Blackstone to Provide Pfizer Up to $1.5 Billion for Monthly GLP-1 Berobenatide Development

Blackstone Life Sciences will provide Pfizer with up to $1.5 billion through 2028 to fund development of berobenatide, an investigational monthly glucagon-like peptide-1 receptor agonist (GLP-1 RA) peptide for chronic weight management and obesity-related conditions.¹ In exchange, Blackstone is eligible for milestone-based payments tied to US regulatory approval of monthly injectable berobenatide monotherapy for chronic weight management and to certain commercial sales milestones.¹

“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,” said Cecile Guegan, chief financial officer and executive vice president at Pfizer.¹

How is the deal structured?

Under the co-funding agreement, funds managed by Blackstone will pay up to $1.5 billion of berobenatide’s development costs.¹ Any milestone payments, if earned, will be paid to Blackstone over a multiyear period.¹ Blackstone does not acquire any rights or ownership in berobenatide, and Pfizer retains full operational control and decision-making over the program.¹ Funds from Blackstone’s perpetual private equity strategy will invest alongside Blackstone Life Sciences funds.¹

Nicholas Galakatos, PhD, global head of Blackstone Life Sciences, called berobenatide “the anchor of Pfizer’s cardiometabolic pipeline.”¹

The agreement follows a growing pattern of large pharmaceutical companies sharing late-stage development costs with private capital. Blackstone Life Sciences closed a record $6.3 billion fund in March 2026 and has struck similar arrangements with Merck for its antibody-drug conjugate sacituzumab tirumotecan and with Teva for its anti-TL1A antibody duvakitug.²˒³ In the Teva deal, Blackstone committed $400 million over four years in exchange for an approval milestone payment plus sales-based payouts and royalties.²

How capital moves through the industry shapes how much research gets funded. In a BioPharm International video interview, Sara Jane Demy, chief executive officer of Demy-Colton, said, “Every time a company makes a move like that, or there is an acquisition, it frees up capital,” adding that it “puts more capital back into the space, and enables more research and development to be done.”

Where did berobenatide come from?

Berobenatide, also known as PF’3944, was previously Metsera’s MET-097i.⁴ Pfizer gained the program when it completed its acquisition of Metsera in November 2025 for $65.60 per share in cash, plus a contingent value right of up to $20.65 per share, in a deal valued at up to about $10 billion.⁵ The acquisition also brought Pfizer MET-233i, a monthly amylin analog being evaluated alone and in combination with MET-097i.⁵

What do the clinical data show?

In the Phase 2b VESPER-3 trial, participants received weekly berobenatide during a titration period and then switched to monthly dosing.⁴ All four dose regimens produced significantly greater weight loss than placebo at Week 28, with placebo-adjusted weight loss of up to 12.3% with the 4.8-mg monthly regimen, and weight loss had not plateaued.⁴˒⁶ Gastrointestinal adverse events were mostly mild or moderate.⁴ As BioPharm International® reported when the data were first released, the results support advancing monthly dosing into phase 3.

“If approved, berobenatide has the potential to be not only effective, but practical and sustainable in real life,” said John B. Buse, MD, PhD, who presented the results at the American Diabetes Association Scientific Sessions in June.⁶

Pfizer is entering a crowded field. Eli Lilly’s triple agonist retatrutide produced up to 28.3% weight loss in a phase 3 trial, and Zealand Pharma and Roche have advanced the amylin analog petrelintide to Phase 3, as BioPharm International has reported.

What happens next?

Pfizer plans to advance more than 20 trials for obesity and related comorbidities in 2026, including 10 ongoing and planned phase 3 trials of berobenatide.¹ Those studies include chronic weight management and obesity-related comorbidities such as knee osteoarthritis and obstructive sleep apnea.¹ Pfizer is also developing berobenatide as a monotherapy and in combination with other nutrient-stimulated hormone peptides, including amylin analogs.¹

References

1. Pfizer and Blackstone Life Sciences announce strategic funding agreement for obesity program. News release. Pfizer; November 11, 2026. Accessed November 12, 2026.
2. Gardner J. Blackstone puts $400M into Teva, Sanofi gut disease drug. BioPharma Dive. Published March 4, 2026. Accessed November 12, 2026.
3. Blackstone announces final close of record $6.3 billion life sciences fund, the largest private fund dedicated to life sciences. News release. Blackstone; March 30, 2026. Accessed November 12, 2026.
4. Pfizer’s ultra-long-acting injectable GLP-1 RA shows robust and continued weight loss with monthly dosing in Phase 2b trial. News release. Pfizer; February 3, 2026. Accessed November 12, 2026.
5. Pfizer completes up to $10 billion acquisition of Metsera. Indian Pharma Post. Published November 14, 2025. Accessed November 12, 2026.
6. Berobenatide weight loss benefit maintained in shift to monthly dosing, phase 2b data show. Cleveland Clinic Journal of Medicine. Published June 2026. Accessed November 12, 2026.