Skye Bioscience has announced promising new preclinical data for nimacimab, its novel peripherally-restricted CB1 antibody, demonstrating significant weight loss potential both as monotherapy and in combination with established GLP-1 receptor agonists.
In a murine diet-induced obesity (DIO) model, the combination of nimacimab with tirzepatide achieved over 30% weight loss after 25 days of treatment. As monotherapy, nimacimab produced 23.5% weight loss, comparable to results seen with both tirzepatide and monlunabant when administered individually.
"This new preclinical study highlights that a truly peripherally-restricted CB1 inhibitor—nimacimab—effectively drives weight loss in a DIO model," said Punit Dhillon, CEO of Skye Bioscience. "Nimacimab compared favorably to and provided significant additive weight loss when combined with GLP-1-targeted drugs like tirzepatide."
The study builds on previous preclinical research in human CB1 knock-in mice that demonstrated dose-dependent weight loss. Biomarker analyses indicated that nimacimab-driven weight loss was associated with beneficial changes in key hormones, glycemic control, and inflammatory markers.
Differentiated Mechanism of Action
Beyond weight loss efficacy, Skye released new in vitro data characterizing nimacimab's unique mechanism of action. The studies demonstrated that nimacimab's non-competitive allosteric binding to CB1 provides a potentially advantageous mechanism compared to small molecule inhibitors like monlunabant.
When tested against varying concentrations of the CB1 agonist CP55940, nimacimab maintained consistent potency even at high agonist concentrations (2000nM), while monlunabant's effectiveness declined significantly under the same conditions.
Dr. Chris Twitty, Chief Scientific Officer at Skye, explained the significance: "These data demonstrate for the first time how nimacimab's allosteric binding to the CB1 receptor is differentiated from small molecules which bind to the receptor's active orthosteric site. We know that in disease states such as obesity, the CB1 receptor and its natural ligands are upregulated."
"When there is significant competition for CB1 binding, the activity of small molecules like monlunabant can be significantly impacted," Twitty continued. "Clinically this could result in impacting the relationship between pharmacodynamics and pharmacokinetics of the drug, ultimately requiring more of the small molecule to overcome the competition."
Potential Safety Advantages
A key advantage of nimacimab's approach is its peripheral restriction, designed to avoid the central nervous system effects that derailed earlier CB1 inhibitors. Previous small molecule CB1 inhibitors showed promising weight loss results but were discontinued due to neuropsychiatric side effects resulting from brain penetration.
"In the context of CB1 inhibition, we aim to realize the weight loss and metabolic benefits of this mechanism without the neuropsychiatric side effects seen with small molecule drugs," noted Twitty. "The potential superior potency of nimacimab in this disease state may offer the widest possible therapeutic window among CB1 inhibitors."
Clinical Development Timeline
Skye is currently conducting a Phase 2a clinical trial (ClinicalTrials.gov: NCT06577090) evaluating nimacimab in obesity. The study, known as CBeyond™, is also assessing the combination of nimacimab with the GLP-1R agonist semaglutide (Wegovy®).
Initial data from this Phase 2a study is expected in late Q3 or early Q4 of 2025, which will provide important insights into whether the impressive preclinical results translate to human subjects.
Market Context
The obesity treatment landscape has been transformed by GLP-1 receptor agonists like Eli Lilly's tirzepatide (Mounjaro/Zepbound) and Novo Nordisk's semaglutide (Wegovy). However, there remains significant interest in complementary mechanisms that could enhance weight loss, improve tolerability, or address non-responders.
CB1 inhibition represents a mechanistically distinct approach to weight management that could potentially complement the effects of GLP-1 targeted therapies. The preclinical data suggesting additive effects when combining nimacimab with tirzepatide supports this hypothesis.
Skye Bioscience's stock responded positively to the announcement, with trading volume significantly above average following the data release.
Future Directions
If clinical trials confirm the preclinical findings, nimacimab could potentially address several unmet needs in obesity treatment. The company believes the drug shows promise both as monotherapy and in combination with GLP-1 targeted drugs.
"Skye believes nimacimab shows potential both as a monotherapy and in combination with a GLP-1 targeted drug to address unmet needs in obesity with the potential to change weight loss standards of care," Dhillon stated.
The development of nimacimab represents part of a broader industry trend toward combination approaches for obesity, with multiple mechanisms being explored to maximize efficacy while maintaining acceptable safety profiles.
