Injectable GnRH agonists are effective options as second-tier treatments for endometriosis-related dysmenorrhea, but patients are at risk of developing postmenopausal symptoms such as hot flashes, insomnia, spotting, and decreased libido. “One advantage to that is, over the years and particularly something that I’ve done with my endometriosis-related dysmenorrhea, is to utilize add-back with these patients,” said Dr. Miller, who noted that patients on 2.5 mg of norethindrone acetate and 0.5 mg of ethinyl estradiol“do very well” with that combination of add-back therapy.
Elagolix is the most recent second-tier treatment option for these patients, and was studied in the Elaris EM-I and Elaris EM-II trials in a once-daily dose of 150 mg and a twice-daily dose of 200 mg. In Elaris EM-1, 76% of patients in the 200-mg elagolix group had a clinical response, compared with 46% in the 150-mg group and 20% in the placebo group (N Engl J Med. 2017 Jul 6.). However, patients should not be on elagolix at 200 mg for more than 6 months, while patients receiving elagolix at 150 mg can stay on the treatment for up to 2 years.
Patients taking elagolix also showed postmenopausal symptoms, with 24% in the 150-mg group and 46% in the 200-mg group experiencing hot flashes, compared with 9% of patients in the placebo group. While 6% of patients in the 150-mg group and 10% in the 200-mg group discontinued because of adverse events, 1% and 3% of patients in the 150-mg and 200-mg group discontinued because of hot flashes or night sweats, respectively. “Symptoms are well tolerated, far different than in comparison with leuprolide acetate and GnRH agonists,” said Dr. Miller.
There also is a benefit to how patients recover from bone mineral density (BMD) changes after remaining on elagolix, Dr. Miller noted. In patients who received elagolix for 12 months at doses of 150 mg and 200 mg, there was an increase in lumbar spine BMD recovered 6 months after discontinuation, with patients in the 150-mg group experiencing a recovery close to baseline BMD levels. Among patients who discontinued treatment, there also was a quick resumption in menses for both groups: 87% of patients in the 150 mg group and 88% of patients in the 200-mg group who discontinued treatment after 6 months had resumed menses by 2 months after discontinuation, while 95% of patients in the 150-mg and 91% in the 200-mg group who discontinued after 12 months resumed menses by 2 months after discontinuation.
Dr. Miller reported relationships with AbbVie, Allergan, Blue Seas Med Spa, Espiner Medical, Gynesonics, Halt Medical, Hologic, Karl Storz, Medtronic, and Richard Wolf in the form of consultancies, grants, speakers’ bureau appointments, stock options, royalties, and ownership interests.