Safety, Tolerability, and Pharmacokinetics of TAK-931, a Cell Division Cycle 7 Inhibitor, in Patients with Advanced Solid Tumors: A Phase I First-in-Human Study

Purpose: We conducted a first-in-human, dose-escalation study, to eval-uate the safety, tolerability, pharmacokinetics, pharmacodynamics, and activity of TAK-931, a cell division cycle 7 inhibitor, in Japanese patients with advanced solid tumors. Experimental Design: Patients ages & GE;20 years received oral TAK-931: once daily for 14 days in 21-day cycles (schedule A; from 30 mg); once daily or twice daily for 7 days on, 7 days off in 28-day cycles (schedule B; from 60 mg); continuous once daily (schedule D; from 20 mg); or once daily for 2 days on, 5 days off (schedule E; from 100 mg) in 21-day cycles.Results: Of the 80 patients enrolled, all had prior systemic treatment and 86% had stage IV disease. In schedule A, 2 patients experienced dose-limiting toxicities (DLTs) of grade 4 neutropenia and the maximum tolerated dose (MTD) was 50 mg. In schedule B, 4 patients experienced DLTs of grade 3 febrile neutropenia (n = 3) or grade 4 neutropenia (n = 1); the MTD was 100 mg. Schedules D and E were discontinued be-fore MTD determination. The most common adverse events were nausea (60%) and neutropenia (56%). Time to maximum plasma concentration of TAK-931 was approximately 1-4 hours postdose; systemic exposure was approximately dose proportional. Posttreatment pharmacodynamic effects correlating to drug exposure were observed. Overall, 5 patients achieved a partial response.Conclusions: TAK-931 was tolerable with a manageable safety profile. TAK-931 50 mg once daily days 1-14 in 21-day cycles was selected as a recommended phase II dose and achieved proof of mechanism. Trial registration ID: NCT02699749Significance: This was the first-in-human study of the CDC7 inhibitor, TAK-931, in patients with solid tumors. TAK-931 was generally tolerable with a manageable safety profile. The recommend phase II dose was deter-mined to be TAK-931 50 mg administered once daily on days 1-14 of each 21-day cycle. A phase II study is ongoing to confirm the safety, tolerability, and antitumor activity of TAK-931 in patients with metastatic solid tumors.