An open-label multicenter phase II study of bevacizumab for the treatment of angiosarcoma.

10522 Background: The limited therapeutic options and dismal prognosis for patients (pts) with angiosarcomas (AS) provide a strong rationale for the evaluation of new therapies. Preclinical studies in AS tumor models have shown antitumor effects of antiangiogenic agents. We conducted a phase II study to determine the antitumor effect of bevacizumab in AS. METHODS The study was a two-stage design in which patients with newly diagnosed or relapsed/refractory AS and epithelioid hemangioendotheliomas were treated with bevacizumab 15 mg/kg IV every 3 weeks. Treatment was continued until progression or unacceptable toxicity. Response was assessed by RECIST criteria. RESULTS To date, of 29 pts enrolled, 28 received treatment. Baseline data on 29 pts are: M:F= 12:17 and median age 62 (range 18-94). Three pts are not evaluable (1 too early, 2 full treatment not given). Among 26 pts evaluable for response so far: 3 have PR (range 3-16 cycles), 13 have SD (3-32 cycles) and 10 have PD. ORR 3/26 (12%). After 141 cycles of therapy, only 1 grade 4 adverse event occurred (thrombocytopenia) and 5 patients experienced a grade 3 adverse event (anemia, pleural effusion, congestive heart failure, pain, headache, and nausea). CONCLUSIONS Bevacizumab monotherapy for AS resulted in a response rate of 12% and tumor stabilization achieved by 62% of pts. Further studies with bevacizumab in combination with chemotherapy should be explored in this disease. No significant financial relationships to disclose.