INNV-16. COMPARISON OF SURVIVAL OUTCOMES OF RECURRENT GLIOBLASTOMA PATIENTS: A COMPARISON BETWEEN PATIENTS ENROLLED INTO CLINICAL TRIALS AND PATIENTS THAT DID NOT ENROLL INTO TRIALS AT FIRST PROGRESSION

Abstract

Abstract BACKGROUND Clinical trials in neuro-oncology use stringent eligibility criteria to select patients. We examined potential differences of survival outcomes in recurrent glioblastoma patients participating in clinical trials compared to trial-eligible patients treated outside of a trial. METHODS We reviewed 378 adult IDH-wild-type glioblastoma patients treated for first recurrence at our institution 2014-2020. We retrospectively evaluated patients for clinical trial eligibility based upon review of performance status, laboratory values (e.g. comprehensive metabolic panel, complete blood count), and other common eligibility criteria. Overall survival was defined as time from date of first recurrence to death. Cox proportional hazards modeling were used to evaluate outcomes of trial eligible patients compared to patients who received treatment on a clinical trial. RESULTS Among 378 patients, 171 patients (47%) enrolled onto a trial at first recurrence. Amongst 207 non-trial patients, 65 patients were excluded due to ineligibility or missing data. The primary reasons for trial ineligibility was known additional malignancy, thrombocytopenia, KPS < 60, active autoimmune disease, and presence of diffuse leptomeningeal disease. There were 142 (69%) patients deemed trial-eligible per our retrospective screening. In trial-eligible non-trial and trial participants (N=313), trial participation was associated with improved survival (Adjusted-HR 0.58, 95%CI 0.43-0.77, p< 0.001) after adjustment for age (HR 1.02, 95%CI:1.01-1.03, p=0.01), MGMT promoter methylation (HR 0.64, 95%CI:0.47-0.88, p=0.008), KPS at first recurrence (HR 0.99, 95%CI:0.97-1.00, p=0.02), time to first recurrence (HR 1.00, 95%CI:0.999-1.00, p=0.07), surgery at first recurrence (HR 0.96, 95%CI:0.72-1.27, p=0.77), standard 6 weeks radiation upfront (HR 0.47, 95%CI:0.25-0.87, p=0.02), and concurrent temozolomide use upfront (HR 0.71, 95%CI:0.43-1.15, p=0.18). CONCLUSION The most common reasons for clinical trial ineligibility in our cohort was additional malignancy, thrombocytopenia and poor performance status. In a single institution recurrent glioblastoma cohort, trial participation was associated with improved survival after adjustment of clinical covariates in this cohort.