Second line treatment of recurrent glioblastoma with sunitinib: results of a phase II study and systematic review of literature.

Introduction: Second line treatment of recurrent or progressive glioblastoma multiforme (GBM) is not standardized. Anti-angiogenic strategies with tyrosine-kinase inhibitors have been tested with conflicting results. We tested the association of sunitinib plus irinotecan (CPT-11) in a phase II trial in terms of response rate (RR) and 6-months progression-free survival (6-PFS). We also reviewed the clinical evidence from all the trials with sunitinib in this setting published to date and summarized it in a meta-analysis.

Evidence Acquisition: Patients with GBM recurrent or progressive after surgery and standard chemo-radiotherapy were treated with sunitinib 37.5 mg/day for 14 days + CPT-11 125 mg/sqm every 14 days in a Simon's two-stage phase II study. A summary data meta-analysis was performed to establish the 6-PFS in patients with ascertained histological diagnosis of GBM treated with sunitinib.

Evidence Synthesis: Six patients were enrolled in the stage I of the trial and only one had a stable disease. The overall response rate was 17% and 6-PFS was not reached. Therefore, the trial was stopped early for insufficient activity. All toxicities were grade 1-2. Systematic review of the literature identified 9 studies (including the present one) for a total of 221 patients. Pooled 6-PFS was 15.1% (95% CI: 9.0-24.4). Subgroup analysis by different schedule revealed a 6-PFS of 17.5% (95% CI: 10.3-28.1) in the weekly setting which was consistent across all the studies (I2=0%, P=0.66) and a pooled 6-PFS of 12.7% (95% CI: 4.9-29.1) in the daily setting with a substantial amount of heterogeneity (I2=65%, P=0.01).

Conclusions: Results of this trial and those of the systematic review indicate that, compared to conventional chemotherapy or bevacizumab, sunitinib has insufficient activity in the setting of recurrent GBM. Better patient's molecular stratification for second-line treatment in GBM is warranted.