ObsEva Launches Two Key Phase 3 Trials to Confirm Efficacy of Linzagolix

ObsEva Launches Two Key Phase 3 Trials to Confirm Efficacy of Linzagolix

ObsEva announced the initiation of two key Phase 3 trials to confirm the safety and efficacy of its therapy linzagolix for endometriosis-associated pelvic pain and to support the therapy’s approval in the U.S. and Europe.

“We are very pleased to announce the initiation of pivotal Phase 3 trials for linzagolix in endometriosis-associated pain, which if successful will form the basis for our registration in the U.S. and Europe for that indication. We believe that linzagolix has the potential to be a best-in-class oral GnRH antagonist, providing women with dosing options both with and without [add-back therapy] to manage their condition ,” Dr. Ernest Loumaye, co-founder and CEO of ObsEva, said in a press release.

Linzagolix (formerly OBE2109) is an experimental oral therapy being developed by ObsEva to ease symptoms of pain and heavy menstrual bleeding associated with endometriosis and uterine fibroids.

Belonging to the class of GnRH receptor antagonists, it works by blocking the activity of  gonadotropin-releasing hormone (GnRH), key for regulating the levels of estrogen and other sex hormones. This results in lower estrogen levels, expected to stop the monthly menstrual cycle and prevent the growth of new endometrial lesions.

ObsEva’s Phase 3 clinical program includes the EDELWEISS 2 and 3 trials, both randomized, placebo-controlled, double-blind studies with a duration of six months.

The trials are designed to confirm the efficacy and safety of linzagolix in patients with moderate to severe endometriosis-associated pain. They will test two doses of linzagolix — a 75 mg daily dose alone and a 200 mg daily dose combined with hormonal add-back therapy (ABT).

Add-back therapy is the addition of a very low dose of hormonal therapy with either estrogen or progesterone, usually taken by women on Lupron Depot (leuprolide acetate) to prevent side effects of low estrogen, such as osteoporosis or bone loss. As 200 mg of linzagolix completely inhibits estrogen production, it requires some add-back estrogen supplementation to avoid the same side effects.

At the end of each trial, patients may enter an extension study for another six months, in which they will be given linzagolix only. After this treatment period, there will be a follow-up (off linzagolix) of six months more.

Taken together, ObsEva expects to enroll 900 patients in the U.S. and Canada (EDELWEISS 2) and in the U.S. and Europe (EDELWEISS 3).

The initiation of these trials follows the positive results obtained in ObsEva’s Phase 2b EDELWEISS study (NCT02778399), where linzagolix was significantly superior for easing endometriosis pain compared to a placebo at all doses tested (50 mg, 75 mg, 100 mg, or 200 mg daily).

The intermediate dose of 75 mg was the most effective at easing pelvic pain, with 70.8 percent of patients reporting at least a 30 percent reduction. The highest dose of 200 mg was the most effective at easing menstrual cramps.

Latest data from the follow-up and extension parts of the trial also indicate that linzagolix is capable of lessening pelvic pain and increasing the quality of life in a long-term manner.