Clinical and radiographic prognostic factors in recurrent contrast-enhancing IDH-Mutant Gliomas treated with Bevacizumab

Abstract Background While bevacizumab, an anti-angiogenic monoclonal antibody, is approved for recurrent IDH wild-type glioblastoma, reports on clinical outcomes of IDH-mutant gliomas receiving this therapy are scarce. We retrospectively evaluated prognostic variables associated with outcomes in a cohort of recurrent contrast-enhancing IDH-mutant gliomas treated with bevacizumab. Methods Ninety-seven consecutive patients were retrospectively studied. Age, biological sex, Karnofsky performance status (KPS), number of prior recurrences, prior disease duration, 1p19q status, MGMT status, and therapy schemes were annotated as clinical variables. MRI datasets were used to quantify pre-bevacizumab contrast-enhancing tumor volume, immediate percent volumetric reduction after bevacizumab, and RANO radiographic response. Clinical and radiographic variables were evaluated as predictors of progression-free survival (PFS) and overall survival (OS) in multivariate Cox survival analyses. Results Median PFS and OS were 3.62 and 10.49 months, respectively. A lower number of recurrences prior to bevacizumab initiation (P = .002 OS; P = .004 PFS), 1p19q codeletion (P = .005 OS; P = .0007 PFS), a higher KPS (P = .02 OS; p=ns PFS), treatment schemes including immunotherapies (P = .03 OS; p=ns PFS), a smaller baseline contrast-enhancing volume (P = .02 OS; p=ns PFS), and the achievement of RANO radiographic response (P = .004 OS; P .0001 PFS) were independent predictors of favorable outcomes. Bevacizumab was associated with a mean corticosteroid dose reduction of 2.9 mg/day (49%) after 2 months (P = .001). Conclusion This is one of the first studies to report prognostic factors associated with clinical outcomes in IDH-mutant gliomas treated with bevacizumab. Early radiographic changes may be used to monitor treatment effectiveness, and bevacizumab significantly aids the tapering of corticosteroids in this patient subset.