Pfizer's Monthly Obesity Drug Shows Promising Side Effects

Pfizer has presented data for its experimental monthly obesity drug, berobenatide, indicating a side-effect profile similar to rival weekly injections such as Novo Nordisk's Wegovy. Acquired through last year's purchase of Metsera, Pfizer aims for berobenatide to be the first GLP-1 weight-loss drug administered monthly.

Data from the VESPER-3 trial showed up to 12.3% weight loss in patients without diabetes. Pfizer executives noted that most side effects were mild and gastrointestinal events were mainly at the start of treatment. The drug's long half-life is expected to provide a smoother profile compared to weekly doses.

While a recent JP Morgan analysis suggested an acceptable vomiting rate of 20-25% or lower, Pfizer's data reported a mean nausea rate of approximately 38% and a vomiting rate of about 23.3%. Researchers observed an increase in adverse events when patients shifted from weekly to monthly doses, prompting plans for a more gradual dose escalation in the late-stage program.

Pfizer is positioning berobenatide as a key part of its obesity strategy, following the discontinuation of its own previous weight-loss candidates due to liver safety concerns. The company believes monthly dosing could enhance patient adherence and appeal to a distinct patient segment, differentiating it from current market offerings.