Nanda, Rita

Abstract Background: The potential for exploiting BRCA deficiencies with DNA repair inhibitors has both pre-clinical and clinical support. ABT-888 (veliparib), a DNA repair inhibitor initially thought to target Poly(ADP-Ribose) Polymerases (PARP), has demonstrated in vitro inhibition of BRCA1 and BRCA2 deficient mouse embryonic stell cells, with a larger effect on BRCA1 cells. We report on the pre-planned interim analysis of the efficacy of single agent veliparib in patients with either BRCA1 or BRCA2-associated stage IV breast cancer. Methods: BRCA 1 or 2 carrier patients with stage IV breast cancer, with measurable disease, without prior exposure to a PARP inhibitor or a platinum compound in the metastatic setting, were eligible. Velapirib was administered orally, at doses of 400 mg twice daily. Dose adjustments based on toxicity were permitted. Patients progressing on velapirib alone received carboplatin at an AUC of 5, IV, given Q 21 days, and velapirib 150 mg twice daily (the maximum tolerated dose [MTD] of the combination from our completed Phase I study: J Clin Oncol 30, 2012 [suppl; abstr 1024]). Patients were to be accrued from 7 NCI NO1- supported consortia. Initially 10 patients were to be accrued to each stratum (BRCA1 and BRCA2) to provide evidence of single agent activity. If there was sufficient activity to warrant consideration of velapirib as single agent therapy (defined as 2 or more confirmed partial [PR] or better responses out of 10 per stratum), an additional 12 patients would be accrued per stratum. Results: 20 evaluable patients (11 BRCA1 and 9 BRCA2 [1 in screening]) have been accrued, the majority with lung or liver as visceral metastatic sites of disease. Median age (range) is 46 (29-68) years. Tumors from 9 patients were hormone receptor positive. BRCA1 cohort: 4 of 11 patients are off treatment at a median of 2 months (1-4); 1 patient stopped velapirib due to toxicity (grade 2 rash/pruritus, grade 2 vomiting), 3 stopped for progressive disease (one with an unconfirmed PR). Seven patients are still on single agent veliparib with 1 unconfirmed PR, and 1 patient with two evaluations showing stable disease. BRCA2 cohort: 2 patients are off treatment at 2 months for progressive disease, 7 are still on treatment with 1 confirmed PR, and 3 unconfirmed PRs. Data on patients receiving combination of velapirib and carboplatin after progression is too early. Treatment-related toxicity is being updated and has so far been reported from 14 patients: 1 patient had grade 3 fatigue, 1 patient with liver metastasis had both grade 3 alanine aminotransferase elevation and grade 3 abdominal pain. Grade 2 toxicities occurring in more than 1 patient included nausea/vomiting (6 patients), chills (2 patients), and fatigue (2 patients). Conclusion: Velapirib has single agent activity in both BRCA1 and BRCA2-associated stage IV breast cancer patients, and is well-tolerated. Mature response, treatment, and toxicity data will be presented. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-05.

Abstract Background: Circulating Tumor cells (CTCs) are prognostic at baseline and first follow-up in patients with metastatic breast cancer (MBC). Using the most commonly used assay (CellSearch®), we have previously reported the ability to detect apoptotic vs. non-apoptotic CTCs in patients with MBC. However, there has been concern regarding the performance of the CellSearch® assay in patients with triple negative (TN) MBC. We hypothesized that CellSearch® is an effective assay in patients with TN MBC, and that CTC-apoptosis might further separate prognosis. Therefore, we studied CTCs in patients with TN MBC who participated in a prospective randomized phase II trial testing for activity of tigatuzumab (TIG) in combination with nanoparticle albumin-bound paclitaxel (nab-PAC) conducted by the Translational Breast Cancer Research Consortium (overall results reported by Forero A., et al, ASCO 2013). Methods: Whole blood (WB) was drawn into a CellSave tube at baseline, day 15, and day 29 and CTC counts were determined using the CXC CellSearch® kit. Apoptosis was characterized by staining with a monoclonal antibody that detects a neo-epitope on fragmented cytokeratin (M-30) and independently by visual inspection (nucleic condensation and/or fragmentation, as well as granular cytokeratin). Association between levels of CTCs and CTC-apoptosis with the overall response rate (ORR) and progression free survival (PFS) at baseline, day 15, and day 29 was assessed using logistic regression, Kaplan Meier curves, and Cox proportional hazards modeling. Results: Of the 60 patients entered into the trial, 52 were evaluable for CTCs. Of these, 19/52 (36.5%), 14/52 (26.9%), and 13/49 (26.5%) had elevated CTCs (≥5CTC/7.5 ml WB) at baseline, day 15, and day 29, respectively. Patients with elevated CTCs at each time point had worse PFS than patients with low or no CTCs. Hazard rates (HR) at baseline, day 15, and day 29 were 2.38 (95% CI: 1.27-4.45, p = 0.007), 2.87 (95% CI: 1.46-5.66, p = 0.002), and 3.40 (95% CI: 1.68-6.89, p = 0.001), respectively. The odds of overall response for those who had elevated CTCs compared to those who did not at baseline, day 15, and day 29, were 0.25 (95% CI: 0.073-0.81, p = 0.024), 0.18 (95% CI: 0.04-0.67, p = 0.014), and 0.06 (95% CI: 0.01-0.28, p = 0.001), respectively. There was no apparent prognostic effect comparing the degree of CTC-apoptosis vs. non-apoptosis. Conclusions: Similar to observations in other intrinsic subgroups, CTCs were detected in a large fraction of TN MBC patients at baseline using CellSearch® assay, and reductions in CTC levels reflected response. In these homogenously prospectively enrolled TN MBC patients, regardless of treatment, CTCs are prognostic at baseline, day 15, and day 29. It does not appear that analysis of CTC-apoptosis is prognostic. Supported by Susan G. Komen for the Cure, Veridex, LLC, Fashion Footwear Charitable Foundation of New York/QVC Presents Shoes on Sale™ (DFH), Associazione Sandro Pitigliani and by a studentship from FIRC (CP), Triple Negative Breast Cancer Foundation, The AVON Foundation, and The Breast Cancer Research Foundation. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-04-01.

Purpose We previously reported the eradication of human epidermal growth factor receptor 2 (HER2)– amplified human xenografts in mice by inhibition of the HER2 pathway with lapatinib and trastuzumab to block all homo- and heterodimer signaling as well as by blockade of estrogen receptor (ER) when expressed. In this clinical trial, we sought to translate these findings to patients using targeted therapy without chemotherapy. Patients and Methods Women with stages II to III HER2-positive breast cancers were eligible. They received trastuzumab once per week (4 mg/kg loading, then 2 mg/kg) and lapatinib 1000 mg once per day for 12 weeks. Women with ER-positive tumors also received letrozole (plus a luteinizing hormone–releasing hormone [LHRH] agonist if premenopausal). Pathologic response was assessed by ER status. Biopsies were obtained at baseline, weeks 2 and 8, and time of surgery. Results Sixty-six patients were enrolled, and 64 were eligible and evaluable for response. Median tumor size was 6 cm (range, 1.5 to 30 cm). Adverse events were mainly grades 1 to 2 (GI, 63%; skin, 46%). Grade 3 metabolic, GI, and liver (18%; 12 patients) and grade 4 liver toxicities (one patient) were also observed. Overall, in-breast pathologic complete response (pCR; yp T 0 - is ) was 27% (ER positive, 21%; ER negative, 36%). The rate of low-volume residual disease ( yp T 1a-b ) was 22% (ER positive, 33%; ER negative, 4%). Conclusion In patients with locally advanced HER2-positive breast cancer, our approach of targeted therapy only resulted in a high pCR rate without chemotherapy. Our data support the hypothesis that selected patients with HER2-positive tumors may not need chemotherapy, and more-complete blockade of HER receptors and ER is an effective strategy worthy of further study.

Abstract Background We evaluated the safety and efficacy of L+T in pts with 0–2 prior lines of chemotherapy (CT) for HER2+ MBC. In the context of this phase II trial, we evaluated metabolic response by FDG-PET and explored the relationship between metabolic response and clinical outcomes. Methods: Pts with measurable, HER2+ MBC were eligible. Cohort 1: No prior T, L, or CT +T for MBC, and >1 yr from adjuvant T, if received. Cohort 2: 1–2 prior lines of CT for MBC, including T, or relapse within 1 yr of adjuvant T. Pts received L 1,000 mg QD + T (2 mg/kg weekly or 6 mg/kg Q3W). Staging studies were done with CT or MRI at baseline (BL) and every 2 cycles (1 cycle=4 weeks [wks]). Objective response was assessed by local investigator according to RECIST 1.0. FDG-PET/CT was performed at BL, Wk 1, and Wk 8 per NCI guidelines. Central quality assurance, review, and analysis were performed on FDG-PET studies. Up to 5 target lesions were identified on BL FDG-PET images based on hypermetabolic uptake. Percent change in the summed maximum standardized uptake value (SUVmax) of target lesions was calculated at Wk 1 or Wk 8, compared to BL. Metabolic response was assessed according to EORTC criteria for % change in SUVmax (progressive disease [PD]: ≥25% increase; partial response [PR]: ≥25% decrease; stable disease [SD]: <25% change). Metabolic response at Wk 1 was compared to Wk 8 as well as to clinical outcome, including objective response, clinical benefit, and progression-free survival (PFS). Results: 87 pts were registered to the study. Of these, one pt did not begin protocol therapy and one pt did not have MBC on further testing, and are not included. 81/85 pts had FDG-PET data at Wk 1; 75/85 had data at Wk 8. Metabolic PR at Wk 1 was observed in 28/39 (72%) pts in Cohort 1 and 20/42 (48%) pts in Cohort 2. Metabolic PR at Wk 8 was observed in 27/34 (79%) pts in Cohort 1 and 18/41 (44%) pts in Cohort 2. Wk 1 and Wk 8 metabolic responses were similar. In cohort 1, 18/28 (64%) pts who achieved Wk 1 metabolic PR had clinical benefit by RECIST. Of pts with Wk 1 metabolic SD, 2/9 (22%) had clinical benefit. In cohort 2, 9/20 (45%) pts who achieved Wk 1 metabolic PR had clinical benefit; 5/22 (23%) who achieved Week 1 metabolic SD had clinical benefit. Exploratory analysis of progression-free survival (PFS) showed that pts in Cohort 1 who achieved Wk 1 metabolic PR experienced a median PFS of 9.3 months ([mos]; 95% CI 5.6−22.3); for pts with metabolic SD, median PFS was 1.9 mos (95% CI 0.8−5.5). For pts in Cohort 2, Wk 1 metabolic PR was associated with median PFS of 5.6 mos (95% CI 3.7−7.8), whereas for pts with metabolic SD, median PFS was 3.7 mos (95% CI 1.8−5.5). Conclusions: L+T is associated with a high rate of early and sustained metabolic response by FDG-PET. Exploratory analyses suggest that metabolic PR may be associated with clinical benefit and longer PFS. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-09-07.