A drug candidate once shelved by Takeda Pharmaceutical (NYSE: [[ticker:TAK]]) has found new life within Roivant Sciences spinout Myovant as a potential once-daily oral hormone therapy for patients with advanced prostate cancer.
The Brisbane, CA-based biotech company (MYSE: [[ticker:MYOV]]) reported Tuesday that the drug, relugolix, met the primary goal of a Phase 3 trial, lowering levels of testosterone to what’s known as “castrate levels” through 48 weeks for 96.7 percent of those receiving the investigational medicine. The threshold needed to support an FDA review was 90 percent.
Myovant’s stock price rose 113 percent following the news to $12.92 per share, up from $6.06 apiece as of market close Monday.
In some forms of cancer, hormones fuel tumor growth, and reducing levels of male hormones can make prostate cancers shrink or slow for a time. Relugolix is part of a group of drugs that target gonadotropin-releasing hormone (GnRH) and by doing so, reduce testosterone levels. Other drugs that do this, such as leuprolide acetate—which another group in the Myovant study received, via injection every three months—are already part of the existing drug armamentarium used to slow prostate cancer that has spread or come back after treatment.
However, drugs such as leuprolide acetate, which work by desensitizing GnRH receptors, cause a surge in testosterone levels before suppression kicks in. The effect, known as a “clinical flare,” can cause a range of unwanted side effects, including heightened cardiovascular risk. This wasn’t seen in those receiving the investigational Myovant drug, which works on the receptors in a different way to reduce testosterone.
In addition to avoiding the flare phenomenon, Myovant is betting patients will find taking a daily pill preferable to receiving periodic injections. But it remains a question which option those with the disease will consider more convenient.
Overall, the rate of side effects experienced by the patients in the two trial groups was comparable. The most commonly reported adverse events among those receiving relugolix were hot flashes, fatigue, constipation, diarrhea, and joint pain. Serious cardiovascular issues were reported in 2.9 percent of men in the relugolix group, compared to 6.2 percent of men who received leuprolide acetate.
Myovant says it plans to ask the FDA to review the results in the second quarter of 2020. Later it plans to talk with regulators in Europe and Japan.
The disease is the second leading cause of cancer death in men in the US, trailing only lung cancer. The American Cancer Society estimates 174,650 new cases of the disease will be diagnosed this year.
Roivant has formed a slew of subsidiaries around the acquisition of compounds previously under the wherewithal of big pharma companies. So far, the spinouts have had mixed results. Earlier this year Irvine, CA-based Urovant Sciences (NASDAQ: [[ticker:UROV]]), which is focused on urologic conditions, saw its stock fall 21 percent after its experimental drug hit the main goals of a Phase 3 study, but failed to achieve statistical significance when compared to a cheaper generic competitor.
The year prior, Axovant Sciences (NASDAQ: [[ticker:AXON]]) ended its efforts to advance the neurodegeneration drug intepirdine, which it had acquired from GlaxoSmithKline (NYSE: [[ticker:GSK]]), after it failed in clinical trials of dementia with Lewy bodies and of Alzheimer’s disease.
Roivant recently inked a deal with Japan’s Sumitomo Dainippon Pharma to sell off its holdings in five of the startups—including its 46 percent stake in Myovant. As part of the deal, Sumitomo says it will provide Myovant a five-year, $350 million loan facility.
The funds will likely come in handy as Myovant looks to commercialize relugolix for other disease areas as well as advanced prostate cancer. It has also been testing the drug as a treatment for women with uterine fibroids and pain associated with endometriosis, and has said it plans to submit data from the uterine fibroids trials to the FDA for review by year’s end.
