Pfizer’s monthly GLP-1 data prompts caution as new rival approaches Phase III
Citi has reiterated its 'neutral' stance on Novo Nordisk (NYSE:NVO), warning that competition in the obesity drug market continues to intensify following promising phase II results from Pfizer's candidate MET-097i.
At its full-year 2025 results, Pfizer released topline data from the VESPER-3 trial showing its monthly GLP-1 treatment for obesity, Metsera, achieved weight loss comparable to Eli Lilly’s Zepbound and Novo’s own CagriSema.
The 4.8mg dose also delivered numerically greater efficacy than Wegovy at 28 weeks.
Gastrointestinal side effects were deemed tolerable, with approximately 9% of patients discontinuing due to adverse events across lower and medium doses. Citi noted this rate was slightly above the 6–7% typically observed with GLP-1 treatments but still within a manageable range.
Pfizer plans to advance 3.2mg, 4.8mg and a higher, untested 9.6mg dose into phase III. Internal modelling suggests a placebo-adjusted weight loss of up to 15.8% could be possible at the highest dose.
While monthly dosing may offer a convenience advantage, Citi said tolerability at higher doses remains a key question. Full trial data are expected at the American Diabetes Association meeting in June.
Citi concluded that MET-097i strengthens the pipeline of credible GLP-1 challengers and justifies its continued caution on Novo amid growing market competition.