Pfizer and Blackstone Life Sciences, a private investment platform focused on the bio/pharmaceutical and life sciences sector, of the private equity firm, Blackstone, have announced a strategic co-funding agreement under which funds managed by Blackstone will pay up to a total of $1.5 billion of development costs through 2028 for berobenatide, an investigational monthly glucagon-like peptide-1 (GLP-1) receptor agonist peptide in Phase III development for chronic weight management and obesity-related conditions. Pfizer gained the drug from its $10-billion acquisition of Metsera, a New York-based bio/pharmaceutical company, last November (November 2025).  

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. 

Any milestone payments, if earned, will be payable to Blackstone over a multi-year period. Under the agreement, Blackstone does not acquire any rights or ownership in berobenatide, and Pfizer retains full operational control and decision-making with respect to the berobenatide program. Funds managed by Blackstone’s Perpetual Private Equity Strategies Fund will invest alongside funds managed by Blackstone Life Sciences as part of the transaction. 

Pfizer plans to advance 20+ trials for obesity and related comorbidities in 2026. This includes 10 ongoing and planned Phase III trials for berobenatide for chronic weight management and obesity-related comorbidities, including knee osteoarthritis and obstructive sleep apnea. 

Source: Pfizer