Skye Bioscience Inc. (SKYE) released interim data Monday from its CBeyond Phase 2a study that should make obesity drugmakers take notice. The company's experimental antibody nimacimab, when combined with Novo Nordisk's (NVO) semaglutide (better known as Wegovy), produced over 22% weight loss after a full year of treatment. More intriguingly, patients who stopped taking the combo regained far less weight than those on semaglutide alone.
Here's what makes this interesting: weight regain after stopping GLP-1 drugs like Wegovy has become one of the category's biggest challenges. Skye's data suggests nimacimab might help solve that problem.
The Numbers Behind the Weight Loss
The study tracked patients through 52 weeks of treatment in the extension phase of Skye's CBeyond proof-of-concept trial. Nimacimab is what scientists call a negative allosteric modulating antibody that peripherally inhibits CB1 receptors, which play a role in metabolism and appetite regulation.
Out of 10 participants who started the nimacimab plus semaglutide combination, seven completed the full year. These patients showed 14.4% mean weight loss at 26 weeks, then continued losing weight through week 52, shedding an additional 7.9%. That brought total weight loss to 22.3% with no plateau in sight.
The comparison arm tells an equally important story. Nine participants started on placebo plus semaglutide, and seven finished the full course. This group achieved 13.9% weight loss at 26 weeks, adding another 5.8% during the extension period for a total of 19.7% at 52 weeks. So the nimacimab combination produced an extra 2.6 percentage points of weight loss over a full year.
Safety looked clean throughout the extension period. No serious adverse events or adverse events of special interest emerged, and the combination was well-tolerated at the doses tested.
The Weight Regain Story
This is where things get more compelling. Participants on nimacimab plus semaglutide who entered the 13-week off-therapy follow-up regained only 17.8% of the weight they'd lost at 26 weeks. That represents more than 50% mitigation of weight rebound compared to what typically happens when patients stop GLP-1 therapy.
By contrast, patients treated with semaglutide alone regained 37.3% of their lost weight during the same off-therapy period. If these results hold up in larger studies, they suggest nimacimab might provide some durability even after patients stop treatment.
Context and Caveats
Keep in mind we're talking about small patient numbers here. Seven completers in each arm isn't enough to draw definitive conclusions, but it's enough to warrant attention and further study.
Skye previously reported in October 2025 that at 26 weeks, the combination achieved 13.2% weight loss versus 10.25% for semaglutide alone. The gap has widened over time, which suggests the combination effect compounds with longer treatment duration.
There's also a cautionary note: nimacimab flopped as monotherapy. The standalone drug produced just 1.52% weight loss versus 0.26% for placebo, missing its primary endpoint. So nimacimab isn't replacing GLP-1 drugs anytime soon. Its value, if any, lies in boosting what drugs like Wegovy and Eli Lilly's (LLY) Ozempic already accomplish.
Speaking of Lilly, Skye reported positive preclinical data in September 2025 testing nimacimab alongside tirzepatide, Lilly's dual GIP/GLP-1 agonist. The company appears to be positioning nimacimab as a potential add-on across the GLP-1 category.
What Analysts Are Saying
William Blair noted that with cash runway extending into the fourth quarter of 2026, a more thorough analysis of the Phase 2a CBeyond study could attract investor interest, assuming the data supports a relationship between drug exposure and weight loss.
Skye expects to release topline data from the full CBeyond Phase 2a extension, including monotherapy results and complete 13-week off-therapy follow-up data, in the third quarter of 2026.
SKYE Price Action: Skye Bioscience (SKYE) shares were down 5.53% at $0.95 at publication time Monday.
