ABCL Soars 35% on ABCL635 Phase 2 Hot Flash Data

AbCellera (ABCL) reported positive Phase 2 data for ABCL635 this morning, and the stock ripped 34.8% to $9.34. It closed Friday at $6.93. The market cap now sits at roughly $2.12 billion on volume of 46 million shares, more than 10x the daily average. Investors are betting that an antibody injected once a month can beat a daily pill.

The Phase 2 enrolled 92 postmenopausal women averaging about 10 moderate-to-severe hot flashes per day. A single subcutaneous 600 mg dose of ABCL635 cut daily VMS frequency by 83% from baseline at week 4, versus 33% for placebo, a 50% placebo-adjusted difference. Severity dropped 58% versus 12% for placebo, a 46% adjusted difference. Both endpoints hit statistical significance (p<0.001) by week 1 and held through week 4. Sleep scores and patient global impression of change also improved meaningfully. No serious adverse events, no severe AEs, and no discontinuations.

ABCL635 targets the neurokinin 3 receptor (NK3R) on KNDy neurons in the hypothalamus, the same mechanism that Astellas validated with Veozah (fezolinetant), FDA-approved in May 2023. But ABCL635 is an antibody, not a small molecule. That means monthly subcutaneous dosing instead of a daily pill, and a cleaner safety profile. Fezolinetant carries a liver safety warning; the FDA required baseline and monthly liver function monitoring before starting treatment. Bayer’s elinzanetant, another oral NK3R antagonist, is under FDA review and faces the same class scrutiny. ABCL635 showed no liver signals in this 92-patient Phase 2 readout.

The market opportunity is not subtle. Roughly 12 million US women experience moderate-to-severe vasomotor symptoms. Many cannot or will not take hormone therapy. Veozah generated $97 million in its first full year on the US market, a modest launch partly constrained by the liver monitoring requirement. A well-tolerated monthly injection without hepatic safety baggage could expand the addressable population meaningfully.

The risks are standard for a Phase 2 asset. The durability question, whether a single dose lasts a full month or a Phase 3 maintenance schedule requires more frequent dosing, won’t be answered until the Phase 2b/3 dose-ranging trial reads out. Immunogenicity is always a watch item with therapeutic antibodies. And Bayer’s elinzanetant, if approved, will be the second oral NK3R antagonist on the market before ABCL635 reaches registration.

AbCellera plans a Phase 2b/3 dose-ranging study next. The timeline and design were not in the morning press release, but the company hosts a conference call at 7:30 AM ET today. For a framework on parsing these readouts, see the guide to reading clinical trial press releases.

Source: AbCellera press release, August 10, 2026 · ABCL635 Phase 2 on ClinicalTrials.gov (NCT07118891)