Safety and Feasibility of JAK Inhibitor Ruxolitinib in Newly-Diagnosed High-Grade Gliomas (CRUX): Final Trial Report

INTRODUCTION: Dysregulation of the JAK/STAT pathway in newly-diagnosed high-grade gliomas (nHGG) is linked to enhanced survival and proliferation of tumor cells. Ruxolitinib, a small molecule inhibitor of JAK1, JAK2, and JAK3, limits glioma growth in preclinical models. METHODS: This non-randomized prospective study included 60 WHO Grade 3-4 nHGG patients who received standard of care (SOC) therapy along with ruxolitinib in a 3 + 3 dose-escalation design; level 1 of 10 mg BID, level 2 of 15 mg BID, level 3 of 20 mg BID, level -1 of 5 mg BID. Primary study objective was determination of maximum tolerated dose (MTD) of ruxolitinib in combination with chemoradiation. Secondary objective was the determination of safety as assessed using NIH CTCAE scale, overall survival (OS), and progression-free survival (PFS). Exploratory aims were to investigate relationships between clinical outcomes and genomic signatures. RESULTS: 60 patients were enrolled, with median age 60.5 years (range 22-78), 23 (38%) female, and 37 (62%) were male. Amongst 59 evaluable patients, 29 (49%) were MGMT unmethylated and received ruxolitinib with 60Gy radiation over 6 weeks, while 30 (51%) patients were MGMT methylated and received ruxolitinib with 75mg/m2 of temozolomide (TMZ) with 60Gy radiation over 6 weeks. MTD for both cohorts was 20 mg BID. No dose-limiting toxicities were observed. Toxicities attributable to study medications included four grade 4 AEs including seizure, respiratory distress, somnolence, and thromboembolic event along with 14 grade 3 adverse events (AEs), including respiratory distress, seizure, gait disturbance, weakness, thrombocytopenia, cognitive disturbance, urinary retention, and meningitis. Median follow-up of patients alive was 34.2 months (range 18-52.2) with outcomes. CONCLUSIONS: Ruxolitinib therapy is safe and therapeutically feasible in combination with TMZ and radiation. A randomized phase 2 trial is planned.