The Food and Drug Administration has approved elagolix (Orilissa) for oral treatment of moderate to severe pain associated with endometriosis, announced AbbVie and Neurocrine Biosciences; this approval makes it the first such treatment in more than a decade. It is expected to be available in the United States in early August.
Elagolix is a gonadotropin-releasing hormone (GnRH) antagonist and the first and only one developed specifically for managing this kind of pain.
The approval is based on two 6-month, randomized, double-blind, placebo-controlled phase 3 trials that compared a total of 952 adult women treated with either elagolix with 734 treated with placebo. All of the women experienced moderate to severe endometriosis pain; their ages ranged from 18 to 49 years.
Of the women in the treatment group, 475 were treated with a 150-mg daily dose, and 477 were treated with a 200-mg twice-daily dose. Both treatment groups showed significantly greater mean reductions in pain – both daily menstrual and nonmenstrual pelvic pain – at 6 months. Furthermore, women in the 200-mg twice-daily group also showed statistically significant greater reductions in pain with sex at 3 months, compared with placebo. Altogether, these represent the three most common kinds of endometriosis pain.
The most concerning adverse event associated with elagolix is dose-dependent decreases in bone mineral density; this effect limits treatment to either 150 mg daily for up to 24 months or 200 mg twice daily for up to 6 months. Bone mineral density loss might not be completely reversible, even with treatment cessation. Common adverse events (occurring in at least 5%) included hot flush/night sweats, headache, and nausea. Elagolix is not recommended for women who are or may be pregnant, have osteoporosis, have severe liver disease, or take strong OATP1B1 inhibitors.