Pfizer has secured a financing commitment of up to $1.5 billion from Blackstone Life Sciences to accelerate development of berobenatide, its experimental once-monthly obesity treatment.
The agreement, announced November 11, will cover development expenses through 2028, giving the pharmaceutical company additional financial flexibility as it expands its presence in the increasingly competitive weight-management market.
Under the arrangement, funds managed by Blackstone will finance eligible development costs, while Pfizer will remain the sole owner of berobenatide and retain control over its clinical program and commercial decisions. In return, Blackstone will qualify for milestone-based payments contingent on U.S. regulatory approval of monthly injectable berobenatide as a standalone treatment for chronic weight management and the achievement of specified sales targets. The companies have not disclosed the potential value of these payments.
The arrangement does not give Blackstone an ownership stake in the medicine or control over its development. Its investment will instead be structured around the drug’s regulatory and marketing progress, with any earned payments distributed over multiple years. Blackstone’s perpetual private equity strategy, BXPE, will participate alongside funds managed by its Life Sciences division.
Berobenatide, previously known as PF’3944, entered Pfizer’s portfolio through its acquisition of Metsera, a biotechnology company focused on obesity and metabolic diseases. The transaction, valued at up to approximately $10 billion, gave Pfizer access to a collection of experimental metabolic treatments as it sought to strengthen its pipeline against established competitors.
The investigational medicine belongs to the glucagon-like peptide-1 (GLP-1) receptor agonist class, which has transformed obesity treatment through drugs that help regulate appetite and food intake. Unlike currently marketed weekly injections, berobenatide is being developed for administration once a month.
If successful, the longer dosing interval could offer patients an alternative that requires fewer injections while maintaining meaningful weight-management benefits.
Pfizer intends to pursue an extensive clinical development program for the candidate. Its plans for 2026 include more than 20 trials involving obesity and related conditions, with 10 ongoing or planned Phase 3 studies specifically evaluating berobenatide. Research is examining both standalone treatment and combinations with other nutrient-stimulated hormone peptides, including amylin analogs. Potential applications extend beyond weight reduction to obesity-associated conditions such as obstructive sleep apnea and knee osteoarthritis.
Cecile Guegan, Pfizer’s Chief Financial Officer and Executive Vice President, said the agreement reflects the company’s intention to combine its own research investment with carefully selected external financing. She explained that the additional capital would support its obesity development strategy while preserving financial capacity for research across other therapeutic areas.
The agreement also builds on an established financial relationship between the two organizations. In 2023, Blackstone committed up to $550 million toward development expenses for selected Pfizer medicines. The latest arrangement represents a substantially larger collaboration, reflecting the scale of investment required to advance berobenatide through late-stage clinical development.
Nicholas Galakatos, Global Head of Blackstone Life Sciences, described the deal as an expansion of the firms’ existing relationship. He indicated that Blackstone views berobenatide as an important component of Pfizer’s cardiometabolic portfolio and sees the partnership as an opportunity to deploy substantial capital toward advancing new medicines.
Pfizer Secures Major Funding for Berobenatide
Pfizer has secured a major strategic funding agreement with Blackstone Life Sciences to support the development of berobenatide, an investigational monthly GLP-1 receptor agonist for chronic weight management and obesity-related conditions. Under the agreement, Blackstone-managed funds could provide Pfizer with up to $1.5 billion in development funding through 2028. Pfizer
The deal gives Pfizer additional financial flexibility while allowing the company to continue advancing its ambitious obesity research program. Pfizer will retain full operational control and decision-making authority over berobenatide, while Blackstone may receive milestone-based payments linked to regulatory approval and commercial performance.
