The US Food and Drug Administration has extended its review of AbbVie and Neurocrine’s experimental uterine pain drug elagolix by three months.

The regulator said it needs more time to consider additional information regarding the results of liver function tests provided by AbbVie in connection with the submission for elagolix in endometriosis-associated pain.

The application was assigned a priority review in December last year, but the Agency is now expected to make a decision on the gonadotropin-releasing hormone (GnRH) receptor antagonist by the end of the third quarter.

If approved, elagolix will be the first new oral medical management treatment option for endometriosis-associated pain in more than a decade, the firms noted.

"Based on our review of the data, we remain confident in our New Drug Application for elagolix in the treatment of endometriosis-associated pain," said Michael Severino, executive vice president, research and development and chief scientific officer, AbbVie.

"Elagolix has the potential to be an important new treatment option for women suffering from endometriosis and we are committed to working with the FDA to bring this therapy to patients."

The companies are also developing the drug as a treatment for uterine fibroids.

In March they released clinical data from the ELARIS UF-II trial showing that 76.2 percent of women taking elagolix achieved a clinical response - defined as menstrual blood loss volume of less than 80 mL during month six and a 50 percent or greater reduction in menstrual blood loss volume from baseline to month six - compared to 10.1 percent for placebo.