Linzagolix Under Review for Treatment of Uterine Fibroids

Linzagolix is a novel, oral gonadotropin-releasing hormone (GnRH) receptor antagonist.

The Food and Drug Administration (FDA) has accepted for review the New Drug Application (NDA) for linzagolix for the treatment of uterine fibroids.

Linzagolix is a novel, oral gonadotropin-releasing hormone (GnRH) receptor antagonist. The NDA submission is supported by data from the 52-week, double-blind, placebo-controlled phase 3 PRIMROSE 1 ( Identifier: NCT03070899) and PRIMROSE 2 ( Identifier: NCT03070951) studies, which evaluated the efficacy and safety of linzagolix in 1109 women with heavy menstrual bleeding associated with uterine fibroids. 

Patients were randomly assigned to receive linzagolix 100mg or 200mg once daily or placebo, with or without hormonal add-back therapy (ABT; estradiol 1mg and norethindrone acetate 0.5mg daily). The primary endpoint was the percentage of responders based on menstrual blood loss.

Pooled data from both studies showed that at week 52, linzagolix met the primary endpoint, demonstrating responder rates of 89.3% and 56.4% among women receiving linzagolix 200mg with ABT and linzagolix 100mg without ABT, respectively. Key secondary endpoints including pain reduction, anemia and quality of life were also met.

Findings from a 76-week post-treatment follow-up study showed that off-treatment pain scores remained lower than baseline across all linzagolix treatment arms in PRIMROSE 1 and PRIMROSE 2. Improvements in hemoglobin levels and quality of life were also maintained with linzagolix. Patients treated with linzagolix 100mg and 200mg with ABT also showed evidence of bone mineral density recovery.

“With its unique dosing options, linzagolix has the potential to significantly advance medical options for women,” stated Elizabeth Garner, MD, MPH, Chief Medical Officer of Obseva. “A dosing option without hormonal ABT would be welcomed by the significant number of women who either have contraindications to or a personal preference to avoid the use of estrogen-based therapies, while also providing a dosing option for women in whom hormonal ABT is indicated.”

A Prescription Drug User Fee Act (PDUFA) target date of September 13, 2022 has been set for the application.


Obseva announces US FDA acceptance of New Drug Application for linzagolix. News release. Obseva SA. Accessed November 22, 2021.