Pfizer Reports Moderate Weight Loss Results from Newly Acquired Drug Amid Mixed Q4 Earnings

Pfizer Inc. presented topline findings from its ongoing Phase 2b VESPER-3 clinical trial evaluating the weight management drug PF'3944 (also known as MET-097i), alongside its fourth-quarter 2025 financial results. PF'3944 is an ultra-long-acting, injectable glucagon-like peptide-1 (GLP-1) receptor agonist recently added to Pfizer’s portfolio through its substantial $10 billion acquisition of Metsera, Inc. The VESPER-3 study involves monthly maintenance dosing in adult patients with obesity or overweight conditions excluding those with type 2 diabetes. At the 28-week mark, the data revealed that participants receiving PF'3944 achieved statistically significant weight reductions with up to 12.3% mean placebo-adjusted weight loss. This was observed predominantly in two dosage groups designated as Arms 1 and 3, which correspond to low and medium monthly maintenance doses slated for Phase 3 evaluations. Specifically, Arm 1 achieved a 10% placebo-adjusted weight loss, while Arm 3 reached 12.3% at 28 weeks. Importantly, the results indicate continued and meaningful weight loss over time without evidence of plateau at the measured point, highlighting a persistent drug effect in maintaining weight reduction upon switching to monthly administration. Safety assessments through week 28 underscored a favorable tolerability profile consistent with the GLP-1 receptor agonist class. Treatment-emergent gastrointestinal events, common with this drug category, were mostly mild to moderate, with at most one case of severe nausea or vomiting reported per dosage group and no incidents of severe diarrhea. Earlier data from a related Phase 2b trial, VESPER-1, released in September 2025, showed up to 14.1% weight reduction after 28 weekly doses of MET-097i, providing additional context on the drug's efficacy with more frequent administration. Looking ahead, Pfizer plans to launch a significant clinical development program for PF'3944 in 2026, aiming to initiate ten Phase 3 trials as part of a broader pipeline comprising over twenty planned or ongoing studies. Turning to Pfizer’s fourth-quarter earnings, the company posted adjusted earnings of $0.66 per share, surpassing the prior-year figure of $0.63 as well as the consensus estimate of $0.57. Revenue for the quarter totaled $17.56 billion, representing a 1% year-over-year decrease but exceeding the consensus forecast of $16.96 billion. This revenue decline equated to an operational decrease of 3%, predominantly attributable to lower sales from COVID-19 related products, which was partially offset by gains in other pharmaceutical segments. The operational decline reflects waning demand for Pfizer's COVID-19 vaccines and treatments amid evolving pandemic dynamics. Notably, Comirnaty vaccine sales fell 35% operationally to $2.27 billion, driven mainly by narrower vaccination recommendations within the U.S. and delays in approval of an updated variant-specific vaccine. Similarly, Paxlovid antiviral revenues declined 70% operationally to $218 million, impacted by reduced infection rates domestically and internationally and diminished government purchases abroad. Conversely, key non-COVID products demonstrated strength: the Vyndaqel family of heart drugs saw a 7% operational revenue increase to $1.69 billion; the blood thinner Eliquis attained 8% operational growth with sales of about $2.02 billion; the pneumococcal vaccine Prevnar rose 8% operationally to $1.71 billion; and the respiratory syncytial virus (RSV) vaccine Abrysvo contributed $481 million in sales. Oncology agent Ibrance posted a 5% sales decrease to $1.04 billion. Excluding revenues from Comirnaty and Paxlovid, Pfizer reported a 9% operational growth in fourth-quarter revenues, illustrating ongoing resilience in its broader pharmaceutical portfolio. Looking forward to fiscal 2026, Pfizer reaffirmed its guidance for adjusted earnings ranging between $2.80 and $3.00 per share, close to the consensus expectation of $2.97. Sales forecasts remain stable in the $59.5 billion to $62.5 billion bracket, aligning closely with analysts’ estimates of approximately $61.06 billion. The company anticipates approximately $5 billion in revenue from COVID-19 products in 2026 but expects a year-over-year negative sales impact of around $1.5 billion due to loss of exclusivity on certain products. Furthermore, the guidance encompasses anticipated uncertainties such as the impact of Most-Favored-Nation drug pricing rules, the TrumpRx initiative, and existing tariffs. Following the announcement, Pfizer’s stock experienced a notable decline of 5.10%, trading near $25.30 in the premarket session as of the last update. Market participants appeared to respond cautiously to the modest weight loss outcomes of the newly acquired drug and the mixed earnings dynamics amid a challenging healthcare pricing environment. In summary, Pfizer’s Phase 2b results for PF'3944 reinforce its potential as a once-monthly injectable treatment for obesity, delivering meaningful but moderate weight loss. While the favorable safety profile and pipeline expansion provide optimism, the financial results illustrate the company’s ongoing navigation through COVID-19 revenue declines and external market pressures.