In a significant setback for obesity treatment research, Pfizer has announced that it will discontinue the development of its once-promising oral medication, danuglipron. The decision comes after the drug, which was undergoing phase three clinical trialsthe final testing stage before regulatory approvalwas linked to a possible drug-induced liver injury. This adverse event prompted the company to reassess the safety of the treatment, leading to the decision to halt its studies.

The liver injury was reported by a participant in one of the clinical trials, who experienced symptoms that resolved after discontinuing the medication. Although Pfizer did not disclose the specifics of the injury, the incident raised concerns about the safety profile of danuglipron, which had shown potential as a convenient alternative to existing obesity treatments.

Despite this setback, Pfizer remains committed to developing other obesity treatments that are currently in earlier stages of testing. A company official reiterated this commitment in a statement, emphasizing the importance of continuing the pursuit of innovative options for managing obesity, a condition that affects millions worldwide.

The pharmaceutical industry has increasingly turned its attention to obesity treatment, recognizing it as a lucrative market. For instance, Eli Lilly and Co.'s Zepbound generated impressive sales, nearing $5 billion during its first full year on the market in 2024. However, many of the leading treatments, like Zepbound and Novo Nordisks Wegovy, require injections, prompting a strong demand among consumers and healthcare providers for a more user-friendly, pill-based option.

Pfizers journey with danuglipron has not been without its challenges. In late 2023, the company had already decided to abandon a twice-daily formulation of the same drug after more than half of the participants in a clinical trial dropped out, indicating significant issues with adherence. This history of difficulties raises questions about the future viability of oral obesity treatments.

As the news broke, Pfizer's stock reflected this uncertainty: shares were down by 7 cents to $21.84 in pre-market trading on Monday, signaling investor concerns over the companys ability to navigate this setback in the competitive landscape of obesity treatment.