Bayer's elinzanetant challenges Astellas in menopause market

Bayer has recently released pivotal data from two clinical trials of its investigational menopause drug elinzanetant. This development sets the stage for a competitive showdown with Astellas' already approved drug Veozah (fezolinetant) in the long-neglected market for vasomotor symptoms (VMS) associated with menopause. At the annual meeting of the American College of Obstetricians and Gynecologists (ACOG), Bayer presented results from the OASIS 1 and 2 studies, showing that elinzanetant, a dual neurokinin-1,3 (NK-1,3) receptor antagonist, significantly reduced both the frequency and severity of moderate-to-severe hot flashes in post-menopausal women. About 800 women participated in these studies.

In the OASIS 1 trial, elinzanetant demonstrated significant mean reductions in hot flash frequency compared to placebo—3.29 fewer episodes at week 4 and 3.22 fewer at week 12. Reductions in severity were 0.33 and 0.40, respectively. The OASIS 2 trial yielded similar results, with mean reductions in frequency of 3.04 at week 4 and 3.24 at week 12, and in severity of 0.22 and 0.29. These findings could make elinzanetant a strong competitor to Veozah, an NK-3 receptor antagonist approved last year for VMS treatment. Veozah, also known as Veoza in Europe, showed reductions in hot flash frequency by 2.07 and 2.55 at week 4 and by 2.53 and 2.55 at week 12 in its SKYLIGHT 1 and 2 trials. Severity reductions were about 0.20 and 0.29 in the SKYLIGHT studies.

While the efficacy of both drugs appears closely matched, other factors could influence the market. Bayer highlighted that elinzanetant also met key secondary endpoints in both OASIS trials, significantly improving sleep quality compared to placebo. Mean change from baseline to week 12 on the PROMIS sleep disturbance measure was 5.58 in OASIS 1 and 4.32 in OASIS 2, favoring elinzanetant.

Adverse event-related study dropouts were higher in the elinzanetant groups than the placebo groups in both studies (8.5% vs 6.7% in OASIS 1; 6.5% vs 2% in OASIS 2). However, liver safety, a concern for Veozah due to potential increases in hepatic serum transaminase levels, appears to be less of an issue for elinzanetant. Researchers reported no cases of drug-induced liver injury or incidences of endometrial hyperplasia or malignant neoplasm in either OASIS study.

In a recent interview, Waljit Dhillo, a professor at Imperial College London, noted that avoiding liver monitoring would be a significant advantage for elinzanetant. He added that targeting the NK1 receptor could theoretically result in better liver safety and fewer sleep disturbances compared to Veozah, which only targets NK3. However, Dhillo emphasized that differences in liver safety might stem from the specific molecules involved rather than their receptor targets.

Bayer's R&D head Christian Rommel highlighted the robust efficacy and favorable safety profile of elinzanetant as a non-hormonal treatment for menopausal women. Bayer plans to submit the drug's data to regulatory authorities for marketing approval this year, potentially leading to a commercial clash with Astellas, which has a first-mover advantage in the market.

Bayer has not disclosed elinzanetant’s pricing until it receives FDA approval. Some analysts predict it could be as costly as or more expensive than Veozah, which currently costs at least $550 per month. Morgan Stanley analysts commented that while elinzanetant appears slightly more effective than Veozah in reducing symptom frequency over 12 weeks, this may not significantly impact business. Bayer is expected to launch elinzanetant in 2025, giving Veozah a two-year head start.