Durable response to pembrolizumab plus axitinib in platinum-resistant ovarian clear cell carcinoma: A case report.

Introduction: Ovarian clear cell carcinoma (OCCC) is a rare and aggressive histologic subtype of epithelial ovarian cancer characterized by intrinsic chemoresistance and limited treatment options in the platinum-resistant setting. Immune checkpoint inhibitors and VEGFR-targeted therapies have demonstrated synergistic activity across multiple malignancies, though their role in OCCC remains incompletely defined. Axitinib is a selective VEGFR1-3 tyrosine kinase inhibitor approved for renal cell carcinoma but not OCCC. Case Presentation: We report a 39-year-old female with FIGO stage IVA platinum-resistant OCCC who achieved durable disease control with pembrolizumab plus axitinib, despite prior mixed response to first-line therapies including bevacizumab. Tumor profiling demonstrated microsatellite stability, low tumor mutational burden, PD-L1 expression (TPS 5%), ARID1A mutation, and TP53 alteration. Serial imaging demonstrated sustained radiographic improvement followed by imaging findings suspicious for disease progression after approximately 23 months of disease control. Conclusion: This case highlights the potential therapeutic relevance of VEGFR inhibition combined with immune checkpoint blockade in platinum-resistant OCCC. In a setting with limited effective options, this combination strategy may provide meaningful clinical benefit in selected patients.