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FDA Clears First New Endometriosis Treatment In 10 Years

Millions of women worldwide suffer severe pain from endometriosis. Shidlovski/Shutterstock

The US FDA has approved a hormone-modulating drug called elagolix for the treatment of endometriosis-related pain. Manufactured by the pharmaceutical giant AbbVie, the daily oral therapy will be marketed under the brand name Orilissa and should be available as soon as next month.

It is estimated that between 1 in 10 and 1 in 100 women will experience endometriosis during their menstrual years, and about 176 million women worldwide are currently affected. The disease is characterized by the growth of uterine-lining tissue in abnormal locations of the female reproductive tract. These islands of endometrium often cause crippling pelvic pain because, like the actual uterine lining, they become inflamed by menstrual hormone fluxes. Some women experience pain only during certain times of their cycles; however, some women are in pain nearly constantly because the tissue lesions are pulling on nearby organ structures or have gotten large enough to develop their own nerve endings. Untreated lesions may lead to infertility.


Though there are several options available for managing the growths themselves, there are no drugs that specifically target the pain, forcing patients to seek relief with the typical arsenal of NSAIDs and other painkillers.

Due to the large unmet need for new endometriosis medications – none have been introduced in the past decade – and promising clinical trial data, the FDA chose to expedite elagolix’s new drug application (NDA), a designation known as priority review, back in October 2017.

The decision to approve the drug stems largely from the results of the two most recent phase 3 studies, conducted in nearly 1,700 women with moderate to severe endometriosis pain. Subjects who received 150 mg of elagolix once a day for 24 months, or 200 mg twice a day for six months, had significant reductions in menstrual pelvic pain, non-menstrual pelvic pain, and pain during sex.

Elagolix works by blocking the actions of gonadotropin-releasing hormone GnRH, thus inhibiting the cascade of signaling that leads to estrogen production. Unfortunately, decreased reproductive hormone levels are known to reduce bone mineral density (BMD), and the elagolix trials confirmed that there is indeed a dose-dependent loss of BMD. For this reason, the drug is not approved for long-term use.


"Women with endometriosis may undergo multiple medical treatments and surgical procedures seeking pain relief, and this approval gives physicians another option for treatment based on a woman's specific type and severity of endometriosis pain," said Dr Hugh Taylor, a study investigator from Yale University School of Medicine, in the Abbvie statement.

As with other hormone therapies for endometriosis, elagolix interferes with many types of birth control, and patients that are trying to avoid pregnancy will need to use hormone-free contraceptives such as condoms. Abbvie also warns that women trying to get pregnant should not take the medication.


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