Pharmaceutical company Pfizer has halted the development of its once-daily weight loss drug danuglipron after a trial participant experienced liver injury potentially linked to the medication.
The individual showed elevated liver enzyme levels without symptoms, with normalisation occurring swiftly after stopping the treatment, according to company statements. The decision to terminate the oral GLP-1 receptor agonist programme followed a full analysis of clinical data and regulatory consultations—another setback in Pfizer’s efforts to compete in the expanding obesity treatment market.
Pfizer emphasised that the frequency of liver enzyme abnormalities observed across its safety database of over 1,400 patients aligned with approved GLP-1 therapies. Chief Scientific Officer Dr. Chris Boshoff acknowledged the disappointment while reaffirming the company’s commitment to advancing other metabolic disease treatments. The discontinued drug had shown promise in dose-ranging studies, with recent trials identifying formulations that could offer competitive efficacy and tolerability in advanced testing phases.
This latest development compounds challenges for Pfizer in the obesity space, following the discontinuation of a twice-daily danuglipron variant in late 2023 due to tolerability issues and another once-daily candidate halted in mid-2023 over similar liver safety concerns.
The company now shifts focus to earlier-stage candidates, including an oral therapy targeting the GIPR hormone in Phase 2 trials and a separate once-daily GLP-1 drug undergoing initial testing. Former executive Mikael Dolsten previously highlighted the potential of GIPR-targeting drugs for improved patient outcomes, describing GLP-1 applications as having therapeutic potential.
The decision arrives amid intensifying competition in the GLP-1 sector, projected to surpass $150 billion annually within the next decade. Market leaders Novo Nordisk and Eli Lilly currently dominate with injectable therapies like Wegovy and Zepbound, while Novo’s oral Rybelsus remains the only FDA-approved pill in this class, generating $3.38 billion in 2024 diabetes-related sales.
Analysts note Pfizer’s delayed entry positions it years behind rivals, with early-stage candidates unlikely to reach markets before 2030 without partnerships or acquisitions.
Pfizer’s announcement coincides with restructuring efforts as the company seeks to offset declining COVID-19 product revenue through oncology and metabolic disease innovations. While maintaining obesity treatment development as a priority, the firm faces scepticism from investors regarding its ability to carve a significant market share against established competitors.
Industry observers now await critical Phase 3 data from Eli Lilly’s oral GLP-1 candidate orforglipron, which could further transform the industry for non-injectable obesity therapies.
“While we are disappointed to discontinue the development of danuglipron, we remain committed to evaluating and advancing promising programmes in an effort to bring innovative new medicines to patients,” stated Dr. Boshoff.