Ukmcc-01: A Phase Ii Study Of Pazopanib (Paz) In Metastatic Merkel Cell Carcinoma.

9542Background: The clinical activity of pazopanib, a multi-targeted tyrosine kinase inhibitor, was evaluated in metastatic Merkel Cell Carcinoma (MCC) following a case report demonstrating benefit in a phase II clinical trial. Methods: Patients with histologically confirmed unresectable metastatic MCC received pazopanib at a starting dose of 800mg or 600mg daily, as clinically indicated, following written informed consent. Chemotherapy pre-treated or naive patients were eligible. This was a single arm, multi-center, UK, phase II trial using a Simon two-stage minimax design (p0 = 0.05, p1 = 0.20, alpha = 0.15, power = 90%). The primary outcome was clinical response rate measured by RECIST. In order to progress to the second stage, 1 responder was required in the first 19 patients, with; 3 or more responders in 25 patients required to confirm adequate activity for further clinical investigation. Results: Seventeen patients with histologically proven MCC were recruited between Jan-13 and Jan-16, when the tr...