Abstract CT272: Phase 2 study of dianhydrogalactitol (VAL-083) in patients with MGMT-unmethylated, bevacizumab-naïve glioblastoma in the recurrent or adjuvant setting

Abstract

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care for glioblastoma (GBM) includes surgery followed by concurrent therapy with radiation and temozolomide (TMZ) followed by adjuvant TMZ (days 1-5 every 28 days). Almost all GBM patients experience recurrent/progressive disease, with a median survival of 3-9 months after recurrence. Second-line treatment for recurrent GBM with bevacizumab (BEV) has not improved survival, and effective therapies for GBM are lacking. Unmethylated promoter status for O6-methylguanine DNA methyltransferase (MGMT) is a validated biomarker for TMZ-resistance and is correlated with poor prognosis. VAL-083 is a bi-functional DNA-targeting agent rapidly inducing interstrand cross-links at N7-guanine, leading to DNA double-strand breaks and cell death. VAL-083's cytotoxicity is independent of MGMT status, and VAL-083 overcomes TMZ-resistance in GBM cell lines, GBM cancer stem cells, and in vivo GBM models. The trial described here is an open-label two-arm biomarker-driven phase 2 clinical trial in MGMT-unmethylated GBM patients with either recurrent disease (Group 1) or newly diagnosed GBM patients requiring adjuvant therapy after chemoirradiation with temozolomide (Group 2). Patients receive VAL-083 IV at 30 or 40 mg/m2/day on days 1, 2, and 3 of a 21-day cycle. The primary objective of this study is to determine the effect of VAL-083 on median overall survival (mOS) in MGMT-unmethylated recurrent GBM patients (Group 1) compared to historical control, and progression-free survival (PFS) in newly diagnosed GBM patients requiring adjuvant therapy after chemoirradiation with temozolomide (Group 2), compared to historical control. Secondary efficacy endpoints include progression-free survival (PFS) (Group 1), overall response rate (ORR), duration of response (DOR), and quality-of-life (QoL). Tumor response will be assessed by MRI approximately every 42 days, as per RANO criteria. The initial starting dose in this study was 40 mg/m2/day, which was subsequently reduced to 30 mg/m2/day to improve tolerance due to myelosuppression. As of 21st January 2020, thirty-five (35) subjects had enrolled at a starting dose of 40 mg/m2/day, and 31 subjects had enrolled at a starting dose of 30 mg/m2/day in Group 1, and 9 subjects enrolled at a starting dose of 30 mg/m2/day in Group 2. As anticipated from prior studies with VAL-083, myelosuppression (thrombocytopenia and neutropenia) has been the most common adverse event observed. Enrollment and safety data update will be provided at the meeting. Clinicaltrials.gov identifier: NCT02717962 Citation Format: Barbara J. O'Brien, Carlos Kamiya-Matsuoka, Shiao-Pei Weathers, Alfred Yung, Monica Loghin, Rebecca Harrison, Nazanin Majd, Jeffrey A. Bacha, Dennis M. Brown, Anne Steino, Gregory Johnson, Sarath Kanekal, John Langlands, Lorena M. Lopez, Richard M. Schwartz, Marta Penas-Prado, John F. de Groot. Phase 2 study of dianhydrogalactitol (VAL-083) in patients with MGMT-unmethylated, bevacizumab-naïve glioblastoma in the recurrent or adjuvant setting [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT272.