A multicenter, 3-arm, open-label, phase IIa clinical trial to evaluate the safety and efficacy of tanibirumab (VEGFR2 mAb), in patients with recurrent glioblastoma (GBM).

Abstract

e13522 Background: Treatment of recurrent GBM remains a challenge. The VEGF signal transduction pathway is upregulated in GBM. We evaluated Tanibirumab, a mAb to VEGFR2, in an open-label, dose-escalation, 3-arm, Phase 2a clinical trial. Primary and secondary endpoints were determining safety and efficacy (6-month PFS, ORR, DCR and OS). Methods: Eligibility criteria included age ≥19 yrs at 1st or 2nd recurrence of GBM, measurable disease, KPS≥80, and no prior bevacizumab. Patients were enrolled in 3 arms: Arm 1 (8mg/kg d1,8,15/q28 days); Arm 2 (12mg/kg d1,8,15/q28 days) and Arm 3 (12mg/kg weekly). Response evaluation with MRI (RANO criteria) including DCE, was performed every 2 cycles. Results: 12 patients were enrolled over 10 months from 2 sites: 3 patients each in Arms 1 & 2; 6 in Arm 3. The median age was 50 years and 8 were male. 6 patients had second recurrence. At 1st infusion, 8 out of 12 were on baseline corticosteroids. 10 patients have progressed. No dose limiting toxicities (DLT) were observed. Cutaneous hemangiomas (CH) were frequent (83% of patients) and all G2 or less. No drug-related G3 or 4 AEs were observed. All SAEs were unrelated to the study drug apart from G2 bleeding haemangioma and G2 cerebral haemorrhage. Expected AEs with anti-angiogenic drugs (hypertension; impaired wound healing) were not observed. Among 12 patients allocated to Arm 1, 2 and 3, no objective radiological responses were observed. 3 patients demonstrated stable disease (SD); 2 patients had SD beyond 4 cycles and are still receiving treatment at weeks 45 (Arm 1) & 20 (3). This was correlated with the highest expression of VEGFR2 using immunohistochemistry on archival tumour and blood vessels. Only 2 patients needed to initiate or increase corticosteroids for control of tumor edema while on treatment. Current data are immature to determine time to event efficacy endpoints (PFS,OS). Conclusions: Tanibirumab can be safely administered to patients with recurrent GBM, with CH being common. SD was seen in 2 patients up to 10+ months, with some indication that VEGFR2 expression may be a response biomarker. Clinical trial information: NCT03033524.