AbCellera ABCL-635 Cuts Menopause Hot Flashes 83% in Phase II Trial, Stock Surges 25%

AbCellera Biologics reported positive top-line four-week results from a Phase II trial of ABCL-635, a potential first-in-class once-monthly injectable antibody targeting the neurokinin 3 receptor for moderate-to-severe vasomotor symptoms associated with menopause. The randomized, double-blind, placebo-controlled study enrolled 92 postmenopausal women, exceeding the planned 80 participants, each receiving a single 600-milligram subcutaneous dose of ABCL-635 or placebo. At four weeks, ABCL-635 reduced moderate-to-severe hot flash frequency by 83% from baseline, versus 33% for placebo, with patients on the drug recording a mean reduction of 8.8 events per day compared with 3.5 for placebo, a placebo-adjusted difference of 5.3 fewer events per day.

The drug also improved symptom severity, sleep disturbance and patient-reported outcomes. No serious or severe adverse events were reported in the treatment group, though headaches, fatigue and one mild, resolved transaminase elevation were noted. Benzinga described the results as setting a new efficacy benchmark in the space.

The stock surged roughly 25% in premarket trading on August 10 and hit a 52-week high of 8.79 USD intraday. AbCellera is following participants for 12 weeks total to gather additional safety, pharmacokinetic and exposure-response data.