Corbus expects topline Phase 1b results for its peripheral CB1 drug CRB-913

Corbus Pharmaceuticals says its 240-participant Phase 1b trial of CRB-913, called CANYON-1, finished its last patient visit in August 2026, with topline results expected in September 2026. The drug is a peripherally restricted CB1 receptor antagonist being developed for obesity, part of a much larger wave of experimental weight-loss mechanisms now in testing.

CRB-913 is one entry in a fast-growing obesity pipeline. An industry tracker following drug development in this space counts more than 150 active obesity and weight-related programs running from early discovery through Phase 3, spanning GLP-1 drugs, amylin agonists, RNAi therapies and CB1-targeted compounds ^[1]. That tracker specifically lists CB1 antagonists among the non-GLP-1 mechanisms companies are pursuing as they look for options beyond the incretin drugs that now dominate the market ^[1].

The broader pipeline picture helps explain why a CB1 readout matters even though it is much earlier-stage than the drugs getting headlines this year. Retatrutide, a three-hormone injectable from Eli Lilly, produced 28.3% average weight loss at 80 weeks in its Phase 3 trial, and Lilly plans to file for FDA approval in early 2027 ^[1]. Oral options have also multiplied: an oral form of Wegovy was approved in December 2025 with 16.6% average weight loss in its pivotal trial, and Lilly's Foundayo (orforglipron) was approved in April 2026 after producing 12.4% average weight loss at 72 weeks ^[1]. Those approved and late-stage drugs still largely rely on GLP-1 receptor signaling, which is tied to common side effects like nausea and vomiting ^[1].

CB1 blockers work through a different pathway entirely, targeting cannabinoid receptors rather than gut hormone receptors. The available reporting on the current obesity pipeline does not include specific details about CRB-913's dosing, trial design, or Corbus's own description of why a "peripheral" CB1 approach might avoid past problems with this drug class; those specifics are not yet known from the sources reviewed for this story.

Why it matters for patients

Most of today's approved and late-stage obesity drugs, including Wegovy, Zepbound, Foundayo, and retatrutide, work by activating GLP-1 or related gut hormone receptors ^[1]. That shared mechanism means patients who cannot tolerate one GLP-1 drug's gastrointestinal side effects may run into similar problems with others in that class, even oral versions ^[1]. A pipeline that includes non-GLP-1 mechanisms, such as amylin-based drugs like petrelintide, RNAi therapies targeting fat and muscle signaling, and CB1 antagonists, is significant because a mechanism failure or side-effect problem with one pathway would not necessarily rule out treatment options from a completely different one ^[1].

For patients specifically curious about CB1, the practical bottom line is that this is still an early-stage program. A Phase 1b study of 240 participants is designed mainly to test safety, tolerability and early signals of effect, not to establish how well a drug works compared with approved treatments. Nothing in the current reporting indicates CRB-913 is close to a Phase 3 trial, FDA submission, or approval timeline, and it is not part of the roster of drugs already reshaping obesity treatment access and pricing this year ^[1].

What happens next

Corbus expects topline CANYON-1 results in September 2026, following the trial's final patient visit in August 2026. What those results will show, and what they mean for CRB-913's path toward later-stage testing, is not yet known.