Oral Relugolix Shows Similar Rate of Castration Resistance-free Survival to IV Leuprolide Acetate in Advanced Prostate Cancer

The results of an additional secondary endpoint from the phase 3 HERO study evaluating oral relugolix in men with advanced prostate cancer showed that relugolix had a similar rate of castration resistance-free survival compared to intravenous leuprolide acetate in men with metastatic disease through 48 weeks.

“These new data from the phase 3 HERO study show that 3 out of 4 men with metastatic prostate cancer remained castration resistance-free through 48 weeks while on oral relugolix, in-line with leuprolide acetate injections, the current standard of care,” said Dan George, MD, a professor of medicine and surgery at the Duke University School of Medicine and HERO program steering committee member, in a press release.

HERO is a randomized, multinational clinical study designed to evaluate the safety and efficacy of relugolix in more than 900 men with androgen-sensitive advanced prostate cancer who required at least 1 year of continuous androgen deprivation therapy. The men were randomized 2 to 1 to receive a single loading dose of relugolix 360 mg followed by relugolix 120 mg once daily, or to treatment with leuprolide acetate 3-month depot injection.

Castration-resistant prostate cancer is defined by disease progression despite achieving testosterone suppression to castrate levels. In the subgroup of men with metastatic disease treated with relugolix, 74% were castration-resistance free through 48 weeks compared to 75% of men treated with leuprolide acetate.

In the secondary endpoint analysis, castration resistance-free survival was defined as the time from first dose to prostate-specific antigen (PSA) progression per the Prostate Cancer Clinical Trials Working Group 3 criteria or death from any cause, according to the study authors.

The incidence of adverse events (AEs) in the subgroup of men with metastatic disease was consistent with what was observed in the primary analysis of HERO with no new safety signals. Relugolix met the primary efficacy endpoint, with 96.7% of men treated with relugolix achieving sustained testosterone suppression to castrate levels through 48 weeks versus 88.8% of men treated with leuprolide acetate.

In addition, relugolix met 6 key secondary endpoints demonstrating rapid and profound suppression of testosterone and PSA response, in addition to improved testosterone recovery after discontinuation of treatment. Men in the relugolix group had a 54% lower risk of major adverse cardiovascular events (MACE) compared with men in the leuprolide acetate group.

In men with a reported history of MACE, the relugolix group had 80% fewer MACE events reported compared to the leuprolide acetate group. The overall incidence of AEs in the relugolix and leuprolide acetate groups was comparable, according to the study authors.

REFERENCE

Myovant Sciences Announces Results of Additional Secondary Endpoint of Castration Resistance-Free Survival from Phase 3 HERO Study of Relugolix in Advanced Prostate Cancer. Myovant Sciences. https://investors.myovant.com/news-releases/news-release-details/myovant-sciences-announces-results-additional-secondary-endpoint. Published September 29, 2020. Accessed September 29, 2020.