Clinical characterization of patients with recurrent glioblastoma in trials involving CED and non-CED treatment.

Abstract

e18845 Background: Glioblastoma (GBM) is the most common and aggressive of the primary malignant brain tumors in adults. Bevacizumab (beva) remains the only currently approved therapeutic for recurrent GBM (rGBM) patients who progress on prior therapy. Despite advances in care, rGBM has a median expected progression-free survival (PFS) of < 4 months and overall survival (OS) of ~8 months. NCCN guidelines [Version 2.2022], and other oncology medical societies unanimously recommend patients seek treatment by entering a clinical trial. Since the late 1990’s a number of studies have explored the use of convection-enhanced delivery (CED) of drugs, a well-accepted and widely published delivery option for the treatment of rGBM. This analysis compares the demographics, medical history and survival outcome of patients enrolled into recently completed clinical trials with beva monotherapy to those entered into CED studies. Methods: Data for this analysis was sourced from the Medidata Enterprise Data Store (MEDS), comprised of over 28,000 historical clinical trials for de-identified aggregate patient-level analyses and from the study and patient-level data in the CED studies referenced in D’Amico [J Neurooncol 2021]. Aggregate summary statistics comparing beva and CED patients were based on combined study- and patient-level data using weighted (by sample size) means, incidence and overall survival (OS) rates and median of medians. Results: 163 rGBM beva patients were identified from MEDS. The CED cohort included 636 patients from MEDS and studies referenced in D’Amico. Cohort comparisons (beva vs CED) found median age: 56 vs 55 years; Caucasian race: 91% vs 93%; male sex: 68% vs 65%; not Hispanic or Latino ethnicity: 90% vs 94%; median OS: 7.9 vs 8.4 months. Over the last 2 decades there was a 23% increase in patients with ECOG Performance Status = 0 and 25% decrease in tumor area size at study enrollment, whereas there was no clear temporal OS trend. Conclusions: Patient demographics and most tumor attribute variables were similarly distributed between the beva and CED cohorts. While there is some indication that recent CED studies have enrolled healthier patients with smaller tumors; as expected, this does not appear to have translated to a consistent survival benefit.