INTRODUCTION: Limited treatment options exist for patients with thymic epithelial tumors (TETs); this disease progresses even after platinum-based chemotherapy. Only a few prospective studies have investigated potential therapies in this setting. Recent studies have reported that PD-L1 is expressed in up to 70% of patients with TETs. The median progression-free survival even with pembrolizumab was 6.1 months in these relapsed refractory thymomas. However, we present a case of relapsed thymoma with longer PFS benefits using pembrolizumab.
DESCRIPTION
A 54-year-old female was initially diagnosed with locally advanced thymic carcinoma in Jan 2020. She received 3 cycles of gemcitabine + cisplatin followed by concurrent chemoradiation 66Gy/33# with weekly cisplatin. She developed dilated cardiomyopathy and was started on cardiac medications. She had very minimal disease progression in Jan 2021 and was started on OMCT with Tab Endoxan and Tab Methotrexate. After 6 months, due to further metastatic disease progression, she received 9 cycles of Nabpaclitaxel+carboplatin on 4.10.2021.
In Oct 2021, PET CT showed new metastatic nodes in the mediastinum, an interval increase in pericardial effusion and bilateral pleural effusion. She was initiated on pembrolizumab 3 times weekly (from 16/11/2021). After 3 cycles, she had a partial response and was clinically better. She went on to receive 15 cycles, lasting almost 1 year, of pembrolizumab. She further developed oligoprogression in her lymph nodes and hence received 40GY/10 fractions of IMRT. On further disease progression, she was administeredLenvatinib and capecitabine tabs. Finally, she succumbed to illness after 52 months of diagnosis.
CONCLUSION:
Pembrolizumab has shown encouraging antitumor activity in patients with advanced TET. Given the high incidence of autoimmunity, additional studies are needed to identify those who can benefit from pembrolizumab without immune-related adverse events. The median survival of patients with stage 4 thymic carcinoma is around 20-24months; however, this canprolonged to a greater extent with immunotherapy.
