Myovant Sciences has reported that the Phase III LIBERTY 1 clinical trial of relugolix combination therapy for uterine fibroids met the primary efficacy endpoint.

The Phase III trial compared the combination therapy to placebo over 24 weeks in 388 patients.

Relugolix is an oral gonadotropin-releasing hormone (GnRH) receptor antagonist. The combination tested in the LIBERTY 1 trial comprised 40mg relugolix, 1mg estradiol and 0.5mg norethindrone acetate.

According to the trial results, 73.4% of women treated once daily with relugolix combination experienced a greater reduction in menstrual blood loss volume from baseline, compared to 18.9% of the patients in placebo arm.

On an average, subjects on relugolix combination therapy experienced an 84.3% reduction in menstrual blood loss.

Apart from the reduction in menstrual blood loss, the combination therapy maintained bone mineral density at levels comparable to placebo over 24 weeks. Relugolix combination was also observed to be generally well-tolerated.

The trial also met six key secondary endpoints. It demonstrated statistical significance for mean change in menstrual blood loss from baseline to week 24, compared to placebo.

Other key secondary endpoints met by the combination therapy were a decrease in pain at baseline, improvement in quality of life, amenorrhea, improvement in anaemia at baseline and reduction in uterine volume.

The overall incidence of adverse events in the combination and placebo arms was found to be comparable.

“We are incredibly pleased with the positive results of this first Phase III study.”

Myovant Sciences president and CEO Lynn Seely said: “We are incredibly pleased with the positive results of this first Phase III study demonstrating a clinically meaningful response in a high proportion of women while maintaining bone health.

“The improvements in symptoms most relevant to women, such as reduction in menstrual blood loss and pain, and improvement in quality of life are particularly exciting.”

The LIBERTY 2 trial is evaluating relugolix combination in 382 women with uterine fibroids and heavy menstrual bleeding.

Data from this trial is expected to be available in the third quarter of this year.