The properties of AbbVie‘s elagolix (ABT-620), an investigative therapy for treating endometriosis and uterine fibroids, were found to be similar in women with and without endometriosis, researchers found.

These findings provide the basis for models to test the safety and effectiveness of elagolix in future studies.

The study, “Population Pharmacokinetics of Elagolix in Healthy Women and Women with Endometriosis,” was published in the journal Clinical Pharmacokinetics.

Elagolix is a gonadotropin-releasing hormone (GnRH) receptor antagonist that blocks the production of ovarian-stimulating hormones and helps reduce the pain associated with endometriosis and heavy menstrual bleeding in patients with uterine fibroids.

The therapy has been shown to treat symptoms in both endometriosis and uterine fibroid patients.

The study set out to examine the population pharmacokinetics of Elagolix in healthy women and women with endometriosis. Population pharmacokinetics is the study of the body’s absorption, distribution, metabolism, and excretion of a medication in a group of people rather than an individual.

The researchers measured the apparent clearance (CL/F), a measure of the body’s ability to eliminate the medication, and the apparent volume of distribution, which is useful to determine the dose necessary to achieve a given concentration of the drug in the blood. They analyzed data from 1,624 women enrolled in five Phase 1 and four Phase 3 studies, including 313 healthy women and 1,311 women with endometriosis.

Factors studied to see if they affected the clearance of elagolix from the body included age; weight; body mass index (BMI); race; ethnicity; albumin; bilirubin and liver enzymes in the blood; tobacco use; alcohol use; organic anion transporting polypeptide (OATP) 1B1 genes (genes that regulate the elimination of drugs from the body); and if the women were located in the U.S. or elsewhere.

Only OATP 1B1 gene status had a statistically significant effect on elagolix clearance. However, the difference did not have a meaningful impact on the body’s exposure to elagolix and would not result in different elagolix dosing recommendations for patients with these genetic profiles.

“None of the other tested covariates, including body weight and BMI, were significantly associated with elagolix pharmacokinetic parameters,” researchers wrote.

“The final population pharmacokinetic model will be utilized for exposure-response models for key elagolix efficacy and safety outcome measures,” they write.

The study was funded by AbbVie and its authors are employees of the company.