On December 18, 2020, the FDA approved relugolix (Orgovyx; Myovant Sciences), an oral gonadotropin-releasing hormone (GnRH) receptor antagonist, for the treatment of adults with advanced prostate cancer. Relugolix is the first oral androgen-deprivation therapy (ADT) and the first oral GnRH receptor antagonist approved for patients with advanced prostate cancer. The FDA granted relugolix priority review for this indication.
“Today’s approval marks the first oral drug in this class, and it may eliminate some patients’ need to visit the clinic for treatments that require administration by a health care provider,” said Richard Pazdur, MD, FDA’s Director of Oncology Center of Excellence. “This potential to reduce clinic visits can be especially beneficial in helping patients with cancer stay home and avoid exposure during the coronavirus pandemic.”
The American Cancer Society estimated that >190,000 cases of prostate cancer would be diagnosed in the United States in 2020.
The FDA approved relugolix based on data from HERO, a randomized, open-label clinical trial of 622 patients with prostate cancer requiring at least 1 year of ADT because of prostate cancer recurrence after radiation or surgery or patients with newly diagnosed castration-sensitive advanced prostate cancer.
The patients were randomized in a 2:1 ratio to receive 48 weeks of either relugolix 360 mg oral loading dose on the first day, followed by daily oral doses of 120 mg, or to another GnRH receptor antagonist, leuprolide acetate (Lupron Depot) 22.5 mg injection subcutaneously administered every 3 months.
The study’s main efficacy measure was medical castration rate, which was defined as maintaining serum testosterone suppression to castrate levels (ie, <50 ng/dL) by day 29 through 48 weeks of treatment. In the relugolix arm, the medical castration rate was 96.7% (95% confidence interval, 94.9%-97.9%), an almost complete efficacy rate.
The most common (≥10%) adverse reactions reported with relugolix were hot flushes, musculoskeletal pain, fatigue, diarrhea, and constipation. The most common (≥15%) laboratory abnormalities were increased glucose, triglyceride, alanine aminotransferase, and aspartate aminotransferase levels. Decreased hemoglobin level was also observed.
The recommended relugolix dose is an oral loading dose of 360 mg on the first day, then a daily oral dose of 120 mg.