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TBCRC009: A multicenter phase II study of cisplatin or carboplatin for metastatic triple-negative breast cancer and evaluation of p63/p73 as a biomarker of response.
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Triple-negative breast cancer (TNBC) has a poor prognosis compared to other BC subtypes and lacks specific therapeutic targets. Platinum chemotherapy (CTx) may be active in this population. The p53 family members p63 and p73 are expressed in about 40% of TNBC and may predict response to platinum. TBCRC009 is a multicenter single arm phase II study of single agent platinum in metastatic TNBC. Methods: Eligible metastatic TNBC patients (pts) had measurable disease, available archival tumor, ≤ 1 prior metastatic therapy, and no prior platinum CTx. Pts were assigned by physician choice (limited to equal enrollment in each arm) to cisplatin 75mg/m2 or carboplatin AUC=6 every 21 days with optional extension to 28 days after cycle 1. Co-primary endpoints were: 1) Response Rate (RR) and 2) whether tumor p63/p73 expression by qRT-PCR predicts response. Results for endpoint 1 are presented. Results: 86 TNBC pts enrolled between June 2007-Oct 2010. Med age=52 (30-78), 80% White, 8% Black. 64% had ECOG PS=0, 86% had adjuvant CTx, 70% had prior anthracycline and 73% prior taxane. Mean # of disease sites = 2.4; lymph nodes (52), lung (41), bone (25), liver (24). Optional research biopsies were collected from 8 pts. Overall RR was 30.2% (95% CI 22.1%-39.4%), including 4 CR (4.7%), 22 PR (25.6%). All 4 CRs remain progression-free 156, 71, 44, and 24 weeks since study entry, and 3 stopped treatment after 6 cycles. The CBR (CR+PR+SD>6 mo) was 34%. Exploratory subgroup analysis of RR: Cis 37%, Carbo 23%; 1st line 31.7%, 2nd line 20%. Med # cycles = 4 (range 1-19), with 10 pts ≥ 10 cycles. Med PFS = 89 days and 4 pts remain on study at abstract submission. 33% of pts progressed by 6 weeks, but 33% remained on study for ≥ 6 mos. 51 treatment related grade 3/4 toxicities occurred: Gr 4 included neutropenia (1) and HTN (1); Gr3 included fatigue (8), neutropenia (6), anemia (5), hyponatremia (4). Conclusions: First or second line single agent platinum is active and well tolerated in metastatic TNBC with durable CRs and PRs. p63/p73 analysis, additional correlative studies, and BRCA mutation analysis is ongoing. Final updated efficacy analysis for primary endpoint 1 will be presented.
Abstracts by S. J. Isakoff:
Functional metabolic tomographic optical breast imaging (TOBI) to monitor response to neoadjuvant therapy in breast cancer.Meeting: 2011 Breast Cancer Symposium | Abstract No: 60
ACRIN 6691 monitoring and predicting breast cancer neoadjuvant chemotherapy response using diffuse optical spectroscopic imaging (DOSI).Meeting: 2011 ASCO Annual Meeting | Abstract No: TPS249Category: Tumor Biology - Prognostic Factors
Functional metabolic tomographic optical breast imaging (TOBI) to monitor response to neoadjuvant therapy in breast cancer.Meeting: 2011 ASCO Annual Meeting | Abstract No: 10607Category: Tumor Biology - Prognostic Factors