Pfizer's $4.9B Bet on Metsera's Obesity Drug Shows Promise in Mid-Stage Trial

Pfizer's recent $4.9 billion acquisition of Metsera appears to be paying off, as the biotech's investigational long-acting GLP-1 therapy, MET-097i, demonstrates encouraging efficacy in a mid-stage clinical trial. The drug's performance in weight reduction and tolerability profile positions it as a potential competitor to established obesity treatments, supporting Pfizer's strategic move in the rapidly growing market for weight loss medications.

VESPER-1 Trial Results Highlight MET-097i's Efficacy

The Phase IIb VESPER-1 trial has yielded promising results for MET-097i, Metsera's once-monthly subcutaneous injection for obesity treatment. At the 28-week mark, patients receiving a 1.2-mg dose of MET-097i experienced a 14.1% placebo-adjusted reduction in body weight. This outcome is particularly noteworthy when compared to Eli Lilly's blockbuster drug tirzepatide, which achieved approximately 13% placebo-adjusted weight loss over the same duration.

Metsera reports that some individual responses to MET-097i reached as high as 26.5% weight reduction. Furthermore, an exploratory analysis at 36 weeks revealed "substantial continued weight loss," suggesting that the drug's full potential may not yet have been reached. According to analysts at Leerink Partners, this ongoing weight loss indicates that "no plateau had been reached," hinting at the possibility of even greater efficacy with extended treatment.

Tolerability Profile Shows Promise in VESPER-3 Study

Alongside efficacy data, Metsera has released tolerability findings from the VESPER-3 study, another Phase IIb trial. Over a 12-week follow-up period, the placebo-adjusted risk of common side effects associated with GLP-1 therapies was assessed across four MET-097i dose arms, each with varying strengths and titration schedules.

The results show a placebo-adjusted risk of nausea ranging from 12.8% to 23.9%, while diarrhea risk ranged from 0% to 11%, and vomiting risk from 9.2% to 17%. Analysts at Leerink Partners suggest that these safety findings indicate "promise for the tolerability profile of MET-097i to be better than tirzepatide in SURMOUNT-1." However, they caution that the longer duration of Lilly's SURMOUNT-1 trial (72 weeks) allowed more time for adverse events to accumulate.

Implications for Pfizer and the Obesity Drug Market

The positive mid-stage results for MET-097i bode well for Pfizer's recent acquisition of Metsera. Analysts at BMO Capital Markets noted that this early look "gives credence not only to the Metsera asset but also the internal due diligence in sourcing the deal." The performance of MET-097i in these trials supports Pfizer's decision to enter the competitive obesity drug market with a significant investment.

Metsera is not limiting its obesity strategy to MET-097i as a monotherapy. The company is also exploring combination therapies, testing MET-097i with an amylin analog and a GIP receptor agonist. Additionally, Metsera is developing an oral formulation of MET-097i and a prodrug version for maintenance dosing, potentially expanding the drug's application and market reach.

As the obesity treatment landscape continues to evolve, Pfizer's acquisition of Metsera and the promising results of MET-097i position the pharmaceutical giant to compete with established players like Eli Lilly and Novo Nordisk. With a Phase III program for MET-097i set to begin later this year, the industry will be watching closely to see if Pfizer's multi-billion dollar bet will yield a new contender in the lucrative weight loss medication market.