Efficacy and safety of pazopanib in patients in Japan with primary cutaneous angiosarcoma pretreated with paclitaxel: results of the Japan Clinical Oncology Group single-arm confirmatory trial (JCOG1605)

BACKGROUND: Paclitaxel is a standard first-line chemotherapy for primary cutaneous angiosarcoma. However, there is no established second-line treatment after paclitaxel. OBJECTIVES: The aim of the JCOG1605 study was to evaluate the efficacy and safety of second-line pazopanib for primary cutaneous angiosarcoma. METHODS: This multi-institutional, single-arm, confirmatory trial was conducted in Japan. Patients with cutaneous angiosarcoma not associated with lymphedema or radiation exposure were included in this study. Pazopanib was administered orally at an initial dose of 800 mg, once daily. The primary endpoint was progression-free survival. Retrospective data on second-line docetaxel following first-line paclitaxel treatment were used as a historical control. This trial was registered in the UMIN Clinical Trials Registry (UMIN000031438 [http://www.umin.ac.jp/ctr/index.htm]). RESULTS: Thirty patients were enrolled from 15 institutes and received pazopanib (n = 30). The median progression-free survival and overall survival were 2.8 months (80% CI: 2.1-3.9) and 12.1 months (95% CI: 8.9-28.8), respectively. The response and disease control rates were 31.8% (95% CI: 13.9-54.9) and 63.6% (95% CI: 40.7-82.8), respectively. Twenty-eight (93.3%) and 21 (70%) patients experienced grade ≥2 and grade ≥3 non-hematologic adverse events, respectively. No treatment-related deaths occurred. CONCLUSIONS: The primary endpoint progression-free survival did not meet the predefined threshold. However, the response rate and overall survival were better than expected, and there were no safety issues. Therefore, pazopanib may be a treatment option for patients with paclitaxel-pretreated primary cutaneous angiosarcoma. (231/350 words).