Skye Bioscience's Investigational Drug Disappoints As Monotherapy For Weight Loss

Skye Bioscience (NASDAQ:SKYE) shares plummeted 60% after its nimacimab monotherapy failed to achieve the primary weight loss endpoint in a Phase 2a study, with preliminary analysis suggesting insufficient drug exposure. Despite this, the combination of nimacimab with semaglutide demonstrated a statistically significant and clinically meaningful improvement in weight loss (-13.2% vs. -10.25%) compared to semaglutide alone, alongside a favorable safety profile, indicating potential for further development in combination therapies despite the negative market reaction to the monotherapy results.

Analysis

Skye Bioscience Inc. (NASDAQ:SKYE) stock sank on Monday after the company released topline data from its 26-week Phase 2a CBeyond proof-of-concept study of nimacimab. The nimacimab monotherapy arm did not achieve the primary endpoint of weight loss compared to placebo (-1.52% vs. -0.26 for placebo, mITT). Preliminary pharmacokinetic analysis showed lower than expected drug exposure of nimacimab, supporting evaluation of higher dosing. Also Read: Skye Bioscience Advances Position In Competitive Obesity Market With Promising Data In the combination cohort, nimacimab 200 mg plus semaglutide demonstrated a clinically meaningful magnitude of weight loss compared to semaglutide alone (-13.2% vs -10.25%, p=0.0372, mITT), with no plateau being observed through Week 26. This finding supports potential further studies to evaluate combinations of nimacimab and incretin-based therapies. Semaglutide is an active ingredient in Novo Nordisk A/S’ (NYSE:NVO) Wegovy and Ozempic. At the tested dose and exposure levels, nimacimab 200 mg demonstrated a favorable safety profile with placebo-like tolerability. Combined with semaglutide, there was no increase in gastrointestinal (GI) adverse events. There were no increases in neuropsychiatric adverse events reported resulting from treatment with nimacimab. Skye Combination Promise In the per-protocol analysis, 100% of the patients in the combination arm achieved >5% weight loss (vs. 85% with semaglutide), and 67% achieved >10% weight loss (vs. 50% with semaglutide). An improvement in the lean mass to fat ratio was observed at Week 26, comparing the nimacimab plus semaglutide combination arm to the placebo arm (0.26 vs. 0.02), and the combination arm compared to semaglutide alone (0.26 vs. 0.13). Nimacimab 200 mg demonstrated a clean safety profile as a monotherapy with placebo-like tolerability. No increase in GI adverse events was observed when combined with semaglutide. In the safety analysis population, rates of GI adverse events were 27% with nimacimab alone versus 29.5% with placebo, and 57.1% in combination with semaglutide versus 66.7% with semaglutide alone. No neuropsychiatric concerns were observed. Also, nimacimab 200 mg (as a monotherapy or in combination with semaglutide) did not increase anxiety, insomnia, or depression. The CBeyond study had an overall discontinuation rate of 27%. Discontinuations across the study were attributed to adverse events, with the placebo group contributing 60% of these discontinuations. Price Action: SKYE stock is down 60% at $1.90 during the premarket session at the last check on Monday. Read Next: Image: Shutterstock © 2025 Benzinga.com. Benzinga does not provide investment advice. All rights reserved. Skye Bioscience's stock collapsed 60% following the announcement that its Phase 2a study of nimacimab as a monotherapy failed to meet its primary weight loss endpoint, delivering only a -1.52% reduction compared to -0.26% for placebo. The company noted that lower-than-expected drug exposure may have been a factor, suggesting potential for higher dosing in future studies. Despite this headline failure, the data revealed a compelling alternative path for the drug. In a combination cohort, nimacimab with semaglutide (the active ingredient in NVO's Wegovy) demonstrated a statistically significant (p=0.0372) and clinically meaningful improvement in weight loss versus semaglutide alone (-13.2% vs. -10.25%). This combination also resulted in a higher percentage of patients achieving >10% weight loss (67% vs. 50%) and showed no plateau in effect at 26 weeks. Critically, nimacimab exhibited a favorable safety profile with placebo-like tolerability and did not exacerbate the gastrointestinal side effects of semaglutide, with GI adverse event rates in the combo arm being lower than with semaglutide alone (57.1% vs. 66.7%). The lack of any reported neuropsychiatric side effects and an observed improvement in the lean mass to fat ratio further position nimacimab as a potentially valuable synergistic agent in the obesity market, even as its viability as a standalone treatment is now in question.

Key Decisions for Investors

• Recognize that the 60% stock collapse has reset valuation based on the monotherapy's failure, shifting the entire investment thesis to the higher-risk, but potentially valuable, combination therapy pathway.
• For risk-tolerant investors, the market's severe punishment for the monotherapy miss may present a speculative opportunity, as the positive combination data with semaglutide and the strong safety profile appear to have been largely overlooked.
• Upcoming corporate guidance on a revised dosing strategy and the design of a pivotal combination trial will be the most critical catalysts for any potential recovery in the stock.
• Monitor the company's emphasis on differentiated benefits, such as the preservation of lean muscle mass and the absence of increased GI or neuropsychiatric side effects, as these are key to securing a competitive position in the crowded obesity market.