Myovant’s Prostate Cancer Drug Relugolix Demonstrates Strong Data in Phase III

Myovant announced additional data from its Phase III HERO trial of once-daily, oral relugolix in advanced prostate cancer. The company presented the data at the American Society of Clinical Oncology (ASCO) Virtual Scientific Program and also published data simultaneously in the New England Journal of Medicine.

The company also submitted a new drug application (NDA) to the U.S. Food and Drug Administration (FDA) for once-daily relugolix combination tablet for the treatment of women with uterine fibroids.

Relugolix is a once-daily, oral gonadotropin-releasing hormone (GnRH) receptor antagonist. It reduces testicular testosterone production, which is known to stimulate prostate cancer growth. It also stimulates ovarian estradiol production, a hormone that stimulates the growth of uterine fibroids and endometriosis.

The Phase III HERO trial met the primary endpoint and demonstrated superiority to leuprolide acetate, AbbVie’s Lupron, in six key secondary endpoints. In the analysis of the primary endpoint, the drug showed 96.7% of men receiving the drug achieved sustained testosterone suppression to castrate levels through 48 weeks, compared to 88.8% of men receiving Lupron.

The secondary data showed “notable differences” in the suppression of testosterone, prostate-specific antigen (PSA) response, and testosterone recovery after discontinuation of treatment.

“A faster effect in lowering testosterone for prostate cancer patients can be clinically significant—likewise, a more rapid testosterone recovery after stopping treatment, could potentially improve a patient’s quality of life,” said Neal Shore, medical director of the Carolina Urologic Research Center, HERO program steering committee member, who presented the data at ASCO and was lead author of the NEJM paper. “Both of these findings could make a meaningful difference in the treatment journey for men with advanced prostate cancer.”

Men receiving relugolix had a 54% lower risk of major adverse cardiovascular events compared to men receiving Lupron.

“Cardiovascular disease is the leading cause of death in men with prostate cancer,” Shore said. “An oral therapeutic option with strong efficacy that also reduces cardiovascular risk compared to that of conventional GnRH agonist therapy would be a critical achievement for men with advanced prostate cancer.”

Myovant submitted the NDA to the FDA for relugolix for prostate cancer in April 2020.

The NDA submission for uterine fibroids is based on positive data from the Phase III LIBERTY program, which included two multinational studies and an open-label extension trial through one year. This was the third regulatory application the company made this year, the first being a Marketing Authorization Application to the European Medicines Agency (EMA) in uterine fibroids. The company is also advancing the Phase III SPIRIT program, which is studying relugolix combination therapy (relugolix, estradiol and norethindrone acetate) in women with pain associated with endometriosis.

“An estimated five million women in the U.S. suffer from symptoms of uterine fibroids, which may include heavy menstrual bleeding, pain, and anemia—yet effective non-invasive treatment options are very limited,” said Lynn Seely, chief executive officer of Myovant. “If approved, we hope to redefine care for these women with relugolix combination tablet, a potential new treatment that demonstrated a predictable and clinically-meaningful reduction in menstrual blood loss while maintaining bone health in the Phase III LIBERTY program.”

Uterine fibroids are noncancerous tumors that grow in or on the muscular walls of the uterus. They are one of the most common reproductive tract tumors in women. Estrogens play a significant role in the regulation of fibroid growth, as well as an individual’s genetic predisposition. Although benign, they can cause symptoms such as heavy menstrual bleeding, pain, increased abdominal girth and bloating, urinary frequency or retention, constipation, pregnancy loss, and infertility.