Q-122 as a novel, non-hormonal, oral treatment for vasomotor symptoms in women taking tamoxifen or an aromatase inhibitor after breast cancer: a phase 2, randomised, double-blind, placebo-controlled trial

Vasomotor symptoms (hot flushes and night sweats) are experienced by more than two-thirds of women with breast cancer taking oral adjuvant endocrine therapy. Safe and effective treatments are lacking. Q-122 is a novel, non-hormonal compound that has shown promise for reducing vasomotor symptoms by modulation of oestrogen-responsive neurons in the hypothalamus. We aimed to assess the efficacy and safety of Q-122 in women with breast cancer taking oral adjuvant endocrine therapy and experiencing vasomotor symptoms.We conducted a multicentre, randomised, double-blind, placebo-controlled, proof-of-concept, phase 2 trial at 18 sites in Australia, New Zealand, and the USA. Eligible participants were women, aged 18-70 years, taking a stable dose of tamoxifen or an aromatase inhibitor following breast cancer and experiencing at least 50 self-reported moderate to severe vasomotor symptoms per week. Participants were randomly assigned (1:1) using an interactive web response system to oral Q-122 100 mg or identical placebo, twice daily for 28 days. Randomisation was stratified by BMI (≤30 kg/m2 or >30 kg/m2) and use of any of a selective serotonin reuptake inhibitor, selective norepinephrine reuptake inhibitor, gabapentin, or pregabalin. Q-122 and placebo capsules were identical in appearance and containers identically labelled. During the double-blind treatment and analysis phases, the participants, investigators, clinical research organisation staff, and sponsor were masked to treatment allocation. The primary outcome was the difference in the mean percentage change from baseline in the Vasomotor Symptom Severity Score of moderate and severe hot flushes and night sweats (msVMS-SS) between Q-122 and placebo after 28 days of treatment. Primary analysis was by modified intention-to-treat and safety was assessed in all participants receiving at least one dose of study drug. This study is registered at ClinicalTrials.gov, NCT03518138.Between Oct 24, 2018, and Sept 9, 2020, 243 patients were screened, 131 of whom were randomly assigned and received treatment (Q-122 n=65 and placebo n=66). Q-122 resulted in a significantly greater mean percentage change in msVMS-SS from baseline over 28 days of treatment compared with placebo (least squares mean: Q-122 -39% [95% CI -46 to -31] vs placebo -26% [-33 to -18]; p=0·018). Treatment-emergent adverse events were generally mild to moderate and similar between the two groups (treatment-related treatment-emergent adverse events in 11 [17%] of 65 patients in the Q-122 group vs nine [14%] of 66 in the placebo group); zero patients in the Q-122 group and two (3%) patients in the placebo group had serious adverse events.Q-122 is an effective and well tolerated non-hormonal oral treatment for vasomotor symptoms in women taking oral adjuvant endocrine therapy after breast cancer. Our results support the conduct of larger and longer studies of Q-122, with potential use extending to postmenopausal women who require an alternative to menopausal hormone therapy.QUE Oncology.