Data on Novo Nordisk experimental weight-loss drug show mostly mild side effects

By Deena Beasley

(Reuters) -Novo Nordisk on Sunday said full results from two late-stage trials of its experimental weight-loss drug CagriSema show that side effects were mainly mild-to-moderate and other outcome results, including blood sugar levels, were positive.

The company had previously announced top-line results for the 68-week studies, which found that CagriSema led to nearly 23% weight loss for overweight or obese adults, while overweight type 2 diabetics lost nearly 16% of their weight. Those results, however, disappointed investors, sending Novo's shares lower. The company last month ousted its CEO Lars Fruergaard Jorgensen.

The full Phase 3 results were presented in Chicago at the annual meeting of the American Diabetes Association and published in the New England Journal of Medicine.

In the obesity trial, 79.6% of CagriSema patients had mainly transient, mild-to-moderate gastrointestinal effects such as nausea, vomiting and constipation, compared with 39.9% of placebo patients. Serious adverse events occurred in 9.8% of CagriSema patients and 6.1% of placebo patients.

In the CagriSema group, 6% of patients dropped out of the trial due to adverse events, compared with 3.7% in the placebo group.

"Everything was in line with what we expected," Dr. Melanie Davies, lead investigator of the CagriSema diabetes trial, and co-director of the Leicester Diabetes Centre, told Reuters.

The percentage of patients who had a glycated hemoglobin, or blood sugar, level of 6.5% or less was 73.5% in the CagriSema group and 15.9% in the placebo group.

Dr. Davies acknowledged questions about why many patients in the trials were not given the highest tested dose. "Those patients on lower doses actually had higher weight loss reduction," she said. "We've not really seen that before because we have not had powerful treatments that have got people close to target."

CagriSema is a weekly injection that combines Novo's blockbuster GLP-1 drug Wegovy with another molecule, cagrilintide, that mimics a hunger-suppressing pancreatic hormone called amylin.

The CagriSema Phase 3 trial results "compared very favorably also with what we've seen with tirzepatide, which was previously the best-in-class," Dr. Davies said.

Eli Lilly's tirzepatide, sold under the brand name Zepbound for weight loss, works by stimulating GLP-1 along with a second gut hormone called GIP. It was shown to help obese and overweight adults lose 22% of their weight over 72 weeks.

Dr. Davies said it makes sense to have more options for patients, including "theoretical benefits" with amylin, which has been shown in animal studies to boost energy expenditure. If that effect is seen in humans, it could help mitigate the body's metabolic adaptation to weight loss, she said.

Novo Nordisk said it plans to file for regulatory approvals for CagriSema in the first quarter of 2026.

"We expect to see approval maybe around the beginning of 2027," Martin Holst Lange, head of development at Novo Nordisk, told Reuters. The company is conducting several other trials of CagriSema, including measuring its impact on cardiovascular outcomes.

Lange said trial patients given lower doses of the drug often lost as much weight as those given higher doses, suggesting the need for flexibility including longer time periods between dose escalation. "This also allows them to lose their body weight at a pace that isn't too steep. It also mitigates side effects," he said.

(Reporting By Deena Beasley, Editing by Franklin Paul)