Immune Checkpoint Therapy for Thymic Carcinoma

Thymic carcinoma (TC) is a rare, aggressive cancer that originates from thymus's epithelial cells. It distinguishes itself from other thymic epithelial tumors with its unique pathological structure, clinical behavior, and immune characteristics. Immune checkpoint inhibitors (ICIs) targeting the Programmed cell death protein 1/Programmed cell death protein ligand 1 (PD-1/PD-L1) pathway have shown promise in advanced TC, potentially benefiting from frequent PD-L1 overexpression and abundant CD8⁺ tumor-infiltrating lymphocytes (TILs), despite typically low tumor mutational burden (TMB). While ICI monotherapy can achieve disease control in some patients, its overall efficacy is limited and it is associated with a distinct profile of immune-related adverse events (irAEs) which occur less often than in thymomas. The predictive value of biomarkers-particularly PD-L1 expression-remains uncertain, underscoring the importance of consistent assessment criteria. In this review, we summarize evidence on ICI monotherapy as well as combination approaches that incorporate anti-angiogenic agents, chemotherapy, or dual checkpoint blockade. Emerging therapeutic targets-such as CD70, TIM-3, and B7-H4-are also considered in the context of their potential clinical relevance. Finally, we discuss future directions aimed at improving efficacy, extending response durability, and reducing treatment-related toxicity through biomarker-based patient selection and tailored therapeutic strategies.