Pfizer Inc. and Blackstone Life Sciences entered a strategic co-funding agreement under which funds managed by Blackstone will pay upwards of $1.5 billion in development costs through 2028 for berobenatide.

The investigational, potential first-in-class monthly GLP-1 receptor agonist peptide is currently 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 U.S. regulatory approval of monthly dosing of injectable berobenatide monotherapy for chronic weight management and the achievement of certain commercial sales milestones.¹

Cecile Guegan, chief financial officer and executive vice president, Pfizer, frames the agreement as part of a broader financing strategy for the company’s pipeline. “Our aim is to bring important new medicines to patients while taking a disciplined approach that pairs internal research investments with targeted investment from capital partners,” Guegan says. “Today’s announcement helps us advance our comprehensive obesity program and maintain the financial capacity and flexibility to invest in our broader pipeline across all therapeutic areas.”

What are the terms of the agreement?

Blackstone-managed funds are set to cover up to $1.5 billion of berobenatide’s development costs through 2028.¹ In return, Blackstone becomes eligible for milestone-based payments tied to two conditions: U.S. regulatory approval of monthly dosing of injectable berobenatide monotherapy for chronic weight management, and the achievement of certain commercial sales milestones once the product reaches the market.¹ The structure is expected to keep Blackstone purely as a capital partner rather than a stakeholder in the asset itself, as it holds no rights or ownership in berobenatide, while Pfizer continues to run the program’s operations and make its development decisions.¹

The deal is expected to give Pfizer outside capital to fund one of the larger clinical programs in its pipeline without ceding control of the asset. Under terms of the agreement, Blackstone does not acquire any rights or ownership in berobenatide, while Pfizer retains full operational control and decision-making with respect to the berobenatide program.¹ Any milestone payments, if earned, will be payable to Blackstone over a multi-year period, and funds managed by Blackstone’s perpetual private equity strategy, known as BXPE, will invest alongside funds managed by Blackstone Life Sciences as part of the transaction.¹

As Cheryl Reicin told Pharmaceutical Executive last year, with early-stage companies short on cash and big pharma short on new products, “options-to-buy have come back into vogue” as a way for large drugmakers to pursue multiple shots on goal in the GLP-1 class without loading R&D costs onto their own balance sheets.

What is berobenatide and why does it matter for Pfizer’s pipeline?

Berobenatide, is an investigational, potential first-in-class monthly GLP-1 receptor agonist peptide being studied for chronic weight management and obesity-related comorbidities, including knee osteoarthritis and obstructive sleep apnea.^1,2 The drug is being studied across both weekly and monthly dosing intervals as part of the Vesper clinical program, which spans three trials.² In Vesper-3, which tested a preplanned switch from weekly to monthly injections in adults without type 2 diabetes, berobenatide produced placebo-adjusted weight loss of up to 12.3% at 28 weeks, according to data presented by John B. Buse, MD, PhD, at the American Diabetes Association 2026 Scientific Sessions. Vesper-2 evaluated weekly dosing paired with glycemic improvement in adults who also had type 2 diabetes, while an open-label extension of Vesper-1 tested the drug at its highest weekly dose.²

Pfizer is planning to advance more than 20 trials for obesity and related comorbidities in 2026, including 10 ongoing and planned Phase III trials for berobenatide.¹

Dr. Nicholas Galakatos, global head of Blackstone Life Sciences, points to the deal as a continuation of an existing relationship between the two organizations. “We are pleased to further expand our relationship with Pfizer and support the broad and rigorous development of berobenatide as the anchor of Pfizer’s cardiometabolic pipeline,” Galakatos says. “This collaboration is a good example of our leadership in providing capital solutions at scale to advance important medicines and technologies to patients.”

Sources

1. Pfizer and Blackstone Life Sciences Announce Strategic Funding Agreement for Obesity Program Pfizer November 11, 2026, https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-blackstone-life-sciences-announce-strategic
2. Berobenatide weight loss benefit maintained in shift to monthly dosing, phase 2b data show Clevland Clinic Journal Of Medicine June 6, 2026, https://www.ccjm.org/page/ada-2026/berobenatide-monthly