Corbus reports 5% mean weight loss at 12 weeks with oral CRB‑913, before peer review

Corbus Pharmaceuticals says its experimental oral obesity drug CRB-913 produced 5.0% mean weight loss after 12 weeks at the highest tested dose. The result comes from company-reported topline data, not a peer-reviewed paper, and the drug is still in early clinical development.

CRB-913 is a CB1 inverse agonist designed to act mainly outside the brain. Corbus is testing whether limiting exposure in the brain can reduce psychiatric effects associated with drugs in this class while preserving a useful metabolic effect. The 12-week study cannot settle that safety question.

The highest dose produced 5.0% mean weight loss at 12 weeks

CANYON-1 enrolled 254 adults with obesity who did not have diabetes at 15 sites in the United States. Participants were randomly assigned to placebo or to daily CRB-913 at target doses of 20, 40, or 60 milligrams. Everyone assigned to the medicine started at 20 milligrams, with higher-dose groups increasing every two weeks. Treatment lasted 12 weeks, followed by four weeks of observation.

Corbus reported no mean weight change in the 66-person placebo group. The least-squares mean changes were 2.8% at 20 milligrams, 3.3% at 40 milligrams, and 5.0% at 60 milligrams. Each comparison with placebo had a reported p value below 0.0001. A p value describes how compatible the result is with chance under the study's assumptions. It does not measure how useful the drug will be in routine care.

Among participants who completed treatment at 60 milligrams, 44.4% lost at least 5% of their starting weight and 6.7% lost more than 7.5%. Corbus said average weight loss had not reached a plateau by week 12. That does not show how much additional weight people might lose, or whether they would maintain it.

Safety comparisons with GLP-1 drugs are not head-to-head evidence

Corbus reported no serious or severe psychiatric adverse events and no suicidality. One of 188 participants who received CRB-913 had a moderate, temporary depressive symptom. Irritability was the most common psychiatric event, and the company described every case as mild.

Digestive side effects at 60 milligrams included nausea in 22.6%, diarrhea in 22.6%, vomiting in 1.6%, and constipation in 4.8%. The company compared those rates with results from separate studies of oral semaglutide and orforglipron. Those studies used different patients and lasted much longer, so the comparison cannot show that CRB-913 is safer or easier to tolerate.

The finding is an early signal, not evidence for clinical use

This was a Phase 1b trial designed to help select doses and look for early safety and efficacy signals. Twelve weeks is too short to establish durable weight loss, uncommon harms, or long-term psychiatric safety. The detailed dataset has not yet been presented at a scientific meeting or published in a journal.

Corbus says it plans to present fuller results at ObesityWeek in November 2026 and discuss the development plan with the FDA. A Phase 2 monotherapy study is expected in the first half of 2027. CRB-913 is investigational and is not approved for obesity treatment.