Relugolix Rapidly Suppresses Testosterone Levels in Advanced Prostate Cancer
by Dr. C.H. Weaver M.D. 6/2020
According to the results of a clinical trial published in the New England Journal of Medicine comparing standard Lupron (leuprolide) therapy to relugoix in patients with advanced prostate cancer, relugolix was associated with sustained testosterone level suppression and a lower risk for major cardiovascular adverse events than leuprolide.
Lupron is an injectable luteinizing hormone-releasing hormone agonist which is a standard treatment for achieving androgen deprivation therapy (ADT) in men with prostate cancer. Lupron has some disadvantages including an initial testosterone surge and an associated delay in therapeutic effect. It is known to have longer term side effects to the heart.
Relugolix is an orally administered small molecule, gonadotropin-releasing hormone (GnRH) receptor antagonist As a GnRH receptor antagonist, relugolix binds to and blocks the GnRH receptor (GnRHR) in the anterior pituitary gland. Blocking GnRH receptors decreases the release of gonadotropins – luteinizing hormone (LH) and follicle-stimulating hormone (FSH) – thereby decreasing the downstream production of estrogen and progesterone by the ovaries in women and testosterone by the testes in men
A clinical trial of 930 patients with advanced prostate cancer was conducted to directly compare Lupron and Relugolix. Participants were treated with either relugolix 120 mg once daily or Lupron injection every 3 months for 48 weeks and their outcomes directly compared.
Overall 97% of relugolix treated patients maintained castration levels of testosterone for 48 weeks compared to 89% of Lupron recipients demonstrating the noninferiority of relugolix. In the relugolix and Lupron treatment groups patients castrate levels of testosterone on day 4 were 56.0% and 0%, respectively. The incidence of major cardiovascular adverse events was 2.9% and 6.2% with relugolix and leuprolide, respectively.
A lead author of the study Dr. Shore concluded that “In this trial involving men with advanced prostate cancer, relugolix achieved rapid, sustained suppression of testosterone levels that was superior to that with leuprolide, with a 54% lower risk of major adverse cardiovascular events.”
While relogolix offers an oral alternative to Lupron injection and has some potential therapeutic benefits there are some concerns about compliance and convenience between the requirement to take a pill daily compared to an injection every 3-4 months. Based on the results of the HERO clinical trial a New Drug Application has been submitted to the FDA for once-daily, oral Relumina at a dose of 120 mg as treatment of male patients with advanced prostate cancer,
- N Engl J Med. 2020 May 29. Epub ahead of print.