Linzagolix – Uterine Fibroids

In 2015, ObsEva in-licensed Linzagolix for the treatment of endometriosis from Kissei Pharmaceutical Co. 

Linzagolix is a a novel, orally administered GnRH receptor antagonist antagonist that potentially provides effective management of heavy menstrual bleeding (HMB) associated with uterine fibroids (UF) while mitigating bone mineral density loss and other adverse effects typically associated with currently approved treatments. Unlike marketed GnRH agonists, Linzagolix has the potential to be administered orally once a day, with symptoms relieved within days, while potentially mitigating the initial worsening of symptoms often associated with GnRH agonist treatments. Linzagolix has the potential to dose-dependently lower estradiol levels hence maintaining such levels within an optimal range to mitigate patient bone mineral density loss. Linzagolix has the potential to allow patients to receive the relief needed to live normal lives again and enhance their quality of life with fewer side effects and complications requiring doctor’s visits or surgery.

In a Phase 2a clinical trial, which included a subgroup of patients with both endometriosis and UF, Linzagolix provided significant, dose-dependent decreases in serum LH and estradiol levels in UF patients. This resulted in the reduction of bleeding days within the first month of treatment (>90 percent of patients) and anemia correction within three months (>90 percent of patients) of treatment.

The pivotal Phase 3 PRIMROSE 1 and 2 clinical trials of Linzagolix in women with heavy menstrual bleeding (HMB) associated with uterine fibroids (UF) are currently underway in the US and Europee. PRIMROSE 1 and PRIMROSE 2 trials are targeting enrollment of approximately 1,000 women with heavy menstrual bleeding associated with uterine fibroids.  The efficacy and safety of two doses of linzagolix are being studied, including 100mg without ABT and 200mg with ABT. Patient recruitment was completed for PRIMROSE 1 and PRIMROSE 2 trials in Q1 2019 and Q2 2019 respectively.  Six-month primary endpoint data are expected from the PRIMROSE 2 and PRIMROSE 1 trials in Q4 2019 and H1 2020 respectively.