OASIS-4 in Focus: Lead Investigator Reviews Trial Design
A panelist highlights that at ASCO 2025, a landmark phase 3 trial showed a new treatment significantly reduced moderate-to-severe hot flashes in patients with breast cancer receiving endocrine therapy, with rapid and sustained symptom relief and high patient continuation rates over 2 years.
At the ASCO 2025 meeting, the primary results of a major phase 3 randomized, placebo-controlled trial were presented, focusing on women with breast cancer or at high risk of developing it who are undergoing endocrine therapy. This study was the first to specifically assess the control of vasomotor symptoms in this patient population. Unlike previous trials that studied women experiencing natural or surgically induced menopause, this trial enrolled over 700 participants who reported at least 35 moderate-to-severe hot flashes per week, which significantly impacted their daily and social activities as well as sleep.
Participants were randomly assigned in a 2:1 ratio to receive either the study drug or a placebo for the first 12 weeks. After this period, those taking placebo switched to the active treatment, and both groups continued the drug for an additional 40 weeks. The trial also offered an optional 2-year extension phase for patients wishing to continue treatment. The primary goal was to reduce the frequency of moderate-to-severe hot flashes from baseline to week 12, with additional measures assessing symptom severity and early response at weeks 1 and 4, as well as sustained effectiveness throughout the study.
Results showed a significant reduction in hot flash frequency as early as the first week of treatment, with a mean decrease of 3.5 episodes per day at week 12, which was maintained through week 52. Patients who initially received placebo experienced a similar improvement after switching to the active treatment. Importantly, over 90% of participants chose to continue therapy during the 2-year extension, highlighting the drug’s efficacy and tolerability in managing these challenging symptoms for patients with breast cancer receiving endocrine therapy.
Newsletter
Get the latest clinical updates, case studies, and expert commentary in obstetric and gynecologic care. Sign up now to stay informed.
