Envafolimab combined with chemotherapy in advanced thymic carcinoma – first clinical experience with a novel subcutaneous programmed death-ligand 1 inhibitor

Thymic carcinoma is rare with poor prognosis, and novel treatments are needed. We report two cases of advanced thymic carcinoma treated with the programmed death-ligand 1 inhibitor envafolimab with chemotherapy (liposomal paclitaxel and cisplatin). Case 1: A 59-year-old woman with metastatic thymic carcinoma (suspected neuroendocrine carcinoma) involving liver and bone received radiotherapy for spinal metastasis followed by eight cycles of envafolimab with liposomal paclitaxel and cisplatin. She achieved a partial tumor response with lesion shrinkage and normalization of liver function and tumor markers without grade 3 or higher adverse events, but later developed disease progression with anterior mediastinal mass enlargement, new left lung metastasis, bilateral pleural effusion, ascites, and pelvic effusion. Because of rapid disease progression and intolerance to further antitumor therapy, the patient died in May 2025. Her progression-free survival (PFS) was 6 months and overall survival was 10 months. Case 2: A 69-year-old man with metastatic thymic squamous carcinoma and multiple comorbidities was treated with definitive radiotherapy to the mediastinal tumor and eight cycles of envafolimab with chemotherapy. He achieved a complete response with tumor reduction and normalized markers. Treatment was well-tolerated without grade 3 or higher adverse events. As of the latest follow-up, PFS was 9 months, and he continues maintenance envafolimab with good tolerance. Both patients achieved PFS (6 and 9 months, respectively) that exceeded the median PFS reported in previous clinical studies using chemotherapy alone (5 months). This combination warrants further investigation in clinical trials.