Pfizer halts development of weight-loss drug danuglipron over safety concerns

On April 14, 2025, Pfizer Inc., a leading global biopharmaceutical company, made the announcement regarding danuglipron (PF-06882961), an oral glucagon-like peptide-1 receptor agonist that was under investigation for chronic weight management. The decision to cease its development followed a troubling incident where a study participant suffered from a liver injury that may have been linked to the drug. This incident has raised significant concerns regarding the safety and tolerability of danuglipron, particularly since a previous formulation, which was administered twice daily, was abandoned in late 2023 after most patients discontinued participation due to various side effects. Additionally, Pfizer had been exploring multiple dosing formats, including the once-daily version, which successfully met certain pharmacokinetic objectives but ultimately could not stave off the adverse safety findings that led to the halt in development. The context surrounding this decision highlights the growing crisis in the weight-loss medication sector, as many pharmaceutical companies compete vigorously in a market projected to be worth over $100 billion. The previous phases of danuglipron’s clinical development showed promise, with efficacy and tolerability profiles that appeared competitive. However, the liver injury incident, combined with a track record of troubling side effects from earlier versions, painted a stark picture of the realities faced in drug development, especially in areas addressing obesity and related metabolic disorders. Despite this setback, Pfizer’s commitment to addressing unmet medical needs in cardiovascular and metabolic conditions remains unwavering. Chris Boshoff, MD, PhD, Pfizer's Chief Scientific Officer, underscored the company's intention to keep pursuing innovative therapies for chronic weight management, including advancements in their oral GIPR antagonist candidate as well as other investigational programs. Biopharmaceutical companies are facing increased pressure to balance drug efficacy with safety, particularly as patients and regulatory agencies demand accountability and thoroughness in clinical trials. The waning prospects of danuglipron serve as a reminder of the inherent uncertainties in drug research and development processes. Although Pfizer is investing resources in ongoing projects, the challenges presented by the danuglipron experience may inform future strategies, including heightened scrutiny and improved safety assessments in their pipelines. Data amassed during the clinical trials will still be disseminated in scientific forums or submitted for future publications, contributing valuable insights into the drug’s profile.