Regardless of prior therapy, extent of disease and performance status, patients with epithelioid and other INI1 protein-deficient sarcomas may benefit from combined checkpoint inhibition therapy, according to a study in the Journal of Immunotherapy.
In patients with epithelioid sarcoma, SMARCB1 inactivation is common. This results in a loss of INI1 protein expression and overexpression of the cancer cell growth, which promotes methyltransferase enzyme, EZH2.
In this case report, a 19-year-old man with IV SMARCB1 inactivated epithelioid sarcoma with recurrent end-stage rapidly progressing bulky disease who had failed standard therapy and treatment with an EZH2 inhibitor, was treated with combination ipilimumab and nivolumab.
The patient underwent complete clinical regression of a large (16.1×18.6 cm) soft tissue back mass within 2 weeks of the first cycle of combination checkpoint inhibition therapy. A PET scan 5 months later showed negative complete remission. Checkpoint inhibition therapy was discontinued after a second negative PET/CT scan 3 months after the first.
Pecora A, Halpern S, Weber M, et al. Rapid and complete response to combination anti-CTLA-4 and anti-PD-1 checkpoint inhibitor therapy in a patient with stage IV refractory end-stage epithelioid sarcoma: A case report. J Immunother. 2020;43(9):286-290. DOI: 10.1097/CJI.0000000000000332.