Good and sustained response to pembrolizumab and pazopanib in advanced undifferentiated pleomorphic sarcoma: a case report

BACKGROUND: Conventional cytotoxic agents and pazopanib are approved for advanced soft tissue sarcomas but have low response rates and modest survival benefits. Recently, immune checkpoint inhibitors have shown clinically meaningful activity. The combination of pazopanib and immunotherapy has shown synergism in various other malignancies but has not been fully explored in advanced soft tissue sarcomas. CASE PRESENTATION: A 63 year old woman with metastatic undifferentiated pleomorphic sarcoma progressed after two lines of palliative combination chemotherapy—doxorubicin with olaratumab, and gemcitabine with docetaxel. In view of significant symptoms, she was treated with pazopanib in combination with pembrolizumab. She had remarkable radiological and clinical improvement, with a manageable toxicity profile and an ongoing response at ten months of therapy. CONCLUSIONS: Undifferentiated pleomorphic sarcoma is an immunologically active subtype of soft tissue sarcoma, which is particularly amenable to immune checkpoint inhibitors. Pazopanib with immune checkpoint inhibitors is a well-tolerated, yet hitherto underexplored combination that may offer significant clinical benefit in advanced sarcomas—this finding warrants further evaluation in clinical trials.