Swiss biopharmaceutical company ObsEva has submitted a New Drug Application to the US Food and Drug Administration for linzagolix, an oral GnRH antagonist designed to treat uterine fibroids. The drug's unique selling proposition lies in its flexible dosing approach, making it potentially suitable for a broader patient population than existing treatments.
Clinical Impact and Market Positioning
Uterine fibroids affect approximately 5 million women in the United States, with two-thirds receiving inadequate treatment under current therapeutic options. These benign tumors can cause severe symptoms including heavy menstrual bleeding, chronic pain, and abdominal bloating, sometimes leading to infertility. The condition results in approximately 250,000 hysterectomies annually in the US.
The current treatment landscape includes off-label oral contraceptives and injectable GnRH agonists such as leuprolide acetate and goserelin acetate. Two FDA-approved oral GnRH antagonists - AbbVie/Neurocrine Biosciences' Oriahnn (elagolix) and Myovant/Pfizer's Myfembree (relugolix) - both require concurrent hormone therapy to mitigate side effects like bone loss.
Clinical Trial Results and Dosing Innovation
The FDA submission is supported by positive results from two Phase 3 trials - PRIMROSE 1 and 2. Both studies demonstrated significant reductions in heavy menstrual bleeding compared to placebo across two dosing regimens:
- Low-dose (100mg) linzagolix with add-back hormone therapy
- Higher-dose (200mg) linzagolix with hormone therapy
What sets linzagolix apart is its potential to be the first GnRH antagonist offering treatment options for women who either cannot or choose not to take hormone therapy, while still providing flexibility for those who can tolerate hormonal add-back therapy.
Regulatory Outlook and Commercial Potential
ObsEva, which licensed linzagolix from Japanese pharmaceutical company Kissei in 2015, holds worldwide commercial rights outside Asia. The company is simultaneously pursuing European approval, with an EMA human medicines committee decision expected in the fourth quarter of 2021, potentially leading to EU approval by early 2022.
The drug would enter a market where existing treatments have shown mixed commercial success. Oriahnn generated $121 million in sales through 2020 but showed slower growth in 2021 with $68 million in first-half sales. The more recently approved once-daily Myfembree has emerged as a direct competitor, and linzagolix would add another once-daily option to the therapeutic arsenal.
Treatment Landscape Evolution
The introduction of linzagolix could significantly impact the treatment paradigm for uterine fibroids by offering physicians and patients more flexibility in managing the condition. This adaptability in dosing could potentially expand the number of women who can benefit from GnRH antagonist therapy, particularly those who have contraindications to hormone therapy or prefer to avoid it.
