Pfizer has halted development of its experimental weight-loss pill, danuglipron, after a patient in a clinical trial developed a liver injury, dealing a blow to the company’s ambitions in the rapidly growing $100 billion anti-obesity drug market.
As reported by The Times UK, the U.S.-based pharmaceutical titan made the decision following a comprehensive safety review of clinical data and recent input from regulatory bodies. The once-daily oral version of danuglipron was being tested in mid-stage trials, but the program was discontinued after the emergence of potential liver-related side effects.
Pfizer had already abandoned a twice-daily formulation of the drug in late 2023, after high dropout rates due to side effects such as nausea and vomiting.
Danuglipron belongs to a class of drugs targeting GLP-1 — a hormone that regulates appetite and blood sugar — which has formed the backbone of the current generation of anti-obesity medications. The market is currently dominated by Novo Nordisk’s semaglutide-based treatments, sold as Ozempic and Wegovy, and Eli Lilly’s tirzepatide, marketed under Mounjaro and Zepbound.
Pfizer’s withdrawal underscores the growing challenge facing pharma companies eager to enter the lucrative obesity drug market. Global players such as AstraZeneca and Roche have been making aggressive moves, with Roche recently signing a $5.3 billion licensing deal with Denmark’s Zealand Pharma to advance its weight-loss pipeline.
Despite the setback, Pfizer said it remains committed to obesity and metabolic disease research. “Cardiovascular and metabolic diseases including obesity remain important areas of unmet medical need,” said Chris Boshoff, the company’s Chief Scientific Officer. He added that Pfizer will continue to develop other oral obesity treatments targeting different hormones.
Market reactions were muted. Pfizer shares remained flat in pre-market trading on Wall Street, while competitors gained ground: Eli Lilly rose by 1.8% and Novo Nordisk saw shares jump 3.8% in Copenhagen.
Pfizer, which became a household name during the COVID-19 pandemic thanks to its partnership with BioNTech on the Comirnaty vaccine, has been grappling with a sharp decline in revenue since pandemic-era sales peaked at over $100 billion in 2022. Its stock has fallen more than two-thirds since late 2021 as the company struggles to replace lost revenue from its vaccine and antiviral drug Paxlovid.
Under CEO Albert Bourla, Pfizer has embarked on a major restructuring campaign to stabilize its business, including job cuts and closures — notably at its UK research facility at Discovery Park in Sandwich, Kent.
While the end of the danuglipron program marks a significant roadblock, Pfizer’s continued investment in early-stage obesity treatments signals that it has not abandoned the high-stakes race for the next blockbuster drug in metabolic health.
