Pfizer Halts Obesity Pill Development Amid Safety Concerns

Pfizer PFE announced that it is discontinuing the development of danuglipron, its investigational oral GLP-1 receptor agonist (GLP-1 RA), which is being developed to treat obesity.

The decision follows a safety signal observed during two dose-optimization studies, in which one study participant experienced a case of potential drug-induced liver injury. Although the individual was asymptomatic and fully recovered after stopping the treatment, Pfizer stated that its decision was based on a comprehensive review of all clinical data generated to date, along with recent regulatory feedback.

While the two dose-optimization studies had met key pharmacokinetic goals and identified a dose with the potential for competitive efficacy and tolerability, the safety concerns ultimately led Pfizer to stop further development of danuglipron.

Obesity Drug Troubles Continue for Pfizer

This is the second time that Pfizer has faced setbacks in connection with the pipeline development of danuglipron. In December 2023, the company announced that it would not move forward with phase III studies on the twice-daily formulation of danuglipron. Though the drug was effective in reducing weight in a phase IIb study, it caused several gastrointestinal side effects like nausea, vomiting and diarrhea. Back then, the company said that the pharmacokinetic study of the once-daily formulation of danuglipron continues, and it will focus on its development.

This also marks the second time in two years that Pfizer has given up on an obesity drug. Back in 2023, Pfizer had dropped the development of another GLP-1-RA candidate, lotiglipron, due to elevated levels of a type of liver enzymes seen in a study.

Following these setbacks, Pfizer has decided to focus on developing its other obesity candidates, which are either in early-stage or mid-stage development. One such candidate is PF-07976016, an investigational GIP receptor being evaluated in a mid-stage study for obesity.

PFE Stock Performance

Year to date, shares of Pfizer have lost nearly 17% compared with the industry’s 7% decline.

LLY, NVO and VKTX Stocks Rise on PFE’s Setback

Post Pfizer’s announcement, shares of Eli Lilly LLY and Novo Nordisk NVO rose 3% and 2%, respectively, on Monday. Both companies dominate the diabetes and obesity market on the back of the tremendous success of their GLP-1 products. Lilly markets its dual GIP and GLP-1 RA, tirzepatide, as Mounjaro for type II diabetes and as Zepbound for obesity. Novo markets its semaglutide drugs as Ozempic pre-filled pen and Rybelsus oral tablet for type II diabetes and as Wegovy injection for weight management.

The obesity market has garnered much interest lately. Per a research conducted by Goldman Sachs, the obesity market in the United States is expected to reach $100 billion by 2030. This is also evident from the fact that LLY and NVO have not only optimized their production capacities but are also developing multiple other novel obesity candidates at a rapid pace.

The implication of Pfizer’s setback is clear for both Eli Lilly and Novo Nordisk — the immediate removal of a potential rival from the highly lucrative GLP-1 market. The latest setback puts Pfizer back at least a couple of years from entering the obesity space.

A company that benefited from Pfizer’s announcement was Viking Therapeutics VKTX, which jumped nearly 11% on Monday. VKTX is currently developing its obesity drug candidate VK2735 in both oral and subcutaneous (SC) formulations. Viking Therapeutics is one of the few companies in this space that has made rapid and encouraging progress with its obesity drug.

Last month, Viking announced that it has completed enrollment in a mid-stage study evaluating oral VK2735, just a couple of months after the study initiation was announced in January. This swift enrollment underscores the growing interest in VK2735 and reflects the rising momentum in the weight-loss drug market, led by the success of Lilly’s Zepbound and Novo’s Wegovy. A late-stage study on the SC version is expected to start before the end of this quarter.

Pfizer Inc. Price

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PFE’s Zacks Ranks

Pfizer currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

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