Phase II study of border zone stereotactic radiosurgery with bevacizumab in patients with recurrent or progressive glioblastoma multiforme.

Abstract

e14020 Background: This phase II trial was performed to assess the efficacy of Border Zone Stereotactic Radiosurgery (BZ-SRS) with bevacizumab by overall survival (OS) in patients with recurrent or progressive glioblastoma (GBM) following conventional upfront management. Methods: Patients with histologically confirmed GBM with recurrent disease, received prior first-line treatment with surgery/biopsy, fractionated radiotherapy and chemotherapy, ≥ 2 months since completion of radiotherapy and eligible for SRS were enrolled. Bevacizumab 10mg/kg was given one day before, day 14 and then every 14 days until disease progression. 1 to 14 days before BZ-SRS procedure, patients underwent standard brain MRI /MRS. MRS with measurement of choline-to-N-acetyl aspartate index (CNI) area ≥ 3 was targeted for SRS using standard MRI targeting. Results: From 2015-2017, sixteen patients were enrolled. The median age was 62 (range, 48-74Y). 3 of 16 (0.188) participants experienced grade 2 unacceptable toxicity. The median OS was 11.73 months. No survival difference is seen compared with the University of Pittsburgh historical controls. PFS-6 and OS-6 were 31.2% (p=0.00294) and 81.2%(p= 0.058), respectively. Of 13 evaluable for best response: 1 complete response (p=0.077), 4 partial responses (p=0.308), 7 stable disease (p=0.538), and 1 progressed disease (p=0.077). 11 of 16 participants had MRS scans with an estimated probability that MRS changes a treatment plan of 0 (0,0.285). Conclusions: BZ-SRS with bevacizumab was feasible and well tolerated. There is no significant survival benefit using BZ-SRS with bevacizumab compared to historical controls. Secondary analysis revealed a trend toward improved PFS-6, but not OS-6. MRS scans did not result in any changes in SRS treatment plans. Clinical trial information: NCT02120287 .