Tazemetostat (Tazverik) showed clinical activity in patients with advanced epithelioid sarcoma with a loss of INI1/ SMARCB1, according to results of a phase 2 study published in The Lancet Oncology.
More than 90% of tumors in patients with epithelioid sarcoma have lost INI1 expression, according to the article.
In this open-label, phase 2 basket study, 62 patients with epithelioid sarcoma received 800 mg tazemetostat orally twice per day in continuous 28-day cycles until disease progression, unacceptable toxicity, or withdrawal of consent.
At the data cutoff, 15% of patients had an objective response. At a median follow-up of 13.8 months, median duration of response was not reached. At 32 weeks, 26% of patients had disease control, with a median time to response of 3.9 months.
Median progression-free survival and median overall survival were 5.5 months and 19 months, respectively.
Grade 3 or worse treatment-related adverse events included anemia (6%) and weight loss (3%). Treatment-related serious adverse events included seizure (n = 1) and Hemoptysis (n = 1). No treatment-related deaths were reported.
A phase 1b/3 trial of tazemetostat plus doxorubicin in the frontline setting is currently underway, the authors concluded.
Gounder M, Schöffski PP, Jones RL, et al. Tazemetostat in advanced epithelioid sarcoma with loss of INI1/SMARCB1: an international, open-label, phase 2 basket study. 2020; Lancet Oncol. DOI: https://doi.org/10.1016/S1470-2045(20)30451-4