Pfizer presented data on Saturday that showed a monthly dose of an experimental obesity drug it acquired through its purchase of Metsera last year had a similar side-effect profile as rival Novo Nordisk’s weekly injection Wegovy.
The drugmaker hopes the compound, called berobenatide, can be the first GLP-1 weight-loss drug offered as a monthly shot as the company works to differentiate the compound from blockbuster drugs like Wegovy and Eli Lilly’s Zepbound.
In February, Pfizer said the compound showed up to 12.3 per cent weight loss in patients without diabetes in its mid-stage VESPER-3 trial.
Analysts are looking to the drug’s side-effect profile to assess whether it will be commercially viable.
Pfizer executives said most patients experienced few or mild side effects, with gastrointestinal events largely limited to early doses and clustered close to when patients received the shot. The results were presented at the American Diabetes Association meeting in New Orleans.
“Because of the very long half life here, you get a very smooth profile compared to weeklies,” Pfizer Chief Internal Medicine Officer Jim List said in an interview. “When you give it monthly … it’s very front-loaded. It does not persist through the month.”
List said that researchers did see an increase in adverse events after patients went from a weekly to a monthly dose in the trial, so the company plans to increase the dose more gradually in its late-stage program.
Pfizer presented data on Saturday showing that the mean nausea rate in all the arms of the VESPER-3 study was around 38% and the mean vomiting rate was about 23.3 per cent.
Last month, JP Morgan analyst Chris Schott said that investors would be looking for the vomiting rate for the drug in the trial to be “20-25 per cent or lower.”
Around 25 per cent of patients on Novo Nordisk’s Wegovy vomited during that company’s weight-loss trial, while around 44 per cent reported nausea.
The experimental drug sits at the center of Pfizer’s obesity strategy following its $10 billion acquisition of Metsera last year. That brought the drugmaker a new pipeline of metabolic therapies after it was forced to discontinue two of its own weight-loss drug candidates due to liver safety concerns.
Pfizer is hoping monthly dosing of berobenatide can differentiate the drug from the weekly injections on the market, arguing that less frequent dosing could improve adherence and be attractive to a different set of patients.
Published on June 6, 2026
