Corbus Pharma (CRBP) Stock Drops 60% After Novo Nordisk's Cannabinoid-Based Weight Loss Drug Trial Disappoints

Shares of Corbus Pharmaceuticals CRBP experienced a severe drop on Friday, plummeting almost 60% from $52 to $21, as competitor Novo Nordisk NVO published trial results for monlunabant, a cannabinoid receptor 1 (CB1) inverse agonist. Novo Nordisk shares also traded down roughly 5.5%

Both companies are developing drugs that target the CB1 receptor, a critical part of the endocannabinoid system, which regulates appetite and metabolism. Corbus's experimental drug, CRB-913, belongs to the same class as monlunabant.

Despite Novo Nordisk's announcement of results on weight-loss outcomes, investors appear to be concerned about the actual outcome of the trials.

Monlunabant, the drug tested by Novo Nordisk, acts on the same receptors as cannabis-related compounds.

It is a synthetic small molecule designed to block the CB1 receptor, which plays a key role in appetite regulation. The endocannabinoid system, which is naturally activated by cannabinoids from the cannabis plant, like THC, is the biological target of both Novo's monlunabant and Corbus's CRB-913.

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Bearish Reactions To Novo Nordisk's Trial Data

Novo Nordisk’s trial showed that monlunabant resulted in significant weight loss for participants, with those on a 10 mg dose losing an average of 7.1 kg compared to only 0.7 kg in the placebo group.

However, the market's reaction was negative. Probable reasons for such market reactions are linked to:

• Safety Concerns: While the trial showed significant weight loss, the adverse events, particularly neuropsychiatric side effects like anxiety, irritability and sleep disturbances, were dose-dependent and more frequent at higher doses. These side effects, even though mild to moderate, could raise concerns about the drug’s long-term safety and commercial viability, especially in the competitive obesity drug market​.
• Limited Additional Benefits at Higher Doses: The trial indicated that limited additional weight loss was seen at higher doses of monlunabant, which might signal diminishing returns for increased dosages. This could raise questions about the drug’s scalability and effectiveness at higher or sustained dosages, casting doubt on its ability to compete with other obesity treatments that offer clearer dose-response benefits​.
• Investor Expectations: Given Novo Nordisk's strong position in the obesity treatment market (notably with its blockbuster drug Wegovy), expectations for new pipeline drugs like monlunabant may have been exceedingly high.
• Competition and Future Trials: While Novo has committed to advancing monlunabant into a larger phase 2b trial in 2025, this indicates that more work is needed to refine dosing and better understand the safety profile. The need for further trials may prolong investor uncertainty, particularly when competitors (like Corbus Pharmaceuticals) are also developing drugs targeting the same CB1 receptor pathway​

What This Means for Corbus Pharmaceuticals

For Corbus Pharmaceuticals, Novo Nordisk's struggles present an even greater challenge.

As CRB-913 is also a CB1 inverse agonist, the setbacks Novo faced may have deepened concerns about whether Corbus can develop a commercially viable product.

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Cover: Benzinga Pro