Monlunabant
Monlunabant (INV-202)
Also known as: INV-202
Novo Nordisk's oral peripherally acting CB1 blocker: 7.1 kg weight loss in 16 weeks in Phase 2a, but with dose-related anxiety, irritability and sleep problems that Phase 2b must resolve.
Overview
Monlunabant is an oral CB1 inverse agonist designed to act mainly outside the brain. A 243-person Phase 2a published in The Lancet Diabetes and Endocrinology reported 7.1 kg loss on 10 mg versus 0.7 kg on placebo over 16 weeks. Neuropsychiatric side effects rose with dose, the same problem that removed rimonabant from the market, and Novo launched a Phase 2b in 2025 to find a dose that separates benefit from harm.
Mechanism of action
Inverse agonism of peripheral cannabinoid CB1 receptors, reducing fat storage and improving metabolic signaling.
Key studies & citations
- Human2025
Monlunabant, a peripherally acting CB1 inverse agonist, in obesity: Phase 2a
7.1 kg loss at 16 weeks on 10 mg; dose-dependent neuropsychiatric effects.
The Lancet Diabetes and Endocrinology - Human2024
Novo Nordisk Phase 2a results for monlunabant
Company moved to Phase 2b to define dose and safety.
Novo Nordisk press release
Frequently asked questions
Why is monlunabant a safety story?
The drug is meant to stay out of the brain, yet anxiety, irritability and sleep disturbance increased with dose in Phase 2a. Whether a lower dose keeps the weight loss without those effects is the open question.