Abstract 4596
Background
Achieving a residual cancer burden (RCB) 0-1 portends an excellent prognosis for TNBC pts receiving neoadjuvant (NACT) anthracycline (AC) and taxane chemotherapy while pts with high residual disease (RCB II-III) have a 40-80% recurrence risk. The GeparTrio and Aberdeen trials demonstrated that pts with poor response by ultrasound (US) during NACT had pathologic complete response (pCR) rates of 2-5% even if NACT was changed based on US response. Immunotherapy is a promising strategy for chemo-insensitive TNBC; however, given toxicity and potential for long-term morbidity, pt selection is important.
Methods
Pts identified as having chemo-insensitive TNBC with AC using US or through previous participation in a separate trial, ARTEMIS, were eligible. To identify insensitive TNBC, ARTEMIS used an algorithm combining a CLIA-certified chemo-sensitivity mRNA gene signature with US response to AC X4. Eligible pts then received weekly nab-paclitaxel (100 mg/m2 IV for 12 weeks) and atezo (1200mg IV q 3 weeks). Atezo continued for 3 months after surgery. Using a 2-stage Gehan-type design, if > 1 pt had an RCB 0-I in the first 19, the protocol would continue to accrue a total of 37 pts to estimate an RCB-0/I rate for atezo + nab-paclitaxel in chemo-insensitive TNBC for future trials. We report the interim analysis of the first 19 pts.
Results
19 pts enrolled from 02/2016- 12/12/2017. One pt received 1 cycle, then withdrew consent. Median age was 54 (range 35-75). Presenting clinical stage was II in 7 pts and III in 12 pts. Final pathology status was: RCB 0=5; RCB I = 1; RCB II = 5 and RCB III=7. RCB 0-I= 6/19 (32%). Toxicity included 6 serious adverse events in 3 pts: fever, elevated creatinine and post-surgical pain. Most common toxicities included fatigue, neuropathy, pain, anemia, rash, elevated transaminases, hyperglycemia, nausea and dyspnea. Six pts required atezo to be held and/or discontinued.
Conclusions
The combination of nab-paclitaxel and atezo resulted in moderate toxicity but increased the expected RCB 0-I rates from 5% to 32% for TNBC patients with chemotherapy-insensitive disease. Given these promising results, this study will continue to full accrual.
Clinical trial identification
NCT02530489.
Legal entity responsible for the study
Jennifer Litton.
Funding
MD Anderson Moonshot Program, Genentech.
Editorial Acknowledgement
Disclosure
J.K. Litton: Advisory boards (without personal compensation): AstraZeneca and Pfizer; Research studies: GSK, EMD Serono, Genentech, Pfizer, AstraZeneca, Novartis; CME with uptodate, med learning group, PER Guidelines; NIH PDQ and NCCN guidelines. E.A. Mittendorf; Advisory board: Merck and Sellas; Principal investigator: Genentech sponsored trials. All other authors have declared no conflicts of interest.