Pfizer said on Wednesday that Blackstone would provide up to $1.5 billion through 2028 to help fund the development of berobenatide, an experimental monthly obesity treatment the drugmaker picked up last year with its up-to-$10 billion acquisition of Metsera.
Under the strategic co-funding agreement, funds managed by Blackstone Life Sciences will pay up to $1.5 billion of development costs for berobenatide, an investigational, potential first-in-class monthly GLP-1 receptor agonist peptide being studied for chronic weight management and obesity-related conditions. In exchange for the funding, Blackstone will be eligible to receive milestone-based payments, subject to US regulatory approval of monthly dosing of injectable berobenatide monotherapy for chronic weight management and achievement of certain commercial sales milestones.
Blackstone will not acquire any rights or ownership in berobenatide, and Pfizer retains full operational control and decision-making with respect to the berobenatide programme. Funds managed by Blackstone’s perpetual private equity strategy will invest alongside funds managed by Blackstone Life Sciences as part of the transaction. The companies did not immediately disclose the size of the milestone payments, which if earned would be payable to Blackstone over a multi-year period.
Pfizer said the deal would give it more flexibility to invest in its broader pipeline across therapeutic areas, adding that it will keep full control over the development programme for the medication. Pfizer plans to advance more than 20 trials for obesity and related comorbidities in 2026, including 10 ongoing and planned Phase 3 trials for berobenatide, which it is developing both as a monotherapy and in combination with other peptides.
Pfizer bought Metsera toward the end of an acquisition spree intended to replace waning revenue from COVID products and looming patent expirations for key drugs, as the drugmaker pushes to build a leading position in the fast-growing weight-loss market.
