Myovant Sciences (MYOV), Pfizer (PFE) Announce Positive Data from Phase 3 LIBERTY Randomized Withdrawal Study of Once-Daily Relugolix Combination Therapy in Women with Uterine Fibroids

Myovant Sciences (NYSE: MYOV) and Pfizer Inc. (NYSE: PFE) today announced positive data from the Phase 3 LIBERTY randomized withdrawal study of relugolix combination therapy (relugolix 40 mg plus estradiol 1.0 mg and norethindrone acetate 0.5 mg) in women with uterine fibroids. This study was designed to assess the safety and efficacy of continued treatment with relugolix combination therapy for up to two years.

“Since many women with uterine fibroids spend years struggling to manage their symptoms, there is a critical need for non-invasive long-term treatment options,” said Ayman Al-Hendy, M.D., Ph.D., Professor of Obstetrics and Gynecology, University of Chicago and LIBERTY Program Steering Committee Member. “Data from the LIBERTY randomized withdrawal study demonstrate the potential value of continued treatment for women with uterine fibroids, with those receiving relugolix combination therapy in the study experiencing meaningful symptom relief for up to two years.”

The LIBERTY randomized withdrawal study (N = 229) was a Phase 3 double-blind, placebo-controlled study that enrolled eligible women who completed the LIBERTY long-term extension study. Eligibility criteria included meeting the responder criteria at one year. Responder criteria were defined as a menstrual blood loss volume of less than 80 mL and a 50% or greater reduction from baseline in menstrual blood loss volume during the last 35 days of treatment measured using the alkaline hematin method. Women were randomized at Week 52 to once-daily relugolix combination therapy or placebo for a one-year double-blind treatment period. Women on placebo with relapse of heavy menstrual bleeding during the study were offered re-treatment with open-label relugolix combination therapy. This study, together with the LIBERTY 1, LIBERTY 2, and LIBERTY long-term extension studies, was designed to provide data on the safety and efficacy of treatment with relugolix combination therapy for up to two years.

“We are pleased to see the positive data from the LIBERTY randomized withdrawal study which support the potential benefit of longer-term treatment with relugolix combination therapy,” said Juan Camilo Arjona Ferreira, M.D., Chief Medical Officer of Myovant Sciences, Inc. “We look forward to making the full data available at a future medical congress.”

“Uterine fibroids can affect many women during their lifetime with uncomfortable symptoms, such as heavy menstrual bleeding,” said James Rusnak, M.D., Ph.D., Senior Vice President, Chief Development Officer, Internal Medicine and Hospital, Global Product Development at Pfizer. “We believe that these study results offer encouraging data in support of longer-term efficacy in women suffering from uterine fibroids.”

The LIBERTY randomized withdrawal study met its primary endpoint with 78.4% of women who continued on relugolix combination therapy achieving the sustained responder rate (menstrual blood loss < 80 mL) through Week 76 compared with 15.1% of women who discontinued treatment and initiated placebo at Week 52 (p < 0.0001). All three key secondary endpoints in the LIBERTY randomized withdrawal study were also achieved, including sustained responder rate at two years (Week 104), time to relapse of heavy menstrual bleeding, and amenorrhea rate (all p < 0.0001). Through two years, 69.8% of women who continued on relugolix combination therapy remained responders. 88.3% of women who discontinued treatment at Week 52 relapsed with heavy menstrual bleeding, with a median time of return to heavy menstrual bleeding of 5.9 weeks.

Bone mineral density was maintained through two years in the subset of women continuously treated with relugolix combination therapy (N = 31). The incidence of adverse events over one additional year of treatment was consistent with those observed in prior studies, with no new safety signals observed. The most commonly reported adverse event in at least 10% of women treated with relugolix combination therapy was nasopharyngitis.

Relugolix combination tablet (relugolix 40 mg, estradiol 1.0 mg, and norethindrone acetate 0.5 mg) is under review by the U.S. Food and Drug Administration (FDA) for the treatment of women with uterine fibroids, with a decision expected by the June 1, 2021 target action date.

Myovant Sciences Conference CallMyovant will hold a webcast and conference call at 8:30 a.m. Eastern Time / 5:30 a.m. Pacific Time today, March 24, 2021. Investors and the general public may access a live webcast of the call by visiting the investor relations page of Myovant’s website at investors.myovant.com. Institutional investors and analysts may also participate in the conference call by dialing 1-800-532-3746 in the U.S. or +1-470-495-9166 from outside the U.S.

The webcast will be archived on Myovant’s Investor Relations website following the call.

About the Phase 3 LIBERTY Program in Uterine Fibroids The Phase 3 clinical program for uterine fibroids consisted of two multinational, replicate pivotal clinical studies (LIBERTY 1 and LIBERTY 2) of relugolix combination therapy (relugolix 40 mg plus estradiol 1.0 mg and norethindrone acetate 0.5 mg) in women with heavy menstrual bleeding associated with uterine fibroids for 24 weeks. Eligible women who completed the LIBERTY 1 or LIBERTY 2 studies were offered the opportunity to enroll in an active treatment extension study in which all women received relugolix combination therapy for an additional 28-week period for a total treatment period of 52 weeks, designed to evaluate the safety and efficacy of longer-term treatment. Upon completion of this 52-week total treatment period, eligible women could elect to participate in a second 52-week randomized withdrawal study designed to provide two-year safety and efficacy data on relugolix combination therapy and to evaluate the need for maintenance therapy. Across studies, a response was defined as a menstrual blood loss volume of less than 80 mL and a 50% or greater reduction from baseline in menstrual blood loss volume during the last 35 days of treatment measured using the alkaline hematin method.

LIBERTY 1 and 2 met their primary endpoints (p < 0.0001) with 73.4% and 71.2% of women receiving relugolix combination therapy achieving the responder criteria compared with 18.9% and 14.7% of women receiving placebo at 24 weeks, respectively. On average, women receiving relugolix combination therapy in both studies experienced an 84.3% reduction in menstrual blood loss from baseline at Week 24 (p < 0.0001). Bone mineral density was comparable between the relugolix combination therapy and placebo groups in LIBERTY 1 and 2. The distribution of the change in bone mineral density, including outliers, was similar for the relugolix combination therapy and placebo groups at 24 weeks, as assessed by dual energy x-ray absorptiometry (DXA). The overall incidence of adverse events in the relugolix combination and placebo groups was comparable in both studies.

The open-label extension study also met its primary endpoint with relugolix combination therapy demonstrating an 87.7% response rate at one year, showing the durability of the response observed in LIBERTY 1 and 2. In addition, women experienced, on average, an 89.9% reduction in menstrual blood loss from baseline at Week 52. Changes in bone mineral density through one year, as assessed by DXA every three months, were consistent with LIBERTY 1 and 2. The incidence of adverse events over one year was consistent with that observed in LIBERTY 1 and 2, with no new safety signals observed.

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