The study aimed to address the challenge of increasing response rates of immune checkpoint inhibitors in mCRPC. ESK981 was chosen for its potential to enhance immunotherapeutic responses.
Trial Design and Objectives
The trial involved administering ESK981 orally daily for five days, followed by a two-day break. Nivolumab was given intravenously on the first day of each 28-day cycle.
Primary endpoints:
● 50% reduction in prostate-specific antigen (PSA50)
● Safety
Secondary endpoints:
● Radiographic progression-free survival (rPFS)
● Overall survival (OS)
Disappointing Results and Early Termination
Despite the promising rationale, the trial was terminated early due to futility after enrolling only ten patients. The combination therapy failed to demonstrate significant antitumor activity. Only one patient achieved a maximum PSA decline of 14% from baseline.
The median rPFS was 3.7 months, and the median OS was 9.6 months. While the treatment was generally well-tolerated, some patients experienced Grade 3 adverse events such as fatigue, anemia, and lymphopenia. Notably, no Grade 4 events were observed.
Still positive, I repeat myself that there are 150 companies testing 166 drugs/treatments for prostate cancers (at various stages)...we must get at least 3 to work!
