AbbVie's (NYSE:ABBV) elagolix has taken another leap toward billion-dollar blockbuster sales status. An FDA decision on elagolix use in endometriosis patients is anticipated soon, and on Tuesday, AbbVie management unveiled data from trials evaluating it in uterine fibroids. If the FDA give the go-ahead for elagoix in endometriosis, and eventually expands its label to include uterine fibroids, the treatent could become the pharmaceutical giant's next top-seller.

Awaiting a decision

AbbVie acquired global rights to elagolix from Neurocrine Biosciences (NASDAQ:NBIX) in 2010, when it had just  successfully completed a phase 2b trial in endometriosis. At the time, AbbVie handed Neurocrine $75 million in upfront cash, and agreed to pay up to $500 million in additional milestones, plus royalties on sales.

Pills spilling out of a prescription bottle form a U.S. dollar sign.


Elagolix is an inhibitor of gonadotropin-releasing hormone (GnRH) that partially suppresses estrogen to maintain it in the low to normal range. This partial suppression feature allows it to reduce the pain associated with endometriosis without the adverse side effects such as significant bone loss that can result from estrogen suppression.

In September 2017, AbbVie submitted elagolix for FDA approval following phase 3 trials showing it reduces three types of endometriosis-associated pain: daily menstrual pelvic pain, non-menstrual pelvic pain, and painful intercourse. The FDA granted the application a priority review, which shortens its target review period to six months from the usual 10. As a result, a decision is expected from regulators in the second quarter. If approved, elagolix would become the first new treatment approved for endometriosis-associated pain in over a decade.

A bigger patient population

About 1 in 10 women suffer from endometriosis during their reproductive years, so an approval could generate annual sales well into the 9-figures. Elagolix's total market opportunity could be even bigger than that: AbbVie released positive data for the drug from the first of two uterine fibroid trials on Feb. 21, and on Tuesday, it reported positive data from the second.

In the first trial, 68.5% of patients receiving elagolix plus low-dose hormone therapy saw reduced heavy menstrual bleeding versus just 8.7% of patients taking a placebo.  Results from the second trial were similar, with 76.2% of patients responding to elagolix versus just 10.1% of patients responding to placebo.

Uterine fibroids have been found to occur in as many as 80% of women by age 50, and while they're often asymptomatic, they can cause pain and heavy bleeding in about 25% of patients. Currently, there are limited non-surgical treatment options available, so an approval in this indication would be welcome.

Tapping into a major market opportunity

AbbVie is putting serious weight into its efforts to develop new drugs that could cushion it against the possible revenue threat from biosimilars to Humira, which accounts for about 65% of its $28.2 billion in annual sales. Humira's EU patents expire later this year, and in the wake of a U.S. patent decision last fall, it's likely that biosimilars to Humira will go on sale domestically in 2023. 

Overall, industry watchers think elagolix could contribute about $1.2 billion to annual sales in 2022. If those estimates are correct, then it could be a key contributor to the company's post-Humira success.

Todd Campbell has no position in any of the stocks mentioned. His clients may have positions in the companies mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.