EPID-07. Treatment with gabapentin associated with improved survival in elderly glioblastoma patients

Abstract Glioblastoma’hijacks’ neuronal pathways to drive tumor growth, and drugs affecting the function of these pathways may potentiate survival gains. Prior studies suggest a clinical benefit with using gabapentin. In this analysis, we assess the impact of taking gabapentin after glioblastoma diagnosis utilizing an active comparator model in a population-based dataset of older adults in the United States. We leveraged Surveillance, Epidemiology and End Results data paired with Medicare claims to investigate gabapentin’s effect on overall survival in patients receiving resection, radiation, and temozolomide from 2008-2019 (followed through 2020). Patients were excluded if <66 years of age, not enrolled in Medicare Parts A/B/D for equal time, missing follow-up, or diagnosis by autopsy/death certificate. Duloxetine and levetiracetam were used as active comparators. Association between medication and overall survival was assessed using cox proportional hazards models adjusted for age at diagnosis, sex, race/ethnicity, Charlson comorbidity score, extent of resection. There were 2,490 individuals available for analysis. Of these, 797 (32%) received temozolomide alone (TMZ), 147 (5.9%) received gabapentin and temozolomide (TMZ+G), 38 (1.5%) received duloxetine and temozolomide (TMZ+D), and 1,514 (60.8%) received levetiracetam and temozolomide (TMZ+L). Median survival for TMZ was 10 months (95%CI=9.14-10.9), as compared to TMZ+G (16.3 months, 95%CI=13.19-19.2), TMZ+D (16 months, 95%CI=10.0-22.9), TMZ+L (13.0 months, 95%CI=12.29-13.8). In the adjusted model, use of TMZ+G was associated with a 47% decrease in hazard of death (HR=0.53, 95%CI=0.44-0.64, p<0.001), while TMZ+D had a 38% decrease (HR=0.62, 95%CI=0.43-0.89, p<0.001), and TMZ+L had a 23% decrease (HR=0.77, 95%CI=0.71-0.84, p<0.001) compared to TMZ. In TMZ+G, Women had a 55% decrease in hazard of death (HR=0.45, 95%CI=0.34-0.60, p<0.001) compared to 47% in men (HR=0.63, 95%CI=0.46-0.83) as compared to TMZ. These results show survival benefit associated with gabapentin use, and supports ongoing work suggesting that neuron-glioma interactions represent important therapeutic targets.