Novo’s Next-Gen CB1 Drug Leads to Weight Loss in Phase II, but Neuropsychiatric Events Reported

A woman's hand holding a scale.

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Novo Nodrisk’s cannabinoid receptor–targeting obesity pill was picked up in the $1.1 billion acquisition of Inversago Pharmaceuticals last year.

Novo Nordisk’s $1.1 billion acquisition of Inversago Pharmaceuticals last year is paying off with Phase IIa results for an oral therapy picked up in the deal. Monlunabant, a small molecule oral cannabinoid receptor 1 (CB1) inverse agonist, has cut weight by 15 lbs after 16 weeks of treatment, compared to just 1.5 lbs for placebo, according to a Friday press release.

The data add to the deluge of readouts on obesity pills this month, following data from Roche and Terns Pharmaceuticals, as well as from Novo’s amycretin. All three of those drugs are GLP-1 agonists, however, where as monlunabant targets the endocannabinoid system.

The trial examined three doses of monlunabant in 243 patients, and the average weight loss of 15 lbs was achieved in the lowest dose arm, where patients received 10 mg. Novo said that “limited additional weight loss was seen at higher doses of monlunabant.” Novo did not report weight loss as a percentage of body weight as is often done in weight loss trials.

As for safety, Novo recorded mostly mild to moderate gastrointestinal adverse events but also said there were reports of “mild to moderate neuropsychiatric side effects,” such as anxiety, irritability and sleep disturbances. These events were more frequent in patients taking the study drug compared to placebo and were dose dependent. There were no serious adverse events reported from these neuropsychiatric side effects, Novo said.

Graig Suvannevejh, senior biopharmaceuticals and biotechnology equity research analyst at Mizuho Americas, told BioSpace in August that there have been safety concerns about this class in the past, specifically around the risk of suicidality. Novo’s billion-dollar bet on the space was seen as validation that the next generation of CB1 receptor therapies have overcome the issues.

Martin Holst Lange, executive vice president and head of development at Novo, said in a statement that the company needs to learn more about optimal dosing to balance safety and efficacy, but the results point to the weight loss potential of monlunabant.

Novo plans to initiate a bigger Phase IIb trial to further explore dosing and the safety profile of monlunabant. The trial is expected to get underway next year.

Results from the Phase IIa were eagerly awaited by analysts, who said Novo’s success here could mean big things for two smaller biotechs also working on drugs for the CB1 receptor, Corbus Pharmaceuticals and Skye Bioscience.

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