Efficacy and safety of bevacizumab in recurrent sex cord-stromal ovarian tumors: Results of a phase 2 trial of the Gynecologic Oncology Group

Background The Gynecologic Oncology Group conducted this phase 2 trial to estimate the antitumor activity of bevacizumab and to determine the nature and degree of toxicity in patients with recurrent sex cord-stromal tumors of the ovary. Methods A prospective, multi-institutional cooperative group trial was performed in women with recurrent, measurable ovarian stromal tumors. Patients were allowed to have unlimited prior therapy, excluding bevacizumab. Bevacizumab 15 mg/kg was administered intravenously on day 1 of every 21-day cycle until patients developed disease progression or adverse effects that prohibited further treatment. The primary endpoint was the response rate (RR). Inhibin A and B levels were measured before each cycle, and the values were examined in relation to response and progression. Results Thirty-six patients were enrolled, and all were eligible and evaluable. Patients received a median of 9 cycles of treatment (range, 2-37 cycles). Six patients (16.7%) had partial responses (90% confidence interval, 7.5%-30.3%), 28 patients (77.8%) had stable disease, and 2 patients (5.6%) had progressive disease. This met the criterion for declaring the regimen active. The median progression-free survival was 9.3 months, and the median overall survival was not reached in during reporting period. Two grade 4 toxicities occurred, including hypertension and proteinuria; and the most common grade 3 toxicities were hypertension (n = 5) and pain (n = 5). Inhibin A and B values were lower in patients who responded to treatment. Conclusions Bevacizumab has activity in the treatment of recurrent sex cord-stromal tumors of the ovary, and its toxicity is acceptable. Further investigation is warranted.