Elagolix shows promising results for long term treatment of endometriosis

Elagolix has the potential to be an important treatment option for long term medical treatment for Endometriosis, reports the results of two replicate, randomized double blind, phase III studies. The paper was presented at the 13th World Congress on Endometriosis in Vancouver, Canada and simultaneously published in the New England Journal of Medicine.

Elagolix is an oral gonadotropin-releasing hormone (GnRH) receptor antagonist. It results in rapid, reversible, dose-dependent inhibition of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion, leading to reduced ovarian production of the sex hormones, oestradiol and progesterone, while on therapy.

Medical management of Endometriosis requires treatment for extended period and physicians currently have very limited options in this regard. Treatment with gonadotropin-releasing hormone (GnRH) agonists, such as leuprolide acetate cannot be extended beyond 6 months because of osteoporosis and sever vasomotor symptoms.

These two-trial recruited 1,689 premenopausal women between the ages of 18 and 49 years, who had endometriosis and suffered from moderate to severe pain and had a z score of more than -1.5 for bone mineral density at the lumbar spine, femoral neck, or total hip. The study participants were from 151 sites in the United States and Canada from July 2012 through May 2014 and for Elaris EM-II at 187 sites on five continents from November 2013 through July 2015.

Each woman was randomly assigned to receive 150 mg of elagolix once daily (lower-dose group), 200 mg of elagolix twice daily (higher-dose group), or placebo.

The results were evaluated in terms of proportion of women who had clinical response for dysmenorrhea and non-menstrual pain after 3 months of treatment. Other relevant clinical parameters tested were dyspareunia, use of rescue NSAIDs and opioids, dyspareunia and non-menstrual pain at 6 months of treatment.

In both the trials, women showed statistically significant response in terms of dyspareunia and non-menstrual pain at 3 months of treatment as compared to placebo. The response was sustained at 6 months of treatment for these two parameters.

Women who received the higher dose of elagolix (200 mg twice daily) had significantly better results with respect to the use of rescue analgesic agents at 3 months and 6 months, dyspareunia at 3 months, and rescue opioid use at 3 months than did those receiving placebo.

Treatment with Elagolix improved the quality of life based on the 30-item Endometriosis Health Profile dimensions in both groups as compared to placebo.

Because of its hypoestrogenic effect, more than 70% women in the trial reported adverse effect including hot flushes and changes in bone mineral density and lipid levels but the frequency differed significantly between the higher and lower dose groups.

Professor Hugh Taylor, lead author of the resulting paper said, “The idea that we now have choices with regards to the extent of oestrogen suppression is attractive, as it allows us to provide a more personalised and individualised therapy.”

“With elagolix – unlike with Lupron (leuprolide acetate)– we can partially suppress oestrogen, unlike the “all or nothing” current approach,” he further added.

Elagolix is currently being investigated in uterine fibroids and endometriosis, and has been studied in over 40 clinical trials totalling more than 3,000 women. AbbVie, the makers of the drug, plans to submit a New Drug Application to the US Food and Drug Administration (FDA) for endometriosis in 2017. 

Full text of the article in NEJM can be accessed here.