Effective Disease Control After Combinatorial Treatment with a PD-1 Antibody and an mTOR Inhibitor for Recurrent Ovarian Clear Cell Carcinomas: A Case Report and Literature Review

Ovarian clear cell carcinoma (OCCC) is a rare type of epithelial ovarian cancer characterized by a chemoresistant phenotype and high-grade tumor. Conventional therapies for OCCC include surgery and chemotherapy. However, these OCCC treatment approaches are characterized by a high risk of relapse and drug resistance resulting in poor prognosis. Therefore, alternative therapeutic approaches are required to achieve better outcomes. In this study, a PIK3CA p.R88Q mutation and PD-L1 expression with a tumor proportion score of 10% was explored in a patient who presented with rapid recurrence after surgery and unsuccessful postoperative chemotherapy. Based on the clinical condition and the patient preference, she was administered a novel combinatorial therapy comprising mTOR inhibitor everolimus, which is a well-known and potent inhibitor of the PI3K/AKT signaling pathway, and the anti-PD-1 antibody toripalimab. Treatment with this combinatorial therapy showed good prognosis, with more than eight months of disease control, and no severe adverse events were observed. The findings of this study provide a novel and effective strategy for OCCC patients. To the best of our knowledge, this is the first study to report a new combination regimen of immunotherapy (everolimus plus toripalimab) for solid tumors. Everolimus is not only an antitumor targeted drug but also an immunosuppressant; it’s combination with immunotherapy is controversial. This is the first report to demonstrate that it has a synergistic effect.