Clinical outcomes of the combination of bevacizumab and ttfields in patients with recurrent glioblastoma: Results of a phase II clinical trial.

2537 Background: Clinical trials of bevacizumab monotherapy and TTFields monotherapy have shown activity but limited clinical benefit in patients (pts) with recurrent glioblastoma (GBM), with median progression-free survival (PFS) of 2-4 months and median overall survival (OS) of 6-9 months with either treatment modality. In a single-arm phase II clinical trial, the efficacy of the combination of bevacizumab and TTFields in pts with recurrent GBM was investigated. Methods: Pts with histologically confirmed GBM or other grade IV gliomas, who had disease progression after chemoradiation were enrolled in a phase II trial of the combination of bevacizumab and TTFields. Bevacizumab was given at a dose of 10 mg/Kg intravenously every 2 weeks and TTFields was worn by the pts continuously for more than 18 hours per day. Treatment was continued until disease progression or unacceptable toxicity. The primary endpoints were PFS at 6 months and OS at 12 months. Survival outcomes were assessed using the Kaplan-Meier method and compared by log rank test. Treatment-related adverse events were reported according to CTCAE, v4.0 criteria. Results: From April 2013 to December 2017, 25 pts were enrolled and 23 were evaluable: 18 (78%) men and 5 (22%) women, median age 60 years (range 17–78). 21 pts were Caucasian, 1 was African American and 1 of unknown race. After a median follow up of 31.6 months (range: 4.1-59.0 months), 21 out of 23 pts died (4 women and 17 men). The median PFS was 4.1 months (95%CI, 3.6-9.5) and the median OS was 10.5 months (95% CI, 8.2-14.9). The PFS rate at 6 and 12 months were 33% and 19%, respectively. The OS rate at 6 and 12 months were 82% and 46%, respectively. Women had better OS and PFS compared to men, however, the difference was not statistically significant which can be due to the small study population (table). Grade 3 and 4 toxicities considered definitely or probably related to the treatment included hypertension (n = 1) and cerebral infarction (n = 1). Other reported grade 3-4 toxicities (n = 7) included cough, dysphagia, muscle weakness, hyperglycemia, psychosis, seizure, lymphopenia, transaminitis, and muscle weakness considered unlikely to be treatment-related. Conclusions: The combination of bevacizumab and TTFields in is safe and feasible and has clinical efficacy in pts with recurrent GBM. Clinical trial information: NCT01894061 . [Table: see text]