Jeremy Lewin1, Jean-Charles Soria1, Anastasios Stathis1, Jean-Pierre Delord1, Solange Peters1, Ahmad Awada1, Philippe G Aftimos1, Mohamed Bekradda1, Keyvan Rezai1, Zhen Zeng1, Azher Hussain1, Susan Perez1, Lillian L Siu1, Christophe Massard1. 1. Jeremy Lewin and Lillian L. Siu, Princess Margaret Cancer Center, Toronto, Ontario, Canada; Jean-Charles Soria and Christophe Massard, Institut Gustave Roussy and University Paris-Sud, Villejuif; Jean-Pierre Delord, Institut Claudius Regaud Oncopole, Toulouse; Mohamed Bekradda, Oncology Therapeutic Development, Clichy; Keyvan Rezai, Hôpital René Huguenin, Saint-Cloud, France; Anastasios Stathis, Oncology Institute of Southern Switzerland, Bellinzona; Solange Peters, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland; Ahmad Awada and Philippe G. Aftimos, Université Libre de Bruxelles, Brussels, Belgium; and Zhen Zeng, Azher Hussain, and Susan Perez, Merck & Co, Kenilworth, NJ.
Abstract
PURPOSE: Birabresib (MK-8628/OTX015) is a first-in-class bromodomain inhibitor with activity in select hematologic tumors. Safety, efficacy, and pharmacokinetics of birabresib were evaluated in patients with castrate-resistant prostate cancer, nuclear protein in testis midline carcinoma (NMC), and non-small-cell lung cancer in this phase Ib study. PATIENTS AND METHODS: Forty-seven patients were enrolled to receive birabresib once daily at starting doses of 80 mg continuously (cohort A) or 100 mg for 7 consecutive days (cohort B) in 21-day cycles using a parallel dose escalation 3 + 3 design. The primary objective was occurrence of dose-limiting toxicities (DLTs) and determination of the recommended phase II dose. RESULTS: Of 46 treated patients, 26 had castrate-resistant prostate cancer, 10 NMC, and 10 non-small-cell lung cancer. For cohort A, four of 19 (21%) evaluable patients had DLTs at 80 mg once daily (grade 3 thrombocytopenia [n = 3], ALT/hyperbilirubinemia [n = 1]) and two of three had DLTs at 100 mg once daily (grade 2 anorexia and nausea with treatment delay > 7 days [n = 1], grade 4 thrombocytopenia [n = 1]). No DLTs occurred in cohort B. Of 46 patients, 38 (83%) had treatment-related adverse events (diarrhea, 17 [37%]; nausea, 17 [37%]; anorexia, 14 [30%]; vomiting, 12 [26%]; thrombocytopenia 10 [22%]). Three patients with NMC (80 mg once daily) had a partial response (Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) with duration of 1.4 to 8.4 months. Pharmacokinetic analysis indicated a dose-proportional increase in birabresib exposure and rapid absorption. CONCLUSION: The recommended phase II dose of birabresib in patients with select solid tumors is 80 mg once daily with continuous dosing. Birabresib has dose-proportional exposure and a favorable safety profile, with clinical activity observed in NMC. Future studies of birabresib must consider intermittent scheduling to possibly mitigate the toxicities of chronic dosing.
PURPOSE:Birabresib (MK-8628/OTX015) is a first-in-class bromodomain inhibitor with activity in select hematologic tumors. Safety, efficacy, and pharmacokinetics of birabresib were evaluated in patients with castrate-resistant prostate cancer, nuclear protein in testis midline carcinoma (NMC), and non-small-cell lung cancer in this phase Ib study. PATIENTS AND METHODS: Forty-seven patients were enrolled to receive birabresib once daily at starting doses of 80 mg continuously (cohort A) or 100 mg for 7 consecutive days (cohort B) in 21-day cycles using a parallel dose escalation 3 + 3 design. The primary objective was occurrence of dose-limiting toxicities (DLTs) and determination of the recommended phase II dose. RESULTS: Of 46 treated patients, 26 had castrate-resistant prostate cancer, 10 NMC, and 10 non-small-cell lung cancer. For cohort A, four of 19 (21%) evaluable patients had DLTs at 80 mg once daily (grade 3 thrombocytopenia [n = 3], ALT/hyperbilirubinemia [n = 1]) and two of three had DLTs at 100 mg once daily (grade 2 anorexia and nausea with treatment delay > 7 days [n = 1], grade 4 thrombocytopenia [n = 1]). No DLTs occurred in cohort B. Of 46 patients, 38 (83%) had treatment-related adverse events (diarrhea, 17 [37%]; nausea, 17 [37%]; anorexia, 14 [30%]; vomiting, 12 [26%]; thrombocytopenia 10 [22%]). Three patients with NMC (80 mg once daily) had a partial response (Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) with duration of 1.4 to 8.4 months. Pharmacokinetic analysis indicated a dose-proportional increase in birabresib exposure and rapid absorption. CONCLUSION: The recommended phase II dose of birabresib in patients with select solid tumors is 80 mg once daily with continuous dosing. Birabresib has dose-proportional exposure and a favorable safety profile, with clinical activity observed in NMC. Future studies of birabresib must consider intermittent scheduling to possibly mitigate the toxicities of chronic dosing.
Authors: Huiying Wang; Vivian L Weiss; Robert D Hoffman; Ty Abel; Richard H Ho; Scott C Borinstein; Kyle Mannion; Julia A Bridge; Jennifer Black; Jiancong Liang Journal: Head Neck Pathol Date: 2020-02-19