OASIS-4: Efficacy for VMS Frequency and Severity by Endocrine Therapy Type

Sleep disturbance is a distinct and clinically significant component of the vasomotor symptoms (VMS) burden that warrants dedicated assessment in patients receiving endocrine therapy for breast cancer. Carmine Valenza, MD, MPH, PhD(c), explains that nocturnal VMS can disrupt sleep in ways that may not be fully captured by daytime hot flash counts, making sleep-specific instruments an important part of comprehensive outcomes assessment. In OASIS-4, sleep quality was measured using the PROMIS Sleep Disturbance Short Form, a validated patient-reported outcome instrument with a continuous score that can be stratified into normal, mild, and moderate disturbance categories.

At baseline, patients in OASIS-4 had PROMIS sleep disturbance scores in the moderate range (approximately 60–61 on a scale where 55–60 reflects mild disturbance and 60–70 reflects moderate disturbance). By week 12, elinzanetant [Lynkuet]-treated patients demonstrated a clinically significant reduction in score, transitioning from the moderate to the normal range, while patients receiving placebo remained in the mild disturbance range. Valenza emphasizes the clinical relevance of this transition: following crossover, patients previously on placebo reached sleep quality levels equivalent to those achieved by the elinzanetant arm from the outset, and the improvements observed at week 12 were sustained throughout the 52-week study duration.

The consistency of benefit across endocrine therapy subgroups—including tamoxifen, aromatase inhibitors, and ovarian function suppression—is a particularly important finding for clinical application. According to Valenza, this consistency means that elinzanetant can be considered and discussed as a therapeutic option for virtually all patients experiencing moderate-to-severe VMS in the context of breast cancer treatment, regardless of the specific antiestrogen agent they are receiving. Given that younger patients and those on ovarian function suppression tend to experience more severe and frequent VMS, this breadth of applicability has meaningful implications for a patient population that is often underserved by available nonhormonal options.