CTNI-49. PRECISION MEDICINE CLINICAL TRIAL FOR ADULT PATIENTS WITH RECURRENT GLIOBLASTOMA

Abstract Salvage therapies for recurrent glioblastoma (rGBM) have limited efficacy, with median overall survival of 9 months (OS-9) and 6-month progression-free survival (PFS-6) of 10-25%. Given GBM’s molecular heterogeneity, targeting a single molecular abnormality in isolation has consistently failed as a strategy, and precision combination approaches are needed. An initial 15-patient cohort evaluated the feasibility and safety of treating patients with rGBM with an individualized treatment regimen; we added a second 15-patient expansion cohort to improve the power of preliminary efficacy assessment. Patients underwent clinically indicated surgery with genomic profiling using the UCSF500 targeted DNA sequencing panel. Each personalized treatment regimen combined up to 4 FDA-approved drugs, including one cytotoxic agent, as determined by consensus discussion at an individualized molecular tumor board for each patient. Bevacizumab was not utilized in these combinations. The primary objective of the combined 30-patient cohort was efficacy of individualized treatment regimens by OS-9; secondary objectives included safety and additional efficacy measures including PFS-6. Median age was 53 years (range 32-71). Of 30 patients, 18 were male, 23 were enrolled at first recurrence, 29 had IDH-wildtype glioblastoma, 1 had IDH-mutant astrocytoma, and 10 had MGMT promoter methylation. A total of 12 FDA-approved drugs were used in 18 combinations; the most common regimen prescribed was lomustine, afatinib, and abemaciclib (7; 23%,); second-most common was temozolomide, olaparib, and afatinib (4; 13%). OS-9 of the combined cohort was 70% (95% CI 0.55 – 0.89) and PFS-6 was 27% (95% CI 0.15 – 0.48), with median OS of 11.6 months (95% CI 9.7 – 16.7) and median PFS of 3.7 months (95% CI 2.0 – 5.5).While overall efficacy was modest, implementation of individualized treatment regimens in a timely fashion was safe and feasible for patients with surgically resectable rGBM. Analysis is ongoing to assess whether specific genomic profiles or treatment regimens were particularly efficacious.