) and 2.6 mos (95% CI 1.8-2.9; range 0.82-18.87) respectively for the 10 mg and 15 mg treatment groups. No differences in clinical activity were observed by treatment group, FGF aberrancy, hormone receptor or HER2 status. Of the 168 evaluable pts, confirmed ORR was 3%; overall DCR was 27% (32% for pts in the 10 mg group compared to 20% for the 15 mg group); overall mean (standard deviation) DR of 3.3 (1.8) mos.

Baseline Characteristics 10 mg QD15 mg QD N=109N=69Age (years)Median5653Range27-8227-80SexFemale109 (100%)67 (97%)Male02 (3%)ECOG PSmissing5 (5%)2 (3%)051 (47%)30 (43%)153 (49%)37 (54%)Number of prior anticancer therapies in the metastatic setting> 332 (29%)21 (30%)3-648 (44%)32 (46%)> 629 (27%)16 (23%)Endocrine/HER2 statusmissing7 (6%)1 (1%)ER+ or PR+74 (68%)50 (73%)HER2+12 (11%)7 (10%)TNBC16 (15%)11 (16%)FGFR aberrancyFGFR1 amplified54 (49%)29 (42%)11q amplified31 (28%)24 (35%)FGFR1 and 11q amplified13 (12%)9 (13%)FGFR1 and 11q non-amplified11 (10%)7 (10%)

CONCLUSION: At 10 mg QD, lucitanib has modest activity with manageable toxicity in this heavily pretreated pt population. Future clinical development for lucitanib may focus on alternative biomarkers to identify sensitive tumors and rational combinations with other anti-cancer drugs.

Citation Format: Mayer IA, Arteaga CL, Nanda R, Miller KD, Jhaveri K, Brufsky AM, Rugo H, Yardley DA, Vahdat LT, Sadeghi S, Audeh MW, Rolfe L, Litten J, Knox A, Raponi M, Tankersley C, Isaacson J, Wride K, Morganstern DE, Vogel C, Connolly RM, Gradishar WJ, Patel R, Pusztai L, Abu-Khalaf M. A phase 2 open-label study of lucitanib in patients (pts) with FGF aberrant metastatic breast cancer (MBC) [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 P6-11-03.

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 <3 months, and OS is <10 months. Therefore, new treatment strategies are needed. Since Trop-2 is expressed in >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>6 mo) of 49% (63% with SD>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 OT1-03-15: The METRIC trial: A randomized international study of the antibody-drug conjugate glembatumumab vedotin (GV or CDX-011) in patients with metastatic gpNMB-overexpressing triple-negative breast cancer (TNBC)

Background

Glycoprotein NMB (gpNMB) is an internalizable transmembrane protein overexpressed in approximately 20% of breast cancer (BC), including approximately 40% of TNBC. gpNMB is a poor prognostic marker in BC (Rose CCR 2010) and preclinically has been implicated in tumor invasion, metastasis, and angiogenesis. GV is a novel antibody-drug conjugate targeting the potent cytotoxin monomethylauristatin E (MMAE) to gpNMB overexpressing cancer cells.

In a Phase I/II study and the Phase II "EMERGE" study, GV demonstrated promising activity with TNBC patients (pts) deriving the greatest benefit and exhibiting the highest degree of gpNMB overexpression. GV was well-tolerated with the most frequent treatment-related toxicities consisting of rash, neutropenia, and neuropathy. In subset analyses of the EMERGE trial, objective response rate (ORR) was 30% (7/23) for GV vs. 9% (1/11) for investigator's choice in tumors with gpNMB overexpression (>25% of tumor epithelium); 18% (5/28) vs. 0% (0/11) in TNBC; and 40% (4/10) vs. 0% (0/6) in gpNMB-overexpressing TNBC for GV and IC respectively, with apparent improvements in progression-free survival (PFS; hazard ratio (HR) = 0.11) and overall survival (OS; HR = 0.14).

Trial design

The METRIC Trial (NCT#01997333) is an international (USA, CA, Aus), two-arm phase II study. Pts are randomized 2:1 to GV (1.88 mg/kg IV q 21 days) or capecitabine, a current standard of care for this population (2,500 mg/m2 daily for d1-14, q21 days) until progression or intolerance. Crossover is not permitted.

Eligibility criteria

Key eligibility criteria include: >25% of tumor epithelium gpNMB+ by central immunohistochemistry (IHC) screening of archival tissue; estrogen receptor and progesterone receptor <10% and HER2 negative [0-1+ IHC, or ISH copy number <4.0/ratio <2.0] by local assessment; ECOG 0-1; taxane resistance; anthracycline exposure (if indicated); <2 chemotherapy regimens for advanced BC; measurable disease; no persistent Grade >2 toxicity.

Specific aims

The primary endpoint is PFS per independent, blinded central review committee according to RECIST 1.1. Secondary endpoints are ORR, duration of response, OS, safety, pharmacokinetics and pharmacodynamics. Exploratory endpoints are quality of life and/or cancer-related pain.

Statistical methods and target accrual

The trial has 85% power to detect a PFS HR of 0.64 with two sided α = 0.05. The hypothesized median PFS is 4.0 months for capecitabine and 6.25 months for GV. Target accrual is open for 300 pts.

Citation Format: Melisko M, Yardley DA, Blackwell K, Forero A, Ma C, Montero A, Daniel BR, Wright G, Fehrenbacher L, Chew H, Ferrario C, Nanda R, Seiler Jr M, Guthrie T, Vance K, Ouellette G, He Y, Bagley RG, Zhang J, Vahdat LT. The METRIC trial: A randomized international study of the antibody-drug conjugate glembatumumab vedotin (GV or CDX-011) in patients with metastatic gpNMB-overexpressing triple-negative breast cancer (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 OT1-03-15.

Abstract OT2-6-16: A pivotal multicenter, randomized, study evaluating the novel antibody-drug conjugate CDX-011 in patients with metastatic, triple-negative, high GPNMB over-expressing breast cancer

Background: GPNMB is an internalizable transmembrane glycoprotein overexpressed in multiple tumor types where it is a poor prognostic factor. Its functions appear to include mediating intercellular adhesion, promoting tissue repair, and regulating cell growth and differentiation. In tumor cell lines including breast cancer (BC), GPNMB enhances tumor growth and bone metastases. Relative to other BC subtypes, triple-negative BC (TNBC) highly over-expresses GPNMB in tumor epithelium where it correlates with a higher risk of recurrence. CDX-011 (glembatumumab vedotin) is a fully human GPNMB-specific monoclonal antibody drug conjugate combining the tumor-targeting GPNMB antibody with the potent cytotoxic microtubule inhibitor, monomethylauristatin E (MMAE). In the Phase II EMERGE study, 122 patients (pts) with heavily pre-treated BC (2-7 priors) and GPNMB-expression by IHC in ≥ 5% of either the tumor epithelial or stromal cells in archival tissue were randomized 2:1 to receive CDX-011 or “investigator's choice” (IC) single-agent chemotherapy, with crossover to CDX-011 permitted. CDX-011 as compared to IC, demonstrated higher objective response rates, with ORR of 8/25 (32%) vs 1/8 (13%) for high GPNMB expression (defined as expression in ≥25% of epithelial tumor cells) and 5/27 (19%) vs. 0/9 (0%) for TNBC. In the presence of both TNBC and high GPNMB, ORR was 4/12 (33%) vs 0/4 (0%) which corresponded to a doubling of median progression-free survival (PFS, p = 0.008) and median overall survival (OS, p = 0.003). CDX-011 was well tolerated with less hematologic toxicity (neutropenia: 29% vs 44%; leukopenia: 10% vs 27%; thrombocytopenia: 4% vs. 15%) but more rash (47% vs. 2%) and neuropathy (23% vs 12%) than IC. Methods: The current pivotal study aims to evaluate CDX-011 in metastatic GPNMB-over-expressing TNBC defined as ER and PR < 1%, HER2 negative (0-1+ IHC, or FISH ratio < 1.8). Eligibility criteria include >25% tumor epithelium GPNMB expression by central IHC; taxane and anthracyline resistance; ≤1 prior chemotherapy regimen for advanced BC; measurable disease by RECIST 1:1 and no persistent treatment-related toxicity of ≥ Grade 2 severity. 300 pts will be randomized (2:1) to receive CDX-011 (1.88 mg/kg IV q 21 days) or capecitabine (2500 mg/m2 daily for d1-14, q21 days) until progression or toxicity. Disease assessments are performed every six weeks for 6 months, and every 12 weeks thereafter. All pts are subsequently followed for survival. Endpoints are ORR and PFS (co-primary), duration of response, OS, safety, pharmacokinetics, and quality of life; tumor response assessments will be assessed by central review per RECIST 1.1. The trial has 80% power to detect a hazard ratio of 0.64 for PFS with α = 0.01 and/or a 30% increase in ORR (from 15% to 30%) with α = 0.04. For further information, contact info@celldextherapeutics.com.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT2-6-16.

Abstract P6-05-06: Association of HER2/neu single nucleotide polymorphism with trastuzumab-related cardiotoxicity

Background: Treatment with trastuzumab prolongs overall survival when given to patients (pts) with Her2/neu+ breast cancer (BC). The primary toxicity of trastuzumab is cardiotoxicity and the incidence is estimated at 2-4% in the adjuvant setting. The mechanism for trastuzumab-induced cardiotoxicity is not known. Although Her2neu expression is usually not seen on cardiac myocytes, its expression has been shown to be upregulated after chemotherapy. Trastuzumab is a monoclonal antibody that binds to the extracellular domain of Her2/neu. We hypothesized that single nucleotide polymorphisms (SNPs) in the Her2/neu receptor may play a role in trastuzumab associated cardiotoxicity.

Methods: 140 pts with BC who were treated with chemotherapy and trastuzumab were enrolled into an IRB approved protocol at the Weill Cornell Medical College between July 2008 and March 2013. Cardiotoxicity was defined as either symptomatic CHF, or a decline in LVEF of 15% (or if LVEF <55% a decline in LVEF of 10%) that required management with medications and led to temporary or permanent discontinuation of trastuzumab. 11 nonsynonomous human ErbB2 SNPs were identified in the National Center for Biotechnology Information SNP database (rs1136201, rs2172826, rs28933368, rs28933369, rs28933370, rs34602395, rs36085723, rs4252633, rs55943169, rs56366519, rs61552325). Genotyping of SNPs was performed on DNA prepared from blood or buccal washes. The relationship between SNP characteristics and cardiotoxicity status was assessed by the chi-square test and multivariable logistic regression analysis.

Results: 140 subjects (29 with cardiotoxicity and 111 without) had 11 SNPs sequenced. Median age of subjects was 56 years (range: 32-85), mean baseline LVEF was 65% (±6%). 16.4% of subjects had hypertension (HTN). 80% of patients were Caucasian, 10% East Asian, 7.1% African American, 2.9% South Asian. There were two SNPs for which there was variation seen among subjects: rs 1136201 (corresponding to codon 655) and rs61552325 (codon 1170). The frequencies of the codon 655 polymorphisms were: AA (Ile/Ile) 67.9%, AG (Ile/Val) 29.3%, and GG (Val/Val) 2.9%. The frequencies of the codon 1170 polymorphisms were: CC (Pro/Pro) 20.7%, GC (Ala/Pro) 45.7%, and GG (Ala/Ala) 33.6%. There was no association observed between the codon 655 polymorphism and cardiotoxicity (p = 0.96). A significant association between cardiotoxicity and the codon 1170 polymorphism was observed, with subjects having cardiotoxicity being more likely to carry the CC allele compared with subjects without cardiotoxicity (34.5% vs 17.1%, p = 0.04). This association persisted after multivariable adjustment for age, race, and HTN status (adjusted OR = 2.60, 95% CI = 1.02-6.62, p = 0.046).

Conclusion: In this study, the Her2/neu 1170 Pro/Pro polymorphism was associated with trastuzumab cardiotoxicity. If confirmed in a larger series, this polymorphism could be used to identify pts who may be at increased risk for cardiotoxicity and who may benefit from treatments associated with less cardiotoxicity. Furthermore, the Her2/neu 1170 SNP has previously been implicated as a minor histocompatibility antigen, and our findings raise the possibility that immune mediated mechanisms may play a role in trastuzumab related cardiotoxicity.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-05-06.

Tetrathiomolybdate-associated copper depletion decreases circulating endothelial progenitor cells in women with breast cancer at high risk of relapse

BACKGROUND

Bone marrow-derived endothelial progenitor cells (EPCs) are critical for metastatic progression. This study explores the effect of tetrathiomolybdate (TM), an anti-angiogenic copper chelator, on EPCs in patients at high risk for breast cancer recurrence.

PATIENTS AND METHODS

This phase 2 study enrolled breast cancer patients with stage 3 and stage 4 without evidence of disease (NED), and stage 2 if triple-negative. TM 100 mg orally was administered to maintain ceruloplasmin <17 mg/dl for 2 years or until relapse. The primary end point was change in EPCs.

RESULTS

Forty patients (28 stage 2/3, 12 stage 4 NED) were enrolled. Seventy-five percent patients achieved the copper depletion target by 1 month. Ninety-one percent of triple-negative patients copper-depleted compared with 41% luminal subtypes. In copper-depleted patients only, there was a significant reduction in EPCs/ml by 27 (P = 0.04). Six patients relapsed while on study, of which only one patient had EPCs maintained below baseline. The 10-month relapse-free survival was 85.0% (95% CI 74.6%-96.8%). Only grade 3/4 toxicity was hematologic: neutropenia (3.1% of cycles), febrile neutropenia (0.2%), and anemia (0.2%).

CONCLUSIONS

TM is safe and appears to maintain EPCs below baseline in copper-depleted patients. TM may promote tumor dormancy and ultimately prevent relapse.

Abstract P6-11-04: Targeting the tumor microenvironment: tetrathiomolybdate decreases circulating endothelial progenitor cells in women with breast cancer at high risk of relapse

Background: Bone marrow-derived endothelial progenitor cells (EPCs) constitute an important part of the tumor microenvironment and are critical for metastatic progression in preclinical models and breast cancer patients (Jain et al, Breast Cancer Res Treat, 2012). Tetrathiomolybdate (TM), a copper-depleting compound inhibits angiogenesis, tumor growth, and metastasis. This study explores the effect of TM on EPCs in patients at high risk for breast cancer recurrence.

Methods: This phase II study enrolled stage 3, 4 without evidence of disease (NED), and any node-positive triple negative breast cancer patient. Only concomitant hormone therapy was allowed. Patients received induction TM 180 mg daily at baseline followed by an equal or lower daily dose (median 100 mg, range 0–140) to maintain ceruloplasmin (Cp) level &lt; 17 mg/dl (target for copper depletion). We monitored EPCs (CD45dim/CD133+/VEGFR2+), Cp, CEA, and CA15-3 at baseline and monthly. Wilcoxon signed-rank was used to compare Cp and EPC levels between baseline and subsequent time points. All p-values were two-sided with statistical significance evaluated at the 0.05 alpha level.

Results: 50 patients (33 adjuvant, 17 Stage 4 NED, and 22 triple negative) were enrolled. In the first 40 patients enrolled who had received at least 24 months of TM, EPC and Cp data were available for analysis. Of these 40 patients, 1 patient did not take TM due to patient preference, and 736 cycles of TM (average 18.9 per patient) were administered. Median age was 50 years (range 29–66). Median number of tumor size and positive lymph nodes among adjuvant patients were 3.5 cm (range 1.2–7) and 9 (range 0–42), respectively. Of the patients receiving hormone therapy, 11 patients were on tamoxifen and 16 patients were on an aromatase inhibitor. Median baseline Cp level was 30 mg/dL (range 20–47). 71% patients adequately copper depleted at month 1 to a mean Cp of 14.8 mg/dL. A larger proportion of triple negative patients copper depleted (82%) compared to hormone receptor positive subtypes (47%) and HER2/neu positive subtypes (67%). Median EPCs/ml decreased from baseline to last dose by 16 in patients that achieved the copper depletion target, p = 0.014. Conversely, in patients that did not copper deplete, median EPCs/ml increased by 136, p = 0.005. Of the 50 patients on study, 7 patients relapsed in which a significant increase in EPCs preceded an objective clinical relapse and a tumor marker rise by a median of 1 month. Only grade 3/4 toxicity was hematologic, occurred in 49 cycles (6.7%), and resolved in 5–13 days with TM held and resumed at a lower dose.

Conclusions: TM is a well-tolerated oral copper chelator that may contribute to maintaining EPCs below baseline in copper-depleted patients. Molecular subtype may impact on the ability to copper deplete. EPCs may have potential as a surrogate marker for early relapse and as a therapeutic target for interrupting the metastatic progression.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-11-04.

Employment after a breast cancer diagnosis: a qualitative study of ethnically diverse urban women

Employment status is related to treatment recovery and quality of life in breast cancer survivors, yet little is known about return to work in immigrant and minority survivors. We conducted an exploratory qualitative study using ethnically cohesive focus groups of urban breast cancer survivors who were African-American, African-Caribbean, Chinese, Filipina, Latina, or non-Latina white. We audio- and video-recorded, transcribed, and thematically coded the focus group discussions and we analyzed the coded transcripts within and across ethnic groups. Seven major themes emerged related to the participants' work experiences after diagnosis: normalcy, acceptance, identity, appearance, privacy, lack of flexibility at work, and employer support. Maintaining a sense of normalcy was cited as a benefit of working by survivors in each group. Acceptance of the cancer diagnosis was most common in the Chinese group and in participants who had a family history of breast cancer; those who described this attitude were likely to continue working throughout the treatment period. Appearance was important among all but the Chinese group and was related to privacy, which many thought was necessary to derive the benefit of normalcy at work. Employer support included schedule flexibility, medical confidentiality, and help maintaining a normal work environment, which was particularly important to our study sample. Overall, we found few differences between the different ethnic groups in our study. These results have important implications for the provision of support services to and clinical management of employed women with breast cancer, as well as for further large-scale research in disparities and employment outcomes.

P1-03-02: The Norton-Simon Hypothesis and Cancer Stem Cells: How Cancer Stem Cells May Explain the Effectiveness of Dose-Dense Chemotherapy

Background: Systemic therapies are effective initially in controlling and reversing tumor growth; however, residual cancers will invariably re-grow despite this initial response. We have published data from paired human breast cancer samples that standard therapy every three weeks kills dividing daughter cells but not tumor-initiating cells (TICs), so that samples obtained after therapy are enriched for CD44+/CD24−/low putative “tumor-initiating” or “cancer stem” cells, indicating that standard treatment regimens are missing the critical targets, TICs. Interestingly, we have recent data in human breast tumors that indicate that TICs may in fact be chemosensitive initially, with a decrease in TICs observed within two days of chemotherapy, but shortly thereafter, TICS are actually induced by chemotherapy.

Materials and Methods: To evaluate TICs response to chemotherapy, mice with human breast tumor xenograft lines BCM-2665a and BCM-2147 were treated with vehicle, 10-, or 33-mg/kg docetaxel, and then tumors were collected for TIC assays and molecular analysis at both 48 and 72h after treatment. Using Affymetrix gene expression microarrays and reverse phase protein array (RPPA) analysis with 119 different validated antibodies, we identified pathways involved in regulation of TICs. Results: According to flow cytometric analysis for TIC markers and mammosphere (MS) formation efficiency, BCM-2665 TICs were reduced by docetaxel treatment compared to vehicle-treated at 48h post 10 mg/kg docetaxel (4-fold decrease) and 48 and 72h post 33 mg/kg docetaxel compared to control (14- and 2-fold decrease, respectively). Although the BCM-2147 TICs did not significantly decrease at any time points or doses tested, they were clearly induced at 72h post-treatment compared to control. Additionally, BCM-2665 TICs were increased within 72h post 10 mg/kg docetaxel, indicating that these time points are ideal for defining the mechanisms responsible for induction of TICs. Ingenuity Pathway Analysis of Affymetrix microarray data for both BCM-2665 and BCM-2147 revealed induction of inflammatory pathways, suggesting leukocyte infiltration associated with induction of TICs. Furthermore, RPPA analysis confirmed gene expression changes from the microarray data, and implicated apoptosis and inflammatory pathways. Sixteen of 28 proteins significantly changed with activation of CSC are involved in development of leukocytes. Discussion: These findings are consistent with the Norton-Simon Hypothesis in that chemotherapy regimens given more frequently may in fact eliminate TICs, thereby explaining the proven increased effectiveness of dose-dense chemotherapy. Based on when TICs became chemoresistant, we are comparing dose-dense treatment (4 mg/kg docetaxel every 3 days) to a traditional single dose of 32 mg/kg, in an effort to eliminate the tumor cells that cause tumor recurrence. Furthermore, our analysis of gene expression at both the RNA and protein level implicated the immune cells as TICs inducers. Since our immunocompromised mice lack T- and B- cells but have active macrophages, macrophages are indicated as inducers of TICs. We are focusing our current efforts at identifying how immune cells activate TICs and thus enhance tumorigenesis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-03-02.

Impact of eribulin on overall survival in patients with metastatic breast cancer with visceral disease

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Background: Visceral disease is associated with poor survival outcome in women with metastatic breast cancer (mBC). Eribulin mesylate is a nontaxane microtubule dynamics inhibitor indicated for 3rd-line monotherapy in patients (pts) with mBC previously treated with at least two chemotherapeutic regimens in the metastatic setting, including an anthracycline and a taxane.

Methods: Evidence from the global, randomized, multicenter, phase III clinical trial of eribulin in mBC (EMBRACE) demonstrated improved overall survival (OS) for eribulin-treated pts when compared to treatment of physician’s choice (TPC). In this unplanned subgroup analysis, we compare the clinical benefit of eribulin to TPC in mBC pts with visceral disease using the Independent Review database. Patients were categorized as having visceral disease if they had target or non-target lesion involvement in the adrenal gland, liver, lung, pleural, pericardial/peritoneal cavity, spleen, or thyroid. Patients with brain metastases were excluded from the trial.

Results: EMBRACE enrolled 762 pts with mBC, with single organ disease present in 120 pts (15.7%). The remaining pts had multi-organ disease. A total of 81.9% (624) of pts were classified as having visceral disease–81.3% (413) randomized to receive eribulin and 83.1% (211) to receive TPC. Metastatic tumor site was similar in eribulin and TPC arms, with liver (58.3%; 62.6%), lung (38.8%; 37.4%) and pleural (17.1%; 16.5%) involvement. Patients with visceral disease treated with eribulin demonstrated a significant benefit in OS compared to TPC (HR 0.77, p=0.02). Median OS in mBC pts with visceral disease was 12.45 months (mos) for eribulin-treated pts, with ORR=11.0% and CBR*=21.7% compared to OS=10.12 mos, ORR=5.0%, CBR*=16.6% for TPC-treated patients (*CBR defined as CR+PR+SD>6mos). No significant treatment difference was observed in the non-visceral disease patients however due to the small number of patients with non-visceral disease, no robust statistical conclusions can be made.

Conclusions: Treatment with eribulin resulted in significant improvement in overall survival for mBC pts with visceral disease compared to other commonly used chemotherapeutic agents.

Treatment of metastatic breast cancer: second line and beyond

Increasing use of standard chemotherapy, especially anthracycline- and taxane-based therapies, in early-stage breast cancer has led to a corresponding increase in heavily pretreated and/or treatment-resistant cases of metastatic breast cancer (MBC). Thus, second and later lines of MBC therapy frequently involve the clinically challenging picture of progressive disease and limited treatment options. While several prognostic factors have been identified to aid treatment selection in MBC patients, treatment is palliative and aimed at prolonging survival, controlling symptoms, and maximizing patients' quality of life. No globally accepted standard exists for meeting these goals, and treatment patterns vary according to region. The list of available agents for the treatment of MBC is increasing with newer chemotherapeutic agents and molecular-targeted therapies. Within recent years, several single-agent and combination chemotherapy regimens have been shown to improve progression-free survival and reduce symptoms of disease in clinical studies in patients with resistant and/or heavily pretreated MBC. However, at present, the demonstrated benefits of these medical interventions have usually not included extension of overall survival times. It is hoped that in the near future, ongoing refinements to treatment approaches used in second-line settings and beyond will allow meaningful improvements in symptom control and survival in MBC.

A phase III study (EMBRACE) of eribulin mesylate versus treatment of physician's choice in patients with locally recurrent or metastatic breast cancer previously treated with an anthracycline and a taxane

CRA1004^

Background: Eribulin mesylate (E7389; E) is a nontaxane microtubule dynamics inhibitor with a novel mode of action. This study is the first to compare overall survival (OS) with this new chemotherapeutic (CT) agent to real-life choices in heavily pretreated patients (pts) with metastatic breast cancer (MBC).

Methods: Women with locally recurrent or MBC were enrolled in this phase III open-label, randomized, multicenter study. Pts had received 2-5 prior CT (≥2 for advanced disease), including an anthracycline and a taxane, unless contraindicated. Pts were randomized 2:1 to E 1.4 mg/m2 2-5 min IV bolus on days 1 and 8 of a 21-day cycle or treatment of physician's choice (TPC). TPC was any monotherapy (cytotoxic, hormonal, biologic) or supportive care only. The primary endpoint was OS; secondary endpoints were objective response rate (ORR), and progression-free survival (PFS) by independent review, and duration of response (DOR). Safety and tolerability were assessed. Data are from the final analysis after 422 deaths.

Results: 762 pts were treated (508 E, 254 TPC). Median age was 55.2 (range 27-85), 16% were HER2-positive, 19% triple-negative, 73% received prior capecitabine, median no. of prior CT was 4. Median OS was 13.1 months (mo) for E vs. 10.7 mo for TPC, p=0.04 (primary analysis, stratified log rank test; HR 0.81; 95% CI 0.66, 0.99). Median PFS was 3.7 mo for E and 2.3 mo for TPC p=0.09 (HR 0.85; 95% CI 0.70, 1.03). ORR was 12% (0.4% complete response [CR], 11.5% partial response [PR]) for E and 5% (0 CR; 5% PR) for TPC, p=0.005. Median DOR was 4.1 mo for E (56 responders) vs. 6.7 mo for TPC (11 responders). Grade [G] 3/4 treatment-related adverse events (AEs) of interest for E were asthenia/fatigue (7.6%), neutropenia (44%), peripheral neuropathy (8.4%). 10% of pts experienced treatment-related serious AEs (12% E, 7% TPC).

Conclusions: The study met its primary endpoint with a significant improvement in OS by a median of 2.5 mo with E vs. TPC. E demonstrated a manageable tolerability profile, acceptable for a CT agent used as monotherapy in this late-line setting.

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In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519-521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2010 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .

Phase II study of sagopilone (ZK-Epo) in patients with recurrent metastatic breast cancer (MBC)

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Background: Sagopilone is a novel, fully synthetic epothilone, which represents a new class of microtubule stabilizing agents. It has shown significant pre-clinical activity in taxane resistant breast cancer cell lines and in tumor models, as well as clinical activity in both taxane naïve and pretreated MBC. Methods: MBC patients who received ≤ 3 prior anthracycline and taxane containing chemotherapies were eligible. Sagopilone was given either at 16 mg/m2 (arm A) or at 22 mg/m2 (arm B, amended additional cohort) IV over 3 hours every 21 days for up to 6 cycles. The primary end point was tumor response by RECIST. The Simon 2-Stage design required 3 responders in the first 24 evaluable patients in stage 1 and 10 responders in 65 evaluable patients to declare success. Results: Between June 2006 and June 2008, 65 patients were enrolled and treated (39 in arm A, 26 in arm B). Majority of metastases were in lymph nodes (62%), liver (55%), bone (49%), lung (37%), and cutaneous sites (19%). Median number of cycles delivered was 2 (1–17). Neither arm met Stage 1 criteria for responders. Nevertheless, 2 patients in arm A and 1 in arm B had confirmed partial response, and lasted 4, 7, and 2 months, respectively. 26% patients in arm A, and 42% in arm B had stable disease. 42 patients discontinued study prior to cycle 6 due to progressive disease/death, 14 due to adverse events, and 1 due to other reasons. All 65 patients are evaluable for safety. Adverse events documented or reported in ≥ 20% patients are: sensory neuropathy 80% (23% grade 3), nausea 57% (no grade 3), fatigue 45% (12% grade 3), vomiting 29% (no grade 3), myalgia 28% (5% grade 3), diarrhea 25% (2% grade 3), insomnia 25% (no grade 3), pain in extremity 25% (2% grade 3), headache 23% (5% grade 3), arthralgia 22% (5% grade 3), constipation 22% (2% grade 3). Conclusions: Sagopilone had limited activity in these heavily pretreated MBC patients. It appeared tolerable at both dose levels.

[Table: see text]

Phase II trial of the farnesyltransferase inhibitor tipifarnib plus fulvestrant in hormone receptor-positive metastatic breast cancer: New York Cancer Consortium Trial P6205

BACKGROUND

Fulvestrant produces a clinical benefit rate (CBR) of approximately 45% in tamoxifen-resistant, hormone receptor (HR)-positive metastatic breast cancer (MBC) and 32% in aromatase inhibitor (AI)-resistant disease. The farnesyltransferase inhibitor tipifarnib inhibits Ras signaling and has preclinical and clinical activity in endocrine therapy-resistant disease. The objective of this study was to determine the efficacy and safety of tipifarnib-fulvestrant combination in HR-positive MBC.

PATIENTS AND METHODS

Postmenopausal women with no prior chemotherapy for metastatic disease received i.m. fulvestrant 250 mg on day 1 plus oral tipifarnib 300 mg twice daily on days 1-21 every 28 days. The primary end point was CBR.

RESULTS

The CBR was 51.6% [95% confidence interval (CI) 34.0% to 69.2%] in 31 eligible patients and 47.6% (95% CI 26.3% to 69.0%) in 21 patients with AI-resistant disease. A futility analysis indicated that it was unlikely to achieve the prespecified 70% CBR. Tipifarnib dose modification was required in 8 of 33 treated patients (24%).

CONCLUSIONS

The target CBR of 70% for the tipifarnib-fulvestrant combination in HR-positive MBC was set too high and was not achieved. The 48% CBR in AI-resistant disease compares favorably with the 32% CBR observed with fulvestrant alone in prior studies and merit further clinical and translational evaluation.

The effect of tetrathiomolybdate on circulating endothelial progenitor cells in patients with breast cancer at high risk of recurrence

Abstract #1036

Background: Endothelial progenitor cells are critical to tumor angiogenesis and are increased in breast cancer patients. Copper is required for angiogenesis, and pre-clinical data suggest that tetrathiomolybdate (TM), a copper-depleting compound, inhibits angiogenesis and maintains tumor dormancy. We sought to measure circulating endothelial progenitor cells (CEPCs) in patients at high risk of breast cancer recurrence and to evaluate the effect of copper depletion on CEPCs.&#x2028; Methods: This analysis is part of an ongoing phase II study of TM in breast cancer patients at high risk of recurrence defined as Stage III or IV with no evidence of disease. All therapy other than hormonal was completed at least 6 weeks prior to study. Treatment: TM 180 mg daily to achieve a target ceruloplasmin (Cp) level of 5-15 mg/dL (copper depletion), and then 100 mg daily. We monitored levels of CEPCs (CD45dim, CD133+, VEGFR2+), CEA, CA15-3, and Cp at baseline and monthly. CEPCs were also measured in 6 healthy controls.&#x2028; Results: To date we have enrolled 16 patients with a median age of 51 years (range: 29-64). 14 had a history of Stage III disease, while 2 were considered to be Stage IV with no evidence of disease. The median number of positive lymph nodes among Stage III patients was 7 (1-42), with 2 patients having received neoadjuvant therapy. The median baseline Cp level was 28 mg/dL (21-41). Among 12 patients who have reached target Cp, the median time to target was 1 month (1-3 months). The median follow-up of the 4 patients who have not yet achieved target is 2.5 months. 1 of these discontinued treatment before reaching target. The median baseline CEPCs was lower in patients than healthy controls: 0.022 cells/μL (0.000-0.286) vs. 0.123 cells/μL (0.058-0.418); p=0.03. There was no statistically significant change in CEPCs from baseline over time.&#x2028; One patient was diagnosed with recurrent breast cancer at month 10. A rise in her CEPCs preceded a rise in a CEA and overt relapse by 1 and 5 months, respectively.&#x2028; Toxicity: Grade 3/4 neutropenia occurred in 3 patients. TM was held, and this resolved 5-13 days later, after which TM was resumed. No other grade 3/4 toxicity was observed. One patient discontinued TM due to diarrhea attributed to the lactose used in the compounding of TM.&#x2028; Conclusions: TM is well tolerated in breast cancer patients. We postulate that the increased CEPCs noted in one patient at month 4, 6 months prior to overt relapse, could represent the “turning on” of an angiogenic switch, resulting in an outpouring of CEPCs to the new site of metastasis. The trial is ongoing, and with additional follow-up other trends might emerge.&#x2028; Supported by Komen for the Cure Foundation, Anbinder Foundation, NY Community Trust and Breast Cancer Alliance of Greenwich.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1036.

Phase II study of the farnesyl transferase inhibitor tipifarnib plus fulvestrant in postmenopausal patients with hormone receptor-positive breast cancer: New York Cancer Consortium Trial P6205

1037

Background: Tipifarnib and fulvestrant both have single agent activity in hormone receptor-positive (HR+) metastatic breast cancer (MBC), and tipifarnib enhances the activity of anti-estrogens in HR+ breast cancer cell lines. Methods: Eligibility criteria: measurable HR+ MBC, postmenopausal status, ECOG PS of 0–2, and no prior chemotherapy for MBC. Treatment: fulvestrant 250 mg IM on day 1 plus oral tipifarnib 300 mg BID on days 1–21 every 28 days (defined as one cycle). Response was evaluated by RECIST criteria every 3 cycles. The study was suspended for efficacy/futility analysis after 33 of 46 patients were accrued. It was designed to detect an improvement in clinical benefit rate (CBR; defined as objective response or stable disease for at least 24 weeks) from 50% to 70% (90% power, type I error 10%), and would require at least 26 of 42 eligible/evaluable patients to have clinical benefit (CB). The expected CBR for fulvestrant alone is 30% in aromatase inhibitor (AI) resistant disease (Ingle, 2006), 45% in tamoxifen (tam)-resistant disease (Osborne, 2002), and 60% when used as first line endocrine therapy (ET) (Howell, 2004). Results: Of 33 patients enrolled, 28 are currently assessable for CBR (2 were ineligible, and 3 have stable disease for < 6 months and remain on treatment). Grade 3/4 toxicity: neutropenia (15%), pain (11%) and gastrointestinal toxicity (11%). Tipifarnib was either reduced in dose (N=10) or discontinued (N=8) due to toxicity or non-compliance. The overall CBR is shown; should accrual continue, all 14 evaluable patients must have CB in order to meet the pre-specified efficacy objective. For the ET-resistant group, 18 were resistant to AI therapy (or AI plus tam in 5) and 2 to tam. * Number eligible/evaluable for CBR. Conclusions: The tipifarnib-fulvestrant combination is not likely to produce a CBR of at least 70%. The 45% CBR in ET-resistant disease may merit further evaluation in this setting.

[Table: see text]

No significant financial relationships to disclose.

Phase III trial of ixabepilone plus capecitabine compared to capecitabine alone in patients with metastatic breast cancer (MBC) previously treated or resistant to an anthracycline and resistant to taxanes

1006

Background: Patients with MBC who have progressed after anthracyclines and taxanes have limited treatment options. Ixabepilone, a novel epothilone B analog, is active in resistant breast cancer. Methods: In this large multinational phase III trial, patients with MBC who were anthracycline pretreated and met predefined resistance criteria to taxanes were randomized to ixabepilone (40mg/m2 IV over 3h Q3w) + capecitabine (1,000mg/m2 PO BID Q14d) or capecitabine (1,250mg/m2 PO BID Q14d). The primary endpoint was progression-free survival (PFS); secondary endpoints included objective response rate (ORR), safety, and overall survival (available after 2007). Response and progression were assessed by an independent review committee (IRC) and the investigators (INV). Results: 752 patients were randomized. Median age was 53; 84% had visceral disease, 48% and 43% had 1 and =2 prior metastatic regimens. Median of 5 and 4 cycles of ixabepilone + capecitabine and capecitabine were administered. Ixabepilone + capecitabine was superior to capecitabine. Significant benefit was consistently maintained across predefined subgroups, including HER2-/ER- /PR- and HER2+. *Primary analysis of PFS; hazard ratio= 0.75. Grade (G) 3/4 adverse events included neuropathy (ixabepilone + capecitabine 23% vs capecitabine 0%), hand-foot syndrome (18% vs 17%), and fatigue (9% vs 3%). Neuropathy was cumulative and reversible (median time to resolution of G3/4 to baseline/G1 was 6 weeks). G3 and 4 neutropenia were reported in 32% and 36% vs 9% and 2%, respectively; febrile neutropenia was 5% with ixabepilone + capecitabine. Toxic death rate was 3% vs 1%. Patients with liver dysfunction were at greater risk. Conclusions: Ixabepilone + capecitabine has superior efficacy to capecitabine across endpoints and has a manageable safety profile in this heavily pretreated population. It offers a new potential option for patients with MBC.

[Table: see text]

No significant financial relationships to disclose.

Randomized trial of low-dose interleukin-2 vs cyclosporine A and interferon-γ after high-dose chemotherapy with peripheral blood progenitor support in women with high-risk primary breast cancer

High-risk primary breast cancer patients treated with high-dose chemotherapy (HDC) and stem cell support (SCS) have shown prolonged disease-free survival (DFS) in many studies; however, only one trial has demonstrated an overall survival benefit (OS). We hypothesize that the period following myeloablative therapy is ideal for immunologic manipulation and studied the effects of two different methods of immunotherapy following HDC with SCS aimed at the window of immune reconstitution. Seventy-two women with high-risk stage II or III breast cancer were randomized following HDC to receive either interleukin 2 (IL-2) at 1 million units/m(2) SQ daily for 28 days or combined cyclosporine A (CsA) at 1.25 mg/kg intravenously daily from day 0 to +28 and interferon gamma (IFN-gamma) 0.025 mg/m(2) SQ every 2 days from day +7 to +28. At a median follow-up of 67 months, no significant difference was observed in DFS or OS between the two treatment groups. The IL-2 arm had a 59% DFS (95% CI (0.45, 0.78)) and a 72% OS (95% CI (0.58, 0.88)) at 5 years. The CsA/INF-gamma arm had a similar outcome with a 55% DFS (95% CI (0.40, 0.76)) and a 78% OS (95% CI (0.65, 0.94)) at 5 years. Treatment was well tolerated, without increased toxicity.

Phase I/II trial in patients with metastatic breast cancer (MBC) previously treated with a taxane and an anthracycline: Final safety data

10528

Background: Ixabepilone, a semi-synthetic analog of the natural product epothilone B, has shown anti-tumor activity in a broad range of tumor types including breast cancer. Preclinical studies suggest synergy between ixabepilone and capecitabine in breast cancer models and has fuelled interest in the clinical setting. Methods: This open-label Phase I/II study was conducted to determine the recommended Phase II (and III) doses of ixabepilone and capecitabine using a 3-hour infusion of ixabepilone given on Day 1 (Schedule A) or a 1-hour infusion of ixabepilone given for 3 days (Schedule B) in combination with capecitabine given orally on Days 1–14 every 21 days in patients (pts) with MBC previously treated with a taxane and an anthracycline. Eligible pts were aged ≥18 years with pathologic diagnosis of breast cancer and evidence of MBC, who had received prior treatment with a taxane and an anthracycline in the adjuvant or metastatic setting. Pts were excluded if they had received >3 prior chemotherapy regimens in the metastatic setting or had ≥Grade 2 neuropathy. Toxicity was continuously monitored using NCI CTC v2. Results from the 62 pts treated with 40 mg/m2 as a 3 hr-infusion ixabepilone and 2000 mg/m2 capecitabine are shown here. Results: 56 of the 62 pts (90%) were aged <65 years. 80% of pts had visceral disease; 44% were ER/PR/HER-2 negative. 44% of pts had received ≥ two prior chemotherapies in the metastatic setting. Grade 3 neuropathy (sensory and motor) was reported in 12 pts and 1 pt (19%, 2%), respectively. Hand-foot syndrome, reported in 39 pts (63%), was primarily Grade 2 (26%) or 3 (34%). Hematologic toxicities included Grade 4 leukopenia (7 pts, 12%) and Grade 4 neutropenia (16 pts, 26%). Dose reductions were used to manage sensory neuropathy and hematologic abnormalities. Conclusions: The recommended Phase II (and III) doses are 40 mg/m2 ixabepilone (3-hour infusion on Day 1 every 21 days) and 2000 mg/m2 capecitabine (divided BID on Days 1–14 every 21 days). This ixabepilone/capecitabine combination demonstrated a manageable safety profile and promising clinical anti-tumor activity in pts with MBC previously treated with a taxane and an anthracycline.

[Table: see text]

Phase I/II study of tandem cycles of high-dose chemotherapy followed by autologous hematopoietic stem cell support in women with advanced ovarian cancer

The objectives of this study were to investigate the tolerability of a novel high-dose chemotherapy (HDC) regimen with peripheral blood progenitor cell (PBPC) support in patients with pretreated advanced ovarian cancer and to determine the maximum-tolerated dose (MTD) of topotecan in this setting. Advanced ovarian cancer patients previously treated with platinum-based first-line therapy were enrolled. After PBPC mobilization and harvesting, patients received three consecutive cycles of HDC with PBPC support. Cycle 1 was carboplatin area under the concentration curve 20 and paclitaxel 250 mg/m(2). Cycle 2 was topotecan starting at 5 mg/m(2), dose escalated in 2 mg/m(2) increments, and etoposide 600 mg/m(2). Cycle 3 was thiotepa 500 mg/m(2). After each cycle, PBPCs were infused. Granulocyte colony stimulating factor (5 microg/kg/day) was administered until neutrophil recovery occurred. Seventeen patients were enrolled; all were safety evaluable. The most common nonhematologic toxicity was grade 3 mucositis (44%). Engraftment of PBPCs was successful in all patients after each cycle, and no treatment-related deaths occurred. Of 14 patients with measurable disease, 5 (36%) had complete responses, 2 (14%) had partial responses, and 4 (29%) had stable disease. The median progression-free and overall survivals were 7 and 18 months, respectively. The MTD of topotecan was not reached. The tolerability and activity of this regimen in patients with advanced ovarian cancer warrant further investigation.

Glutamine as a Neuroprotective Agent in High-dose Paclitaxel-induced Peripheral Neuropathy: A Clinical and Electrophysiologic Study

AIMS

The appearance of peripheral neuropathy is the dose-limiting toxicity in many chemotherapy protocols, and glutamine has been proposed as a potentially neuroprotective agent in patients receiving paclitaxel.

MATERIALS AND METHODS

In this non-randomised study, we assessed neurologic signs and symptoms, and changes in nerve-conduction studies in 46 consecutive patients given high-dose paclitaxel either with (n=17) or without (n=29) glutamine. Neurological assessments and electrodiagnostic studies were carried out at baseline and at least 2 weeks (median 32 days) after treatment.

RESULTS

Patients who received glutamine developed significantly less weakness (P = 0.02), less loss of vibratory sensation (P = 0.04) and less toe numbness (P = 0.004) than controls. The per cent change in the compound motor action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes after paclitaxel treatment was lower in the glutamine group, but this finding was not statistically significant in these small groups.

CONCLUSIONS

In this study, serial neurologic assessment of patient symptoms and signs seemed to be a better indicator of a possible glutamine effect than sensory- or motor-nerve-conduction studies. Prospective randomised trials are needed to clarify the effect of glutamine on paclitaxel and other types of chemotherapy-induced neuropathy.

Phase II trial of sequential high-dose chemotherapy with paclitaxel, melphalan and cyclophosphamide, thiotepa and carboplatin with peripheral blood progenitor support in women with responding metastatic breast cancer

A single high-dose cycle of chemotherapy can produce response rates in excess of 50%. However, disease-free survival (DFS) is 15-20% at 5 years. The single most important predictor of prolonged DFS is achieving a complete response (CR). Increasing the proportion of patients who achieve a complete response may improve disease-free survival. Women with metastatic breast cancer and at least a partial response (PR) to induction chemotherapy received three separate high-dose cycles of chemotherapy with peripheral blood progenitor support and G-CSF. The first intensification was paclitaxel (825 mg/m(2)), the second melphalan (180 mg/m(2)) and the third consisted of cyclophosphamide 6000 mg/m(2) (1500 mg/m(2)/day x 4), thiotepa 500 mg/m(2) (125 mg/m(2)/day x 4) and carboplatin 800 mg/m(2) (200 mg/m(2)/day x 4) (CTCb). Sixty-one women were enrolled and 60 completed all three cycles. Following the paclitaxel infusion most patients developed a reversible, predominantly sensory polyneuropathy. Of the 30 patients with measurable disease, 12 converted to CR, nine converted to a PR*, and five had a further PR, giving an overall response rate of 87%. The toxic death rate was 5%. No patient progressed on study. Thirty percent are progression-free with a median follow-up of 31 months (range 1-43 months) and overall survival is 61%. Three sequential high-dose cycles of chemotherapy are feasible and resulted in a high response rate. The challenge continues to be maintenance of response and provides the opportunity to evaluate strategies for eliminating minimal residual disease.

The pharmacokinetics and pharmacodynamics of high-dose paclitaxel monotherapy (825 mg/m2 continuous infusion over 24 h) with hematopoietic support in women with metastatic breast cancer

PURPOSE

We evaluated the pharmacokinetics and pharmacodynamics of high-dose paclitaxel (HDP) monotherapy (825 mg/m2 continuous infusion over 24 h) with peripheral blood progenitor cell (PBPC) and G-CSF support in 17 women with metastatic breast cancer.

METHODS

Pharmacokinetic and pharmacodynamic data were collected in 17 women entered in a phase II trial of sequential HDP, and high-dose melphalan and cyclophosphamide/thiotepa/carboplatin.

RESULTS

The maximal plasma concentration (Cmax), area under the plasma concentration time curve (AUC), apparent clearance (Clapp), duration of plasma concentration above 0.05 microM (t > 0.05 microM) for paclitaxel were (means SD): 9.11 +/- 7.45 microM, 145 +/- 88 microM x h, 8.06 +/- 2.90 l/h per m2 and 82.4 +/- 31.2 h, respectively. There was a significant correlation between the plasma paclitaxel concentration at 1 h (r2 = 0.87), 12 h (r2 = 0.85) and 23 h (r2 =0.92) and the AUC (P < 0.0001). Duration of neutropenia was brief (median 3 days, range 0-5 days) and neutrophil recovery occurred earlier (median 6 days, range 0-7 days) than could be attributed to infused PBPC. Median nadir count for platelets was 66 x 10(9)/l (range 13-160 x 10(9)/l). Pharmacodynamic analysis showed no correlation between pharmacokinetic parameters (Cmax, AUC, t > 0.05 microM) and time to neutropenic nadir, duration of neutropenia, platelet count nadir and grades of neuropathy or mucositis. In ten patients in whom detailed neurologic and nerve conduction studies were performed, linear regression analysis showed a significant correlation between pre- and post-HDP treatment total neuropathy scores (r2 = 0.46, P = 0.03).

CONCLUSIONS

HDP (825 mg/m2 continuous infusion over 24 h) did not appear to be myeloablative. The degree of neurotoxicity subsequent to HDP was associated with the degree of baseline neuropathy but was not predictable from pharmacokinetic parameters.

Bilateral facial nerve palsy secondary to the administration of high-dose paclitaxel

Bilateral facial nerve palsy is an uncommon occurrence. We describe a case of bilateral facial nerve palsy secondary to a single cycle of high-dose paclitaxel therapy (825 mg/m2), in a woman with breast cancer. Prior to her high-dose therapy, she had a residual grade 2 peripheral neuropathy following treatment with ten cycles of standard-dose paclitaxel (total dose 3200 mg). The features of the peripheral neuropathy due to standard-dose paclitaxel, which can be both motor and sensory, are well described. Cumulative paclitaxel dose is considered a risk factor for development of the neuropathy. Although facial nerve palsy secondary to paclitaxel is not previously reported, other cranial nerve toxicity has been described. Consistent with reports of the reversibility of paclitaxel-induced peripheral neuropathy, the facial nerve palsies in our patient resolved over 23 months. Ongoing studies of high-dose paclitaxel warrant close attention to its cumulative neurotoxic effects, particularly in patients previously treated with neurotoxic chemotherapy.

A phase I study of high-dose BCNU, etoposide and escalating-dose thiotepa (BTE) with hematopoietic progenitor cell support in adults with recurrent and high-risk brain tumors

This phase I dose-escalation study was performed to determine the tolerability of three-drug combination high-dose BCNU (B) (450 mg/m2), escalating-dose thiotepa (500-800 mg/m2) and etoposide (1200 mg/m2) in divided doses over four days in 22 adults with malignant primary brain tumors. Patients received G-CSF and hematopoeitic support with peripheral blood progenitor cells (PBPC) (n = 18) or both PBPC and marrow (n = 4). The maximum tolerated dose of thiotepa with acceptable toxicity was determined as 800 mg/m2. The 100-day mortality rate was 9% (2/22). Grade III/IV toxicities included mucositis (71%), diarrhea (29%), nausea/vomiting (19%), and hepatic toxicity (14%). Neurological toxicities occurred in 24% and included seizures (two patients) and encephalopathy (three patients). Encephalopathy was transient in two patients and progressive in one patient. All patients had neutropenic fever. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 10 days (range 8-30 days). Platelet engraftment >20 x 10(9)/l occurred after 11 days (range 9-65 days). In the eighteen patients supported solely with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.78, p = 0.001) and platelet engraftment (rho = -0.76, p = 0.002). Overall, 11% of evaluable patients (2/18) had a complete response to BTE. Median time to tumor progression (TTP) was 9 months, with an overall median survival of 17 months. BCNU (450 mg/m2), thiotepa (800 mg/m2) and etoposide (1200 mg/m2) in divided doses over four days is a tolerable combination HDC regimen, the efficacy of which warrants further investigation in adults with optimally resected chemoresponsive brain tumors.

CD34+ cell dose requirements for rapid engraftment in a sequential high-dose chemotherapy regimen of paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin (CTCb) with PBPC support in metastatic breast cancer

Sequential high-dose chemotherapy may increase the threshold dose of CD34+ cells necessary for rapid and successful hematologic recovery. There are limited data regarding the pharmacodynamics and threshold CD34+ cell dose required for engraftment following high-dose paclitaxel. To determine the dose of CD34+ PBPC sufficient for rapid engraftment, 65 women with metastatic breast cancer undergoing a sequential high-dose paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin (CTCb) chemotherapy regimen were evaluated. The intertreatment interval was a median of 27 days. Paclitaxel was escalated from 400 to 825 mg/m2, infused continuously (CI) over 24 h on day -4 with PBPC reinfusion on day 0. Following marrow recovery, 90 mg/m2/day of melphalan was given over 30 min on days -2 and -1, with PBPC reinfusion on day 0. On recovery, patients received CTCb on days -7 to -3, with PBPC reinfusion on day 0. G-CSF was administered after each cycle until WBCC recovery. For paclitaxel, an ANC >0.5 x 10(9)/L occurred at a median of 6 days (range 0-7 days) after PBPC reinfusion. The median nadir platelet count was 63 x 10(9)/L (range 6 x 10(9)/L-176 x 10(9)/L). Eight patients (12%) had platelet nadir <20 x 10(9)/L, and all recovered their counts to >20 x 10(9)/L on day 7. There was no clinical difference in days to engraftment between women receiving <2 or > or =2 x 10(6) CD34+ PBPC/kg following paclitaxel. All patients recovered neutrophil and platelet counts within 7 days after reinfusion of > or =1 x 10(6) CD34+ cells/kg and G-CSF. The data suggest that a paclitaxel dose of 825 mg/m2 is not myeloablative. For melphalan, median days to ANC >0.5 x 10(9)/L was 10 days (range 9-15), and platelet recovery to >20 x 10(9)/L was 13 days (range 0-28) after PBPC reinfusion. Median time to engraftment was more rapid in patients receiving > or =2 x 10(6) CD34+/kg versus <2 x 10(6)CD34+/kg, for both neutrophils (11 days versus 10 days, p = 0.05) and platelets (14 days versus 12 days, p < 0.01). Ninety-eight percent of patients infused with > or =2 x 10(6) CD34+/kg engrafted within 21 days. Following CTCb in this sequential regimen, a dose of > or =2 x 10(6) CD34+ cells/kg provided for significantly more rapid neutrophil engraftment than <2 x 10(6) CD34+ cells/kg (9 days versus 10 days,p = 0.01), but a dose > or =3 X 10(6) CD34+ cells/kg is necessary for reliable, rapid, and sustained neutrophil and platelet engraftment by day 21.

High-dose thiotepa and etoposide-based regimens with autologous hematopoietic support for high-risk or recurrent CNS tumors in children and adults

The prognosis in patients with primary brain tumors treated with surgery, radiotherapy and conventional chemotherapy remains poor. To improve outcome, combination high-dose chemotherapy (HDC) has been explored in children, but rarely in adults. This study was performed to determine the tolerability of three-drug combination high-dose thiotepa (T) and etoposide (E)-based regimens in pediatric and adult patients with high-risk or recurrent primary brain tumors. Thirty-one patients (13 children and 18 adults) with brain tumors were treated with high-dose chemotherapy: 19 with BCNU (B) and TE (BTE regimen), and 12 with carboplatin (C) and TE (CTE regimen). Patients received growth factors and hematopoietic support with marrow (n = 15), peripheral blood progenitor cells (PBPC) (n = 11) or both (n = 5). The 100 day toxic mortality rate was 3% (1/31). Grade III/IV toxicities included mucositis (58%), hepatitis (39%) and diarrhea (42%). Five patients had seizures and two had transient encephalopathy (23%). All patients had neutropenic fever and all pediatric patients required hyperalimentation. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 11 days (range 8-37 days). Time to ANC engraftment was significantly longer (P = 0.0001) in patients receiving marrow (median 14 days, range 10-37) than for PBPC (median 9.5 days, range 8-10). Platelet engraftment >50 x 10(9)/l was 24 days (range 14-53 days) in children. In adults, platelet engraftment >20 x 10(9)/l was 12 days (range 9-65 days). In 11 patients supported with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.87, P = 0.009) and platelet engraftment (rho = -0.85, P = 0.005), with CD34+ dose predicting time to engraftment following HDC. Overall, 30% of evaluable patients (7/24) had a complete response (CR) (n = 3) or partial response (PR) (n = 4). Median time to tumor progression (TTP) was 7 months, with an overall median survival of 12 months. These TE-based BCNU or carboplatin three-drug combination HDC regimens are safe and tolerable with promising response rates in both children and older adults.

Phase I trial of sequential high-dose chemotherapy with escalating dose paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin with peripheral blood progenitor support in women with responding metastatic breast cancer

A single high-dose cycle of chemotherapy with stem cell support can produce disease-free survival of 15-20% for at least 3 years in women with responding stage IV breast cancer. North American Autologous Bone Marrow Transplant Registry data suggest that a complete response (CR) is the single most important prognostic factor associated with prolonged disease-free survival. Therefore, if sequential high-dose chemotherapy can increase the CR rate, then perhaps an increased proportion of patients will remain disease free. Women with at least a partial response (PR) to induction chemotherapy received three separate high-dose cycles of chemotherapy with peripheral blood progenitor support and granulocyte colony-stimulating factor. The first intensification was a dose escalation of paclitaxel (400-825 mg/ m2), the second intensification was melphalan (180 mg/m2), and the third intensification consisted of 6000 mg/m2 cyclophosphamide (1500 mg/m2/day), 500 mg/m2 thiotepa (125 mg/m2/day), and 800 mg/m2 carboplatin (200 mg/m2/day; CTCb). Thirty-six women were enrolled and 31 completed all three cycles. After the paclitaxel infusion most patients developed reversible predominantly sensory neuropathy. Of the 19 patients with measurable disease, 6 converted to CR, 7 converted to a PR* (the complete resolution of all soft tissue or visceral disease with sclerosis of prior lytic bone lesions), and 2 had a further PR for an overall response rate of 79%. Two patients had no further response and disease in two patients progressed, and thus they were taken off the study before CTCb. Seventy-eight percent are progression-free at a median follow-up of 14 months (range, 3-24+). Three sequential cycles of high-dose chemotherapy are feasible and were administered in this study with no mortality. Single agent paclitaxel at doses up to 825 mg/m2 were well tolerated with moderate reversible toxicity.

Systemic adjuvant therapy of breast cancer

Systematic adjuvant therapy has improved the outcome for women with operable breast cancer. As a result, a substantial proportion of patients with this disease are candidates for adjuvant treatment. In providing a woman with recommendations for therapy, her risk of developing recurrent breast cancer needs to be assessed in relationship to the degree of benefit she will obtain from treatment. With the range of presently available treatments, an individualized approach is necessary to provide the patient with options appropriate for her own situation. For women with a high risk of recurrence despite current standard adjuvant therapies, innovative approaches with high dose chemotherapy followed by infusion of autologous hematopoietic stem cells and growth factors are being evaluated. Ongoing clinical trials will demonstrate whether or not these newer therapies result in a better outcome.

Harvest quality and factors affecting collection and engraftment of CD34+ cells in patients with breast cancer scheduled for high-dose chemotherapy and peripheral blood progenitor cell support

The use of CFU-GM and CD34+ cell enumeration for assessing harvest quality and factors affecting peripheral blood progenitor cell (PBPC) harvest and engraftment were investigated in 45 women with high-risk and metastatic breast cancer scheduled for dose-intensive cyclophosphamide, thiotepa, and carboplatin (CTCb). PBPC were mobilized with standard breast cancer regimens or cyclophosphamide (1.5 g/m2) and 5 micrograms/kg/day G-CSF and used together with G-CSF for hematopoietic support post-CTCb. There was a significant correlation between peripheral blood CD34+ cells/microliter and harvest CD34+/kg (r = 0.73, p < 0.0001) and between harvest CFU-GM and CD34+ cells/kg (r = 0.5, p < 0.0001). CFU-GM clonogenic assays were of no clinical use beyond that of CD34+ cell enumeration, with the latter allowing for real-time decisions regarding harvesting. Multiple stepwise regression identified the number of prior chemotherapy cycles as the only significant clinical predictor of CD34+ cell yield. For 34 patients proceeding to CTCb with PBPC support, multiple stepwise regression identified as the best predictors for engraftment CFU-GM and CD34+ cells/kg for neutrophils and CFU-GM, CD34+ cells/kg, and the number of prior cycles of chemotherapy for platelets, respectively. A threshold dose of 1 x 10(6) CD34+ cells/kg, obtained in 87% of these heavily pretreated breast cancer patients, was adequate to ensure engraftment within 15 days. There was no significant difference in length of hospital stay or blood product use between patients receiving 1-2.5 x 10(6) CD34+ cells/kg and greater than 2.5 x 10(6) CD34+ cells/kg, although median time to engraftment of neutrophils (9 days versus 8 days, p = 0.007) and platelets (12 days versus 9 days, p = 0.006) was significantly longer. The established threshold of > or = 1 x 10(6) CD34+ cells/kg will allow for more confident consideration of using aliquots of this threshold dose for hematopoietic support in sequential high-dose regimens inclusive of CTCb.