Shares of Skye Bioscience (NASDAQ:SKYE) collapsed 65% on Monday after the company announced disappointing Phase 2a trial results for nimacimab, its experimental drug aimed at promoting weight loss.
The San Diego-based biotech firm reported that nimacimab monotherapy failed to achieve its primary endpoint in the CBeyond™ trial. Patients treated with the drug recorded only a 1.52% reduction in body weight, compared to 0.26% for those on placebo — a difference that was not statistically significant.
According to the company’s preliminary review, drug exposure levels were lower than expected, indicating that the 200 mg weekly subcutaneous dose may have been too low to show meaningful efficacy as a standalone treatment. Skye said this outcome could justify testing higher doses in future studies.
Despite the setback for nimacimab alone, Skye Bioscience highlighted encouraging data from the combination arm of the study. Participants who received nimacimab plus semaglutide (Wegovy) achieved 13.2% weight loss, compared to 10.25% for those treated with semaglutide alone — a difference deemed statistically significant.
The company also underscored nimacimab’s strong safety profile, noting that there was no increase in gastrointestinal side effects when used alongside semaglutide and no neuropsychiatric issues reported. This, the firm said, could distinguish nimacimab from earlier CB1 inhibitors that were withdrawn over psychiatric safety concerns.
Skye said it is still analyzing the full dataset and assessing next steps, including a possible follow-up Phase 2 study. The company plans to release additional results from the ongoing 26-week extension study during the first quarter of 2026.
The failure of the monotherapy trial marks a major blow for Skye’s obesity program, which had positioned nimacimab as a novel CB1-targeting therapy that could address weight loss without the central nervous system side effects seen in past treatments.
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