Skye Bioscience has released compelling preclinical data demonstrating nimacimab's potential as a differentiated obesity treatment, showing superior weight loss durability and enhanced combination efficacy compared to incretin therapies as the company approaches its Phase 2a data readout.
The biotechnology company reported that nimacimab, a negative allosteric modulating antibody targeting peripheral CB1 receptors, maintained weight loss for approximately 20 days after treatment cessation in preclinical diet-induced obesity mouse models, with only 7.4% weight regain by day 24. In contrast, mice treated with low-dose tirzepatide regained 29.7% of their weight within the same timeframe, highlighting a significant durability advantage.
Combination Strategy Shows Enhanced Efficacy
The preclinical studies revealed that combining nimacimab with suboptimal tirzepatide doses (3nmol/kg daily) achieved 44% vehicle-adjusted weight loss at day 25, surpassing both monotherapy treatments and even optimal tirzepatide dosing. The combination outperformed nimacimab alone (21.5% vehicle-adjusted weight loss) and suboptimal tirzepatide monotherapy (29.7% vehicle-adjusted weight loss), while also exceeding optimal tirzepatide dosing at 10 nmol/kg (38.9% vehicle-adjusted weight loss).
"This highlights a meaningful opportunity to develop combination strategies that achieve greater efficacy at lower doses, potentially improving tolerability, reducing cost, and expanding treatment accessibility," the company stated in its financial report.
Addressing Weight Rebound Challenges
The preclinical data addressed a critical limitation of current obesity treatments - weight regain after therapy discontinuation. When nimacimab was used as maintenance therapy following initial tirzepatide treatment, it significantly reduced rebound weight gain from 29.7% to 12.8%, positioning it as a potential post-incretin maintenance therapy.
"This 'rebound effect' has been well-documented in animal models and clinical data and represents a major issue for patients who come off incretin-based therapies," according to the company's research findings.
Phase 2a Trial Progress and Timeline
Skye's CBeyond Phase 2a obesity trial continues to progress with patients receiving active treatment through scheduled follow-ups. The independent Data Safety Monitoring Committee has completed four unblinded reviews without raising concerns, allowing the study to continue per protocol.
Patient enrollment for the 26-week extension study began in July 2025, with both combination and monotherapy arms expected to enroll approximately 50% of patients from the original study. This extension could provide up to 52-week safety and efficacy data by 2026.
President and CEO Punit Dhillon emphasized the clinical significance: "We believe nimacimab's peripherally-restricted CB1 mechanism represents a fundamentally different approach, one that could offer real-world advantages as a monotherapy or in combination, without compounding gastrointestinal side effects."
Mechanism of Action Advantages
The preclinical studies highlighted nimacimab's unique binding mechanism as an allosteric inhibitor, which occurs independently of endogenous CB1 ligand engagement. This distinguishes it from small molecule CB1 inhibitors that must compete for binding at the orthosteric site, potentially providing enhanced potency and therapeutic window in obesity patients who often have elevated endocannabinoid levels.
The research demonstrated that nimacimab regulates key metabolic hormones, including increasing GLP-1, decreasing leptin and resistin, and reducing caloric intake by engaging peripheral tissues that restore central hormone signaling for appetite and satiety control.
Broader Metabolic Benefits
Beyond weight loss, the preclinical data showed nimacimab improved glycemic control through reduced fasting glucose and insulin levels, along with significant blood glucose reduction in glucose tolerance tests. The treatment also modulated lipid metabolism, reducing serum cholesterol, steatosis, and obesity-induced inflammation and liver fibrosis.
Financial Position and Manufacturing Progress
Skye reported $48.6 million in cash, cash equivalents, and short-term investments as of June 30, 2025, with projected funding through at least Q1 2027. The company successfully manufactured and released its first batch of drug product for Phase 2a resupply and initiated a formulation development collaboration with Arecor Therapeutics to develop higher concentration formulations.
Research and development expenses increased to $14.3 million in Q2 2025 from $4.1 million in the same period of 2024, primarily due to contract manufacturing and clinical trial costs. Net loss totaled $17.6 million for the quarter.
The company plans to host a key opinion leader event webcast from Nasdaq on September 4, 2025, to discuss perspectives regarding the anticipated Phase 2a top-line data readout scheduled for late Q3/early Q4 2025.
