Myovant beefs up data package in NDA #3, boosting its case for longterm dosing of Pfizer-partnered relugolix

When Pfizer handed over $650 million in cash to partner on Myovant’s relugolix, the pharma giant made clear that the deal — valued at $4.2 billion total — was just as much about the approved indication of prostate cancer as the two women’s health conditions the drug could treat.

A month later, the two companies are offering another glimpse of the therapy’s longterm potential in endometriosis.

The latest data snapshot comes from the extension portion of the Phase III SPIRIT program. Relugolix had hit the co-primary endpoints in both trials, saving a majority of women from severe pain, but investigators wanted to know: Can the effects stretch out to one year?

In short, the answer was yes.

In the study, 84.8% and 73.3% of patients receiving a daily pill combining relugolix, relugolix estradiol and norethindrone acetate reached the threshold for “clinically meaningful pain reductions in dysmenorrhea and non-menstrual pelvic pain, respectively.” On average, they reported an 82.8% reduction on a scale to measure severe menstrual pain — going from 7.4 to 1.3 on an 11-point scale.

“Given the debilitating impact that endometriosis can have on women in their daily lives, often over many years, we need non-invasive and long-term treatment options,” said Linda Giudice, a lead investigator in the trial, adding that the treatment remained well tolerated throughout.

Consistent with earlier observations, the most common side effects were headache, nasopharyngitis and hot flashes. As for the “minimal” bone loss reported through week 24, the companies added, bone mineral density remained stable at week 52.

Myovant CMO Juan Camilo Arjona Ferreira noted that the data build on similarly positive one-year data of relugolix in uterine fibroids, supporting longterm use in both diseases.

The biotech is expecting to hear from the FDA on the uterine fibroid indication by June 1, while the NDA for endometriosis will be filed before or around then.

They have Lynn Seely, veteran drug developer and founding CEO, to thank for steering them into a position of potentially scoring three OKs in just a year and a half. But it will be her successor, former Amgen exec David Marek, who will be spearheading the commercial game plan as they take on AbbVie’s Orilissa in the field.

Thankfully for Myovant — which has always believed it can set itself apart with a better safety profile while maintaining comparable efficacy — it’s no longer a David vs. Goliath battle.

Not only is Pfizer now on board to market relugolix, but Myovant is also one of the Vants that Sumitomo Dainippon grabbed a majority stake in a $3 billion M&A pact engineered by outgoing Vivek Ramaswamy. Just in August, Sumitovant injected another $200 million in the form of a loan to fund the product launches.