Lack of Confirmation on Pfizer-Blackstone Funding Deal Leaves Obesity Program Details Unresolved
Key Facts
The announcement of a funding deal between Pfizer and Blackstone Life Sciences to develop an obesity treatment, and its terms, could not be verified through a reliable, publicly available source. The reported funding amount, the party responsible for development costs and the deal’s timeline therefore cannot be confirmed. The report of an agreement remains unresolved, including whether the funding would cover the berobenatide program. Available data on the candidate come from earlier Pfizer announcements and do not establish that a deal was signed on November 11, 2026. In the latest closing data available, Pfizer shares closed at $29.36 on November 10, while Blackstone shares closed at $122.53 on the same day.
In the background to the program, Pfizer said in results published on June 6, 2026, that a 32-week exploratory extension of the VESPER-1 study showed placebo-adjusted weight loss of 15.9%. The result included participants who switched from the placebo group to berobenatide at a dose of 2.4 mg weekly. The company said the weight loss had not plateaued by week 32 of the extension, or week 60 of the full study. The result describes the participants’ course, dose and specific period in the extension; it does not confirm the outcome of any subsequent funding deal. Nor does it alone establish when the treatment may become available or the outcome of a pivotal study.
In the same announcement, Pfizer said it planned to submit 10 Phase 3 studies of berobenatide during 2026, as part of a broader program comprising more than 20 trials in obesity and its complications. The plan places the candidate among a group of late-stage studies the company intends to advance during the year, while the broader program includes trials addressing obesity and its complications. But the plan reflects what Pfizer announced in June; it does not confirm that all 10 studies have started or specify their results. Those figures also do not clarify the terms of any funding from Blackstone or whether it would cover part of the program. What can be attributed to the company here is limited to the study plan and program scope as stated in its announcement.
Among other clinical results reported by Pfizer, average placebo-adjusted weight loss in the VESPER-3 study was about 12.3% at week 28, according to company data published in 2026. This result differs from the VESPER-1 extension figure because it concerns a separate study and measurement period; Pfizer’s statement also described it as average placebo-adjusted weight loss. It provides additional context for the data the company has published on berobenatide, with each figure tied to its study design and specified measurement point. These figures alone do not allow a direct comparison between the two studies or establish the impact of a deal that could not be verified.
On the monthly dose, Pfizer said on June 6 that its pivotal Phase 3 VESPER-6 study was open for enrollment. The study is evaluating a monthly maintenance dose of berobenatide in adults with obesity or overweight. This provides information about the clinical path for the monthly dose, but does not show that the program received funding from Blackstone or confirm the terms of an agreement announced at a later date. The available statement here did not include a timeline for VESPER-6 results. Pfizer’s announced timing for the broader program was its plan to submit 10 Phase 3 studies during 2026.
Blackstone Life Sciences describes its activities as including the design, financing and execution of clinical trials. The unit says it has had more than 200 drugs reach the market and that its team includes 21 physicians or Ph.D. holders; it also reports a Phase 3 success rate of 87%. The company said these figures were as of September 30, 2026. The data describe the unit’s experience and scope of activity as presented by the company, but do not establish Blackstone’s involvement in financing berobenatide. Without independent verification of the deal announcement and its terms, the funding amount, cost allocation and timeline remain unconfirmed.
The available closing prices for the two shares are for the November 10, 2026, session: Pfizer closed at $29.36 and Blackstone at $122.53. These prices represent the closing levels on that date and do not describe share movements after it. The facts provided include no comparative data from other sessions that would allow daily changes to be measured or the closing prices to be linked to any deal announcement. The latest market information that can be cited here is therefore the dated closing prices, alongside earlier clinical data and Pfizer’s announced Phase 3 plan.