Abstract 88P
Background
Epithelioid sarcoma (ES) is a rare sarcoma subtype characterized by the loss of expression of INI1 (SMARCB1). Conventional chemotherapy and tazemetostat have moderate activity in ES. There have been anecdotal reports of responses to checkpoint inhibitors in epithelioid sarcoma (Pecora et al., 2020) (Blay et al., 2020).
Methods
A retrospective search of a prospective database was used to identify ES patients treated with checkpoint inhibitor therapy at the Royal Marsden between April 2021 and December 2023. Patients received combination ipilimumab (1mg/kg) and nivolumab (3mg/kg) every 3 weeks for 4 cycles followed by nivolumab 240 mg every 2 weeks through a compassionate access program. Progression free survival (PFS) was estimated from Cycle 1, Day 1 to disease progression or death and duration of response (DOR) from the date of first response to disease progression or death.
Results
Six patients were treated, 1 female and 5 males with a median age of 41 years. Ipilimumab/nivolumab was administered as 2nd-line therapy in 4 patients and 4th and 5th line respectively for the other 2 patients. Five patients were previously treated with tazemetostat and 3 had prior treatment with doxorubicin. Four patients had stable disease and 2 partial response as best response by RECIST. Four patients have developed progressive disease and 3 patients have died. The median PFS were 6.63 (95% CI, 2-11.27) months and the median DOR 4.1 (95% CI, 1.23-6.97) months respectively. Three patients are still on treatment, one of them has developed oligoprogression in the brain. Three patients developed G2 hypothyroidism, one G2 transaminitis and one G3 transaminitis. The patient with G2 transaminitis, discontinued treatment after developing G2 colitis. One patient developed G3 hypoadrenalinism. Three patients had more than one immunotherapy-related toxicities. There were no treatment related deaths.
Conclusions
Ipilimumab plus nivolumab is safe with encouraging efficacy in patients with epithelioid sarcoma. Further investigation is warranted, ideally in the context of a prospective clinical trial.
Clinical trial identification
not applicable
Editorial acknowledgement
not applicable
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.