Pfizer has axed (PDF) a phase 2 pulmonary arterial hypertension (PAH) program on business grounds, dealing a setback to a long-running effort to treat the lung disease by targeting BMP9. The move came as part of a wider pipeline clearout that also saw a pair of obesity assets scrapped.
The PAH candidate, dubbed PF-07868489, grew out of counterintuitive findings that inhibiting BMP9 protects rodents against the disease. Having initially explored BMP9 agonists, Pfizer pivoted to studying antagonists as evidence of the beneficial effects of inhibiting the protein emerged. The drugmaker started a phase 1/2 trial of PF-07868489 in 2023 and kicked off a phase 2 open-label extension study in 2025.
Now, one year after starting the open-label extension, Pfizer has terminated the study. The drugmaker attributed the action to business reasons, rather than safety or efficacy concerns. The study was due to end in the second half of 2028.
Pfizer disclosed the termination as part of its third-quarter financial results. The drug candidate was one of two mid-phase assets kicked to the curb in the quarterly update, with Pfizer also confirming the termination of work on the anti-CXCR5 program PF-06835375.
As previously reported, Pfizer recently stopped a phase 2 clinical trial of PF-06835375 in primary immune thrombocytopenia (ITP) early on business grounds. The drugmaker removed its ITP program and a phase 1 assessment of PF-06835375 in lupus from its pipeline in the third-quarter update.
Pfizer axed four other phase 1 programs in the quarterly clear-out period, including two targeted at obesity and chronic weight management. Pfizer has ended development of PF-07999415, an obesity drug candidate against an undisclosed target that entered the clinic last year.
The company shared the news alongside details of the discontinuation of a phase 1 trial of two assets that it acquired from Metsera. The study was testing the GIPR agonist PF-08654696 in combination with the GLP-1 receptor agonist PF-08653944. Pfizer continues to test the GLP-1 candidate in other settings, but the phase 1 program was the only active trial of the GIPR agonist.
News of the discontinuation comes three months after Pfizer ended development of a GIPR antagonist, PF-07976016. Scientists have found that GIPR agonism and antagonism decrease body weight. Eli Lilly’s blockbuster GLP-1 drug tirzepatide activates GIPR, while Amgen’s late-phase asset MariTide blocks the receptor. Pfizer has pulled back from both approaches in quick succession.
The other two discontinued programs are both selective KRAS inhibitors that were in phase 1 solid tumor trials. The assets, PF-07985045 and PF-07934040, entered phase 1 in 2024. Pfizer terminated the study of PF-07985045 in May on business grounds but still listed the program as active in its second-quarter earnings. In July, Pfizer stopped enrollment in the PF-07934040 trial, well short of its recruitment goal.
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