Treatment with Tumor-Treating Fields Therapy and Pulse Dose Bevacizumab in Patients with Bevacizumab-Refractory Recurrent Glioblastoma: A Case Series.

Patients with bevacizumab-refractory recurrent glioblastoma multiforme (GBM) have a poor prognosis. We propose that instead of continuing on bevacizumab, patients should switch to treatment with Optune™, a novel antimitotic Tumor-Treating Fields (TTFields) therapy approved in the United States for newly diagnosed and recurrent GBM. This would reserve bevacizumab for subsequent disease progression. In this case series, we describe 8 patients with recurrent GBM who had disease progression on bevacizumab, discontinued bevacizumab treatment, and were treated with TTFields therapy alone. After subsequent radiographic or clinical progression, 5 patients were rechallenged with bevacizumab in a 'pulse dose' fashion, an approach not previously described. Following treatment with TTFields therapy, median overall survival (OS) was 216 days (7.2 months). Median OS from last dose of initial bevacizumab was 237 days (7.9 months), twice that of historical controls for bevacizumab failures, and median OS from the first dose of bevacizumab rechallenge was 172 days (5.7 months). TTFields therapy was well tolerated, with a mean adherence rate of 74.2% (range, 48.2-92.9%). These results support the use of TTFields therapy with pulse dose bevacizumab as an option in patients with refractory GBM.