2017 ASCO Annual Meeting!
Session: Breast Cancer—Metastatic
Type: Poster Session
Time: Sunday June 4, 8:00 AM to 11:30 AM
Location: Hall A
Efficacy/safety of epacadostat plus pembrolizumab in triple-negative breast cancer and ovarian cancer: Phase I/II ECHO-202 study.
2017 ASCO Annual Meeting
Poster Board Number:
Poster Session (Board #95)
J Clin Oncol 35, 2017 (suppl; abstr 1103)
Author(s): Alexander I. Spira, Omid Hamid, Todd Michael Bauer, Virginia F. Borges, Jeffrey S. Wasser, David C. Smith, Amy Sanders Clark, Emmett V. Schmidt, Yufan Zhao, Janet E. Maleski, Tara C. Gangadhar; Virginia Cancer Specialists Research Institute, Fairfax, VA; The Angeles Clinic and Research Institute, Los Angeles, CA; Sarah Cannon Research Institute and Tennessee Oncology, PLLC, Nashville, TN; University of Colorado Denver, Aurora, CO; University of Connecticut Health Center, Farmington, CT; University of Michigan, Ann Arbor, MI; Abramson Cancer Center, Philadelphia, PA; Merck & Co., Inc., Kenilworth, NJ; Incyte Corporation, Wilmington, DE
Background: Epacadostat is an oral, potent, and selective inhibitor of indoleamine 2,3-dioxygenase 1, a tryptophan-catabolizing enzyme that induces immune tolerance via T-cell suppression and is associated with poor patient (pt) survival when overexpressed in some cancers. The ongoing, open-label, phase 1/2 (P1/2) ECHO-202/KEYNOTE-037 study is evaluating the efficacy, safety, and tolerability of epacadostat plus PD-1 inhibitor pembrolizumab (E + P) in pts with advanced/recurrent cancers. We report P1/2 study outcomes for triple-negative breast cancer (TNBC) pts and P2 outcomes for ovarian cancer (OVC; no P1) pts as of a 29OCT2016 data cutoff. Methods: Eligible pts were ≥18 years old with no prior checkpoint inhibitor treatment (tx); prior platinum/taxane tx was required for OVC pts. As part of P1 dose escalation, TNBC pts received E (300 mg BID) + P (200 mg Q3W). In P2, TNBC and OVC pts received E (100 mg BID) + P (200 mg Q3W). Response (RECIST v1.1) was assessed in evaluable pts. Safety and tolerability were assessed in pts with ≥1 dose of E + P. Results: A total of 39 pts with TNBC and 37 with OVC were enrolled. The majority of TNBC pts (56%, n = 22) and OVC pts (78%, n = 29) received ≥3 prior lines of tx. For TNBC pts, ORR (CR+PR) was 10% (n = 4; all PR) and DCR (CR+PR+SD) was 36% (n = 14; 10 SD); ORR and DCR for pts with ≤2 prior tx were 12% (n = 2) and 29% (n = 5), respectively, and for ≥3 prior tx were 9% (n = 2) and 41% (n = 9). For OVC pts, ORR was 8% (n = 3; all PR) and DCR was 35% (n = 13; 10 SD); ORR and DCR for pts with ≤2 prior tx were 13% (n = 1) and 25% (n = 2), and for ≥3 prior tx were 7% (n = 2) and 38% (n = 11). The most common TRAEs (≥15% of pts) were rash (18%), fatigue (15%), and nausea (15%) in the 39 TNBC pts, and fatigue (19%) in the 37 OVC pts. Grade ≥3 TRAEs occurred in 13% of TNBC pts (n = 5; none in > 1 pt) and 19% of OVC pts (n = 7; only rash occurred in > 1 pt [n = 3]). TRAEs led to discontinuation in 1 TNBC pt (grade 3 ascites) and 1 OVC pt (grade 2 arthralgia). Conclusions: E + P tx was generally well tolerated and showed antitumor activity consistent with previously reported P monotherapy in pts with advanced TNBC or OVC. Biomarker analysis is ongoing to characterize pt populations enrolled in this study. Clinical trial information: NCT02178722