Ctni-50. update report of the respect-gbm phase i/iia dose escalation trial of rhenium-186 nanoliposome (186rnl) in recurrent glioma [rgbm] via convection enhanced delivery (ced)

Abstract BACKGROUND A Phase1/2a dose-escalation trial was initiated to determine the safety and recommended phase2 186RNL-dose(RP2D). Liposomal-rhenium-186(186RNL) is a source of high-energy beta-particles with gamma-photons representing attractive brain CED properties. METHODS A 3 + 3 Phase1 design was implemented per protocol [modified-Fibonacci dosing sequence]. We report safety and overall survival (OS) in 27 patients assigned to cohorts1-8. Patients with biopsy proven recurrent glioma had computerized treatment planning and placement of up to 5 intracranial catheter(s) single CED-186RNL administration. Whole body planar and SPECT/CT imaging through ~1 week following treatment was performed. Patients were followed for safety, sufficiency of delivery and OS. The significance of variation in OS was assessed with a 2-sided logrank test with α = 0.05. RESULTS Cohorts dosing ranged from 1mCi-in-0.6mL to 41.5mCi-in-16.3ml, MTD not reached, and no CED failures. No dose limiting toxicities were observed. Most common AEs were pre-existing GBM related signs/symptoms [weakness, fatigue, headache, seizure, scalp discomfort after CED] and >80% of AEs unrelated/unlikely relationship. Median absorbed radiation dose to the tumor (MARDT) was 308.4 Gy (8.9 Gy to 739.5 Gy). Patients were stratified by MARDT (< 100 Gy, ≥100 Gy). In all patients (N = 27), the median overall survival (OS) was 8 months (m), 95% CI 5 m to 13 m). In those receiving <100 Gy (N = 10), the median OS was 5 m (95% CI 1 m to 11 m) and in those with ≥ 100 Gy (N = 17) the median was 12 m (95% CI 5 m to 30 m), p < 0.001. CONCLUSION A single administration of 186RNL by CED in recurrent glioma patients is feasible, safe, and potentially effective in increasing overall survival when >100Gy radiation is delivered to the tumor. A RP2D of 22.3mCi in 8.8mL was selected for patients with tumor size of ≤20mL in the planned Phase 2B.