INTRODUCTION

This study evaluated the safety and tolerability of fezolinetant in women with vasomotor symptoms (VMS) due to menopause in a pooled analysis of data from three 52-week phase 3 studies (SKYLIGHT 1, 2, and 4).

METHODS

SKYLIGHT 1 and 2 were double-blind, placebo-controlled studies where women (≥ 40 to ≤ 65 years), with moderate to severe VMS (minimum average ≥ 7 hot flashes/day) were randomized to once-daily placebo, fezolinetant 30 mg or 45 mg. After 12 weeks, those on placebo were re-randomized to fezolinetant 30 mg or 45 mg, while those on fezolinetant continued on their assigned dose for 40 weeks. SKYLIGHT 4 was a placebo-controlled, double-blind, 52-week safety study. Safety was assessed by frequency of treatment-emergent adverse events (TEAEs) and endometrial events. TEAEs of special interest included liver test elevations and endometrial hyperplasia or cancer or disordered proliferative endometrium.

RESULTS

Totals of 952 participants receiving placebo, 1100 receiving fezolinetant 45 mg, and 1103 receiving fezolinetant 30 mg took ≥ 1 dose of study medication. TEAEs occurred in 55.3%, 62.9%, and 65.4%, respectively; exposure-adjusted results were consistent with these results. Most frequent TEAEs in fezolinetant-treated participants included upper respiratory tract infection (7.7-8.3%), headache (6.8-8.2%), coronavirus disease 2019 (5.8-6.1%), back pain (3.1-3.7%), arthralgia (2.9-3.2%), diarrhea (2.3-3.2%), urinary tract infection (2.9-3.4%), and insomnia (2.0-3.0%). The incidence of drug-related serious TEAEs and associated treatment withdrawals was low. Elevations in liver transaminases occurred in 1.5-2.3% of fezolinetant-treated participants, were typically asymptomatic and transient, resolved on treatment or discontinuation, with no evidence of severe drug-induced liver injury (Hy's law). Endometrial safety results were well within US Food and Drug Administration criteria. Analysis of benign and non-benign neoplasm controlled for exposure demonstrated no increased risk versus placebo.

CONCLUSION

Pooled data confirm the safety and tolerability of fezolinetant over 52 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers, NCT04003155, NCT04003142, and NCT04003389. Graphical abstract available for this article.