Corbus reports 5% weight loss at 12 weeks for oral CRB-913, with full data due at ObesityWeek

On Sept. 14, 2026, Corbus Pharmaceuticals reported that CRB-913, an experimental once-daily oral obesity drug that is not a GLP-1, produced statistically significant weight loss in a Phase 1b trial, and said the full results will get a late-breaking presentation at ObesityWeek 2026, which runs Nov. 14–17 ^[1].

CANYON-1 enrolled 254 adults with obesity who did not have diabetes at 15 U.S. sites ^[1]. Everyone assigned to the drug started at 20 mg and increased the dose every two weeks; participants received placebo or 20 mg, 40 mg or 60 mg once daily for 12 weeks, then were followed for four more weeks ^[1]. CRB-913 is a peripherally restricted CB1 inverse agonist, designed to act outside the brain ^[1].

Average weight change was 0.0% on placebo, 2.8% at 20 mg, 3.3% at 40 mg and 5.0% at 60 mg, and each dose difference from placebo was statistically significant (p<0.0001) ^[1]. Weight loss had not plateaued at any dose when the 12-week treatment period ended, the company said ^[1]. Among people who completed the study in the 60 mg group, all lost some weight, 44.4% lost at least 5% of their starting weight and 6.7% lost more than 7.5%; the largest loss recorded in that group was 13.4% ^[1].

Discontinuations because of side effects ranged from 3.1% to 13.1% across the CRB-913 groups, compared with 6.9% to 20.7% reported for approved oral GLP-1 drugs and 13% to 42% for monlunabant, a different CB1 inverse agonist that was studied and then discontinued ^[1]. Psychiatric side effects were infrequent, mild to moderate and short-lived, with no serious or severe cases and no reports of suicidality; one of the 188 people who received CRB-913 had a single transient moderate depressive symptom ^[1]. Irritability was the most common and every case was mild ^[1].

Gastrointestinal side effects reported with CRB-913 were vomiting in 1.6% to 8.2%, nausea in 15.4% to 26.2%, constipation in 1.6% to 4.8% and diarrhea in 21.5% to 26.2% ^[1]. A table in the same announcement lists published rates of 31% vomiting and 47% nausea for oral semaglutide 25 mg, and 14% to 28% vomiting and 41% to 48% nausea for orforglipron ^[1]. Corbus states these are cross-trial comparisons drawn from separate studies, not head-to-head results, and that the published trials ran longer than 12 weeks ^[1].

A second experimental oral obesity drug, NA-931 from Biomed Industries, is also listed for presentation at ObesityWeek 2026 ^[2]. NA-931 is described as a quadruple receptor agonist targeting IGF-1, GLP-1, GIP and glucagon pathways ^[2]. A conference listing dated Aug. 22, 2026 says the Phase 2 study shows significant weight loss with preservation of lean mass, but no abstract was available, so the size of the effect and the number of participants have not been disclosed ^[2]. Earlier Phase 2 results reported in November 2025 showed average weight change at 13 weeks of 5.5% at 60 mg, 8.7% at 90 mg, 11.3% at 120 mg and 13.8% at 150 mg, against 1.9% on placebo, with the two highest doses statistically significant ^[2].

Why it matters for patients

People who take GLP-1 medicines for weight loss often stop. Harold Bays, M.D., an investigator on CANYON-1, said in the announcement that "a substantial number of patients with obesity either cannot tolerate GLP-1 receptor agonists or do not achieve an adequate therapeutic response," and that "more than 60% discontinue treatment within the first year" ^[1]. Both CRB-913 and NA-931 are pills, and CRB-913 works through a non-incretin mechanism, which is what makes them of interest to that group.

The context matters. The 5% average weight loss with CRB-913 at 12 weeks is smaller and measured over a shorter period than what approved drugs such as semaglutide and tirzepatide have shown in their longer pivotal trials, and the side-effect comparisons against those drugs come from separate studies ^[1]. CRB-913 is in Phase 1b testing and is not approved by the FDA, so it is not available to patients. For NA-931, how much weight was lost in the newly listed Phase 2 study, how lean mass was measured and over what period have not been reported ^[2]. Long-term safety, heart-related outcomes and whether weight loss continues past 12 weeks for CRB-913 are not yet known.

What happens next

Corbus says it plans to discuss its clinical development plan with the FDA and expects to start a Phase 2 monotherapy study of CRB-913 in the first half of 2027, and it is also evaluating combining CRB-913 with a GLP-1 ^[1]. Full CANYON-1 results are scheduled for the ObesityWeek 2026 late-breaking program Nov. 14–17 ^[1]. Biomed has said it is planning Phase 3 trials of NA-931, including a 68-week study of about 366 adults with overweight or obesity and a second study of about 360 adults, while a separate Phase 2 trial testing NA-931 with tirzepatide in 224 adults is not yet recruiting and now lists primary completion in August 2027 ^[2].