Tislelizumab combined with chemotherapy in advanced thymic tumors.

Abstract

e20139 Background: Thymic tumors refer to tumors derived from thymic epithelial cells, including thymoma and thymic carcinoma. Most cases in advanced stages when detected, and treatment is still controversial. Since 2018, immunotherapy has gradually been used for a variety of solid tumors and the curative efficacy has been notable. The efficacy of immunotherapy is increasingly improved with the increased expression of programmed death-ligand 1 (PD-L1) by tumor cells. The thymus is an immune-rich organ. PD-L1 expression ranges from 23% to 92% in thymoma, and from 36% to 100% in thymic carcinoma. Thus, immunotherapy has been implicated as having broad prospects in the treatment of thymic tumors. Tislelizumab is an inhibitor of PD-1, which has shown preliminary anti-tumor effects in various solid tumors. The combination of immunotherapy and chemotherapy has produced excellent anti-tumor activity for various types of tumors. However, there is a lack of clinical trial data to support the application of tislelizumab for the treatment of advanced thymic tumors. In this article, the efficacy and safety of tislelizumab combined with chemotherapy were analyzed in eight patients with advanced thymic tumors to provide data for the use of this monoclonal antibody as first-line treatment of advanced thymic tumors. Methods: Here, after obtaining fully informed consent, we report cases involving eight patients with advanced thymic tumors treated with tislelizumab combined with chemotherapy. The clinical characteristics, lesion changes, treatment process, drugs used, drug efficacy, complications or adverse reactions were recorded and followed up to evaluate the efficacy and safety of tislelizumab combined with chemotherapy in the treatment of advanced thymic tumors. Results: This article reports eight cases of advanced thymic tumor treated with tislelizumab combined with chemotherapy. Two patients received tislelizumab combined with chemotherapy as first-line treatment, and the remaining six patients were treated with tislelizumab after poor response to chemotherapy. Five patients achieved a partial response to the combined treatment. Of these, the partial response was retained in three patients after switching to tislelizumab monotherapy. The remaining three patients displayed stable disease after the combined treatment. There were no serious immune-related adverse events during treatment. The side effects of tislelizumab combined with chemotherapy were well tolerated. Conclusions: No clinical study of immunotherapy combined with standard chemotherapy as first-line treatment for advanced unresectable or metastatic thymic epithelial tumors has been described. This article provides strong evidence for the early application or even first-line use of tislelizumab combined with chemotherapy for advanced thymic epithelial tumors. More clinical studies are needed to evaluate the efficacy and safety of tislelizumab in thymic tumors.