Randomized phase II trial comparing axitinib with the combination of axitinib and lomustine in patients with recurrent glioblastoma

Axitinib is a small molecule tyrosine kinase inhibitor with high affinity and specificity for the family of vascular endothelial growth factor receptors. It has previously demonstrated anti-tumor activity in a small cohort of patients with recurrent glioblastoma (rGB). We conducted a non-comparative randomized phase II clinical trial investigating axitinib monotherapy versus axitinib plus lomustine (LOM) in patients with rGB. Primary endpoint was 6 month progression-free survival (6mPFS). Patients who progressed on axitinib-monotherapy were allowed to cross-over. Between August 2011 and July 2015, 79 patients were randomized and initiated axitinib monotherapy (n = 50; AXI) or axitinib plus lomustine (n = 29; AXILOM). Median age was 55y [range 18-80], 50M/28F. Baseline characteristics were well balanced between study arms. Nineteen patients in the AXI-arm crossed-over at the time of progression. Treatment was generally well tolerated. AXILOM patients were at higher risk for grade 3/4 neutropenia (0 vs. 21%) and thrombocytopenia (4 vs. 29%). Best Overall Response Rate (BORR) in the AXI-arm was 28 vs. 38% in the AXILOM-arm. 6mPFS was 26% (95% CI 14-38) versus 17% (95% CI 2-32) for patients treated in the AXI versus AXILOM-arms, respectively. Median overall survival was 29 weeks (95% CI 20-38) in the AXI-arm and 27.4 weeks (95% CI 18.4-36.5) in the AXILOM-arm. MGMT-promoter hypermethylation and steroid treatment at baseline correlated significantly with PFS and OS. We conclude from these results that axitinib improves response rate and progression-free survival in patients with rGB compared to historical controls. There is no indication that upfront combination of axitinib with LOM improves results (European Clinical Trials Database (EudraCT) Study Number: 2011-000900-16).