Efficacy and safety of selinexor in recurrent glioblastoma.

Abstract

2005 Background: New treatment modalities are needed for recurrent glioblastoma (rGBM). Selinexor (SEL) is a novel, oral selective inhibitor of nuclear export which forces nuclear retention of tumor suppressor proteins including p53 and p27, leading to apoptosis. We previously reported interim results showing tolerability, preliminary efficacy, and blood-brain barrier penetration in a surgical cohort (N = 8). We now report updated results following completion of accrual to non-surgical cohorts (N = 68). Methods: This is an open-label, multicenter, phase 2 study of SEL monotherapy. Patients (pts) not undergoing surgery for measurable rGBM (per RANO) were enrolled in one of 3 arms encompassing different dosing schedules. Treatment was continuous, although cycles were defined as 28 days and response was assessed every other cycle by MRI. Prior treatment with radiotherapy and temozolomide was required and prior bevacizumab was exclusionary. The primary endpoint was 6-month progression free survival (6mPFS) rate, calculated by the Kaplan Meier method. Results: A total of 76 pts were enrolled. Median age was 56 years (range 21-78). Median number of prior treatments was 2 (range 1-7). At the end of the 6 cycles, 30.2% patients on 80 mg QW were free from progression. The 6mPFS rate on 80 mg QW was 15.1%. Best RANO-defined responses (assessed locally) among 26 evaluable pts on 80 mg QW included 1 complete response, 2 partial responses, 7 stable disease, and 16 with progressive disease. Median duration of response was 10.8 months. The most common related adverse events in pts on ~85 mg BIW/60 mg BIW/80 mg QW were nausea (42%/64%/60%), leukopenia (38%/7%/43%), fatigue (71%/71%/43%), neutropenia (29%/14%/33%), decreased appetite (46%/71%/27%), and thrombocytopenia (67%/29%/23%). Conclusions: SEL demonstrated efficacy, with durable responses and disease stabilization in rGBM. Based on the favorable efficacy and safety profile, SEL at a dose of 80 mg QW is recommended for further development in rGBM. Clinical trial information: NCT01986348. [Table: see text]