IMCT-03: SAFETY AND ACTIVITY OF NIVOLUMAB MONOTHERAPY AND NIVOLUMAB IN COMBINATION WITH IPILIMUMAB IN RECURRENT GLIOBLASTOMA: UPDATED RESULTS FROM CHECKMATE-143

INTRODUCTION: Following progression after first-line therapies, patients with glioblastoma (GBM) have a poor prognosis. Immune checkpoint inhibitors have shown antitumor activity in patients with several types of solid tumors and also in preclinical glioma models. The Phase 1 portion of CHECKMATE-143 was designed to evaluate the safety and tolerability of nivolumab, a fully human IgG4 monoclonal antibody targeting the programmed death-1 (PD-1) immune checkpoint pathway, as monotherapy and in combination with ipilimumab, a monoclonal antibody that inhibits CTLA-4, in patients with a first recurrence of GBM. All patients in Cohort 1 had prior surgical resection, radiation, and temozolomide. Median age was 57 years (range: 37–73), and KPS ≥70. Preliminary results from the study were previously presented and showed nivolumab monotherapy 3 mg/kg was well tolerated in patients with recurrent GBM, with no reported treatment-related grade 3–4 adverse events (AEs). Nivolumab 1 mg/kg in combination with ipilimumab 3 mg/kg was associated with a higher incidence of treatment-related grade 3 (n = 7/10) and grade 4 AEs (n = 2/10). Histopathologic and neuroimaging detected antitumor activity within the tumor site, and the preliminary overall survival (OS) rate at 9 months was 6/10 for both the monotherapy and combination arms. METHODS: Patients (n = 20) were randomized 1:1 to receive either nivolumab 3 mg/kg Q2W or nivolumab 1 mg/kg + ipilimumab 3 mg/kg Q3W followed by nivolumab 3 mg/kg Q2W. Eligible patients had no prior bevacizumab treatment and Karnofsky Performance Status ≥70. The primary endpoint was safety/tolerability. RESULTS: This report will provide updated follow-up data including safety and OS at 12 months.