Berobenatide

updated

Berobenatide (also MET-097i, MET097 and PF-08653944) is Pfizer's investigational injectable GLP-1 receptor agonist, acquired with Metsera in November 2025. Its efficacy evidence is one set of sponsor-posted phase 2b results from a treatment-adherent analysis (239 adults, 28 weeks: -12.45% at 1.2 mg weekly versus +1.67% on placebo) and Pfizer company statements, and a PubMed search on 10 October 2026 found no peer-reviewed report. Phase 3 began in December 2025 and has no results, and no regulatory approval was found.

GLP-1 receptor agonist peptide (exendin-4 derivative)

  • Berobenatide is a WHO Proposed INN (List 133, 2025) for an exendin-4 derivative carrying a fatty-diacid group, formula C232H369N57O68, CAS 3028974-74-2. Pfizer-sponsored registry records list MET-097i, MET097 and PF-08653944 as other names for the same molecule.
  • In VESPER-1 (239 US adults with obesity or overweight, 28 weeks, weekly subcutaneous injection), the sponsor-posted least-squares mean percent change in body weight at week 28 was +1.67% on placebo and -6.41% to -12.45% across 0.4 to 1.2 mg. The placebo-adjusted difference at 1.2 mg was -14.13% (95% CI -16.67 to -11.59).
  • The VESPER-1 analysis excludes data after treatment discontinuation, non-compliance or other weight-loss drugs, so it is a treatment-adherent result, not an intent-to-treat result. The results are posted on ClinicalTrials.gov and have no peer-reviewed paper.
  • Pfizer reported on 3 February 2026 placebo-adjusted weight loss of up to 12.3% (efficacy estimand) in VESPER-3 after 12 weekly doses and monthly dosing to week 28. A 15.9% figure reported on 5 June 2026 from an exploratory extension is not placebo-adjusted and should not be compared with it.
  • Phase 3 has started: a ClinicalTrials.gov search on 10 October 2026 returned 8 phase 3 registrations, including VESPER-4 (3,578 enrolled, started 19 December 2025). None has posted results.
  • On 10 October 2026 openFDA Drugs@FDA returned no application records for berobenatide and a DailyMed search returned no labels.

What is berobenatide, and is it approved anywhere?

Berobenatide is the WHO Proposed INN for an exendin-4 derivative carrying a fatty-diacid group, and it is one molecule with MET-097i, MET097 and PF-08653944. Pfizer acquired it with Metsera on 13 November 2025. No regulatory approval was found: openFDA and DailyMed searches on 10 October 2026 returned no application records and no labels.

Berobenatide is a WHO Proposed INN (List 133, WHO Drug Information Vol. 39 No. 2, 2025), defined as an exendin-4 derivative carrying a 19-carboxynonadecanoyl-glutamyl-lysine fatty-diacid group, with the stated action GLP-1 receptor agonist. The entry lists the formula C232H369N57O68 and CAS 3028974-74-2. WHO INN entries carry no company codes, so the link to the codes rests on registry records and a Pfizer release. A PubChem name search for berobenatide, MET-097 and MET-097i returned no compound record on 10 October 2026.

Berobenatide, MET-097i, MET097 and PF-08653944 are one molecule. The Pfizer-sponsored record NCT07823608 lists the intervention Berobenatide with the other names MET-097i and PF-08653944. Pfizer's VESPER-4 record NCT07311850 lists MET097 with the other name PF-08653944, and its VESPER-5 record NCT07400653 lists PF-08653944 with the other name MET097. The results posted on the earlier phase 2b record NCT06712836 label the arms Berobenatide. Pfizer's press release of 3 February 2026 states PF-08653944 (PF'3944; previously called MET-097i). MET-097i is the injectable. No primary record on any oral MET-097 product from Metsera was retrieved, and none is covered here.

Pfizer is the developer through its acquisition of Metsera, Inc. Pfizer's Form 8-K of 13 November 2025 reports that it completed the acquisition that day at $65.60 per share in cash (enterprise value about $7.0 billion) plus a contingent value right of up to $20.65 per share.

No regulatory approval was found. On 10 October 2026 openFDA Drugs@FDA returned no application records for berobenatide, and a DailyMed search returned no labels. The contingent value right includes $6.40 payable on FDA approval of monthly MET-097i monotherapy, which shows that no such approval had occurred by 13 November 2025.

WHO Proposed INN List 133 (2025): exendin-4 derivative, GLP-1 receptor agonist

Chemical identity record

World Health Organization. Proposed International Nonproprietary Names: List 133. WHO Drug Information, Vol. 39, No. 2, 2025.

Berobenatide is defined as an exendin-4 derivative carrying a 19-carboxynonadecanoyl-glutamyl-lysine fatty-diacid group, with the stated action GLP-1 receptor agonist. The entry lists the formula C232H369N57O68 and CAS 3028974-74-2. WHO INN entries carry no company codes. A PubChem name search for berobenatide, MET-097 and MET-097i returned no compound record on 10 October 2026.

Participants / model
Molecular identity, not a clinical population
Treatment
Peptide, subcutaneous
Follow-up
Not applicable
Study design
Official WHO nomenclature record (Proposed INN list)
Funding
not stated in the source

The link between the INN and the company codes rests on the sponsor-registered other names and Pfizer's press release, because the WHO list carries no codes.

Read the original source
Registry records: Berobenatide, MET-097i, MET097 and PF-08653944 as one molecule

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07823608, with records NCT07311850 (VESPER-4), NCT07400653 (VESPER-5) and NCT06712836 (VESPER-1). Read on 10 October 2026.

The Pfizer-sponsored record NCT07823608 lists the intervention Berobenatide with other names MET-097i and PF-08653944. Pfizer's VESPER-4 record NCT07311850 lists MET097 with other name PF-08653944, and its VESPER-5 record NCT07400653 lists PF-08653944 with other name MET097. The results posted on the Metsera-era phase 2b record NCT06712836 label the arms Berobenatide. MET-097i is the injectable; no primary record on any oral Metsera MET-097 product was retrieved and none is covered here.

Participants / model
Sponsor and code identity, not a clinical population
Treatment
Subcutaneous injection
Follow-up
Not applicable
Study design
Trial registry records
Funding
Sponsor: Pfizer

Berobenatide, MET-097i, MET097 and PF-08653944 are treated as one molecule on this page.

Read the original source
Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source
Company filing, 13 November 2025: Metsera acquisition; no approval found

Regulatory record

Pfizer Inc. Form 8-K dated 13 November 2025, U.S. Securities and Exchange Commission. openFDA Drugs@FDA and DailyMed searches run on 10 October 2026.

Pfizer completed its acquisition of Metsera, Inc. on 13 November 2025 at $65.60 per share in cash (enterprise value about $7.0 billion) plus a contingent value right of up to $20.65 per share, which includes $6.40 payable on FDA approval of monthly MET-097i monotherapy. No regulatory approval was found: on 10 October 2026 openFDA Drugs@FDA returned no application records for berobenatide and a DailyMed search returned no labels. The contingent value right tied to a future FDA approval shows none had occurred by 13 November 2025.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Filing dated 13 November 2025; searches run on 10 October 2026
Study design
Company filing; US regulator database searches
Funding
not stated in the source

A search result shows what the databases held on that date. Pfizer is the developer through the Metsera acquisition.

Read the original source

What did the registry-posted phase 2b results show?

In VESPER-1 (239 US adults, 28 weeks), least-squares mean percent change in body weight at week 28 was +1.67% on placebo and -6.41% to -12.45% on 0.4 to 1.2 mg weekly, a placebo-adjusted difference of -14.13% at 1.2 mg. The analysis is treatment-adherent, not intent-to-treat, and was posted by the sponsor with no peer-reviewed paper.

VESPER-1 (NCT06712836) was a phase 2b, randomized, double-blind, placebo-controlled trial of 28 weeks in 239 adults (eligibility age 18 to 70) with obesity or overweight at US sites. The groups were placebo 48, 0.4 mg 48, 0.6 mg 48, 0.9 mg 47 and 1.2 mg 48, given weekly by subcutaneous injection (the sponsor's code MET097).

The sponsor posted results on ClinicalTrials.gov. Least-squares mean percent change in body weight at week 28 was +1.67 (SE 0.90) on placebo and -6.41, -8.36, -11.29 and -12.45 on 0.4, 0.6, 0.9 and 1.2 mg weekly. These are changes from baseline. The differences versus placebo, which are placebo-adjusted, were -8.09 (95% CI -10.58 to -5.59), -10.03 (-12.52 to -7.55), -12.96 (-15.46 to -10.46) and -14.13 (-16.67 to -11.59), all P<0.0001.

The posted analysis (a mixed model for repeated measures) excludes weight measurements after permanent treatment discontinuation, non-compliance, or lifestyle change such as other weight-loss drugs. It is a treatment-adherent, efficacy-type result and not an intent-to-treat result. No intent-to-treat figure for berobenatide was found.

These are registry-posted results with no peer-reviewed paper. A PubMed search on 10 October 2026 for berobenatide OR MET097 OR MET-097 OR MET-097i OR PF-08653944 OR PF'3944 returned 0 records, so no peer-reviewed report of any berobenatide trial was found.

VESPER-1 registry results: 239 adults, 28 weeks, treatment-adherent, no paper

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT06712836 (VESPER-1), results posted by the sponsor. Read on 10 October 2026.

Least-squares mean percent change in body weight at week 28 was +1.67 (SE 0.90) on placebo and -6.41, -8.36, -11.29 and -12.45 on 0.4, 0.6, 0.9 and 1.2 mg weekly. Differences versus placebo were -8.09 (95% CI -10.58 to -5.59), -10.03 (-12.52 to -7.55), -12.96 (-15.46 to -10.46) and -14.13 (-16.67 to -11.59), all P<0.0001. The posted analysis (mixed model for repeated measures) excludes weight measurements after permanent treatment discontinuation, non-compliance, or lifestyle change such as other weight-loss drugs, so it is a treatment-adherent, efficacy-type result and not an intent-to-treat result. Adverse events at or above the 5% reporting threshold (placebo versus 0.4, 0.6, 0.9 and 1.2 mg): nausea 13/48 versus 15/48, 17/48, 16/47 and 24/48; vomiting 6/48 versus 11/48, 8/48, 13/47 and 12/48; diarrhea 5/48 versus 8/48, 5/48, 6/47 and 11/48; dyspepsia 1/48 versus 7/48, 5/48, 7/47 and 7/48. Serious adverse events were reported in 3 participants on active drug and none on placebo: obstructive pancreatitis (0.4 mg), perforated appendicitis (0.4 mg) and alcohol poisoning (0.6 mg). Gastrointestinal events rose with dose, in line with the GLP-1 class.

Participants / model
239 adults with obesity or overweight at US sites (eligibility age 18 to 70; placebo 48, 0.4 mg 48, 0.6 mg 48, 0.9 mg 47, 1.2 mg 48)
Treatment
Weekly subcutaneous berobenatide (MET097) 0.4, 0.6, 0.9 or 1.2 mg, or placebo
Follow-up
28 weeks
Study design
Phase 2b randomized, double-blind, placebo-controlled trial; results posted by the sponsor with no peer-reviewed paper
Funding
Results posted by the sponsor on ClinicalTrials.gov; the record is from the Metsera era.

The weekly figures are least-squares mean changes from baseline, and the differences versus placebo are placebo-adjusted. The analysis is treatment-adherent, so no intent-to-treat figure for berobenatide was found.

Read the original source
PubMed search, 10 October 2026: 0 records, no peer-reviewed berobenatide report

PubMed search record

PubMed search for berobenatide OR MET097 OR MET-097 OR MET-097i OR PF-08653944 OR PF'3944, run on 10 October 2026 (0 records).

The search returned 0 records. In the records reviewed there is no peer-reviewed report of any berobenatide trial. Its efficacy evidence is one set of registry-posted phase 2b results and Pfizer company statements.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Search run on 10 October 2026
Study design
Literature search
Funding
not stated in the source

A search result shows what the database returned on that date. It is not proof that no unindexed study exists.

Read the original source

What has Pfizer reported that no paper or registry record shows?

Pfizer reported on 3 February 2026 placebo-adjusted weight loss of up to 12.3% (efficacy estimand) in VESPER-3 with monthly dosing, and on 5 June 2026 a 15.9% weight loss that is not placebo-adjusted in an exploratory extension. Both are company statements and are not peer reviewed.

On 3 February 2026 Pfizer reported topline results from VESPER-3 (NCT06973720), a phase 2b trial of 64 weeks in 268 adults enrolled, with obesity or overweight and without type 2 diabetes. No results are posted on the registry. After 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% by the efficacy estimand, and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). The detailed results were due at the American Diabetes Association meeting in June 2026 and were not retrieved, so only Pfizer's topline text is used.

On 5 June 2026 Pfizer reported a 32-week exploratory extension (Part B) of VESPER-1. It showed a weight loss of 15.9% with no plateau at 32 weeks (week 60 of the study) in participants who escalated from placebo to 2.4 mg weekly. This figure is not placebo-adjusted and comes from an exploratory part, so it should not be set beside the 12.3% placebo-adjusted VESPER-3 figure. The estimand is not stated in the sources reviewed. In VESPER-2, in adults with type 2 diabetes, Pfizer reported that HbA1c fell 2.2% on 1.6 mg weekly at week 28 versus 0.2% on placebo (on-treatment estimand).

Pfizer mentions 2.4 mg and 9.6 mg doses for phase 3. The records reviewed give no efficacy or safety data for them beyond the 15.9% extension figure.

Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source
Company statement, 5 June 2026: 15.9% not placebo-adjusted, VESPER-2 HbA1c, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 5 June 2026 (date from the BusinessWire release URL) on phase 2b efficacy and tolerability supporting monthly dosing of berobenatide.

A 32-week exploratory extension (Part B) of VESPER-1 showed a non-placebo-adjusted weight loss of 15.9% with no plateau at 32 weeks (week 60 of the study) in participants who escalated from placebo to 2.4 mg weekly. In VESPER-2 (adults with type 2 diabetes) HbA1c fell 2.2% on 1.6 mg weekly at week 28 versus 0.2% on placebo (on-treatment estimand). The 15.9% is not placebo-adjusted and comes from an exploratory part, so it should not be set beside the 12.3% placebo-adjusted VESPER-3 figure.

Participants / model
Adults with obesity or overweight, with and without type 2 diabetes
Treatment
Weekly subcutaneous berobenatide up to 2.4 mg
Follow-up
Weight loss at week 60 of the study; HbA1c at week 28
Study design
Company press release on an exploratory extension and a type 2 diabetes trial; not peer reviewed
Funding
not stated in the source

The estimand for the 15.9% is not stated in the sources reviewed. The 2.4 mg and 9.6 mg doses are mentioned by Pfizer for phase 3, with no efficacy or safety data beyond the 15.9% figure.

Read the original source

Is phase 3 under way, and does it have results?

Phase 3 has started and has no results. A ClinicalTrials.gov search on 10 October 2026 returned 18 records, 8 of them phase 3, including VESPER-4 (3,578 adults enrolled, once weekly), VESPER-5 (1,078 enrolled, with type 2 diabetes) and VESPER-6 (once monthly, recruiting an estimated 954). None has posted results.

A ClinicalTrials.gov search on 10 October 2026 for berobenatide, MET097, MET-097, MET-097i and PF-08653944 returned 18 records: 8 phase 3 registrations, 4 phase 2, 2 phase 1/2 and 4 phase 1.

VESPER-4 (NCT07311850, once weekly, adults without diabetes) started on 19 December 2025, has 3,578 participants enrolled, is Active, not recruiting, has a week 64 primary endpoint and an estimated primary completion of 21 September 2027. VESPER-5 (NCT07400653, adults with type 2 diabetes) has 1,078 enrolled and is Active, not recruiting. VESPER-6 (NCT07595549, once monthly) started on 10 June 2026 and is recruiting an estimated 954 participants. None has posted results. Registrations without posted results are not outcomes.

Registry search, 10 October 2026: 8 phase 3 records, none with posted results

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07311850 (VESPER-4), with NCT07400653 (VESPER-5) and NCT07595549 (VESPER-6). Search for berobenatide, MET097, MET-097, MET-097i and PF-08653944 run on 10 October 2026.

The search returned 18 records, 8 of them phase 3 registrations (4 phase 2, 2 phase 1/2 and 4 phase 1 make up the rest). VESPER-4 (NCT07311850, once weekly, adults without diabetes) started on 19 December 2025, has 3,578 participants enrolled, is Active, not recruiting, with a week 64 primary endpoint and estimated primary completion on 21 September 2027. VESPER-5 (NCT07400653, with type 2 diabetes) has 1,078 enrolled and is Active, not recruiting. VESPER-6 (NCT07595549, once monthly) started on 10 June 2026 and is recruiting an estimated 954. None has posted results. Registrations without posted results are not outcomes.

Participants / model
Adults with obesity or overweight, without and with type 2 diabetes
Treatment
Subcutaneous berobenatide, weekly and monthly
Follow-up
Week 64 primary endpoint in VESPER-4; estimated primary completion 21 September 2027
Study design
Registered phase 3 design and status only
Funding
not stated in the source

Registry design and status only. No efficacy or safety result from any phase 3 trial is public.

Read the original source

Is berobenatide a monthly, ultra-long-acting GLP-1 in phase 2b heading into pivotal trials?

Partly out of date. Berobenatide, MET-097i and PF-08653944 are one molecule that Pfizer acquired with Metsera, and Pfizer calls it an ultra-long-acting GLP-1 receptor agonist. But phase 3 began in December 2025, so it is no longer heading into pivotal trials, and none has results.

The claim is that berobenatide and MET-097 (Pfizer, through the Metsera acquisition) are a monthly or ultra-long-acting GLP-1 in phase 2b heading into pivotal trials, with unclear naming. The naming question is settled by the registry records and Pfizer's press release: berobenatide, MET-097i and PF-08653944 are one molecule, and Pfizer acquired it with Metsera. Pfizer describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist, and monthly regimens appear in company statements and in the registered phase 3 trial VESPER-6.

The stage is out of date. Phase 3 began with VESPER-4 on 19 December 2025, and a search on 10 October 2026 found 8 phase 3 registrations, none with posted results. The efficacy evidence remains one set of registry-posted phase 2b results (VESPER-1, treatment-adherent analysis) and Pfizer company statements, with no peer-reviewed paper.

Registry records: Berobenatide, MET-097i, MET097 and PF-08653944 as one molecule

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07823608, with records NCT07311850 (VESPER-4), NCT07400653 (VESPER-5) and NCT06712836 (VESPER-1). Read on 10 October 2026.

The Pfizer-sponsored record NCT07823608 lists the intervention Berobenatide with other names MET-097i and PF-08653944. Pfizer's VESPER-4 record NCT07311850 lists MET097 with other name PF-08653944, and its VESPER-5 record NCT07400653 lists PF-08653944 with other name MET097. The results posted on the Metsera-era phase 2b record NCT06712836 label the arms Berobenatide. MET-097i is the injectable; no primary record on any oral Metsera MET-097 product was retrieved and none is covered here.

Participants / model
Sponsor and code identity, not a clinical population
Treatment
Subcutaneous injection
Follow-up
Not applicable
Study design
Trial registry records
Funding
Sponsor: Pfizer

Berobenatide, MET-097i, MET097 and PF-08653944 are treated as one molecule on this page.

Read the original source
Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source
Registry search, 10 October 2026: 8 phase 3 records, none with posted results

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07311850 (VESPER-4), with NCT07400653 (VESPER-5) and NCT07595549 (VESPER-6). Search for berobenatide, MET097, MET-097, MET-097i and PF-08653944 run on 10 October 2026.

The search returned 18 records, 8 of them phase 3 registrations (4 phase 2, 2 phase 1/2 and 4 phase 1 make up the rest). VESPER-4 (NCT07311850, once weekly, adults without diabetes) started on 19 December 2025, has 3,578 participants enrolled, is Active, not recruiting, with a week 64 primary endpoint and estimated primary completion on 21 September 2027. VESPER-5 (NCT07400653, with type 2 diabetes) has 1,078 enrolled and is Active, not recruiting. VESPER-6 (NCT07595549, once monthly) started on 10 June 2026 and is recruiting an estimated 954. None has posted results. Registrations without posted results are not outcomes.

Participants / model
Adults with obesity or overweight, without and with type 2 diabetes
Treatment
Subcutaneous berobenatide, weekly and monthly
Follow-up
Week 64 primary endpoint in VESPER-4; estimated primary completion 21 September 2027
Study design
Registered phase 3 design and status only
Funding
not stated in the source

Registry design and status only. No efficacy or safety result from any phase 3 trial is public.

Read the original source
VESPER-1 registry results: 239 adults, 28 weeks, treatment-adherent, no paper

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT06712836 (VESPER-1), results posted by the sponsor. Read on 10 October 2026.

Least-squares mean percent change in body weight at week 28 was +1.67 (SE 0.90) on placebo and -6.41, -8.36, -11.29 and -12.45 on 0.4, 0.6, 0.9 and 1.2 mg weekly. Differences versus placebo were -8.09 (95% CI -10.58 to -5.59), -10.03 (-12.52 to -7.55), -12.96 (-15.46 to -10.46) and -14.13 (-16.67 to -11.59), all P<0.0001. The posted analysis (mixed model for repeated measures) excludes weight measurements after permanent treatment discontinuation, non-compliance, or lifestyle change such as other weight-loss drugs, so it is a treatment-adherent, efficacy-type result and not an intent-to-treat result. Adverse events at or above the 5% reporting threshold (placebo versus 0.4, 0.6, 0.9 and 1.2 mg): nausea 13/48 versus 15/48, 17/48, 16/47 and 24/48; vomiting 6/48 versus 11/48, 8/48, 13/47 and 12/48; diarrhea 5/48 versus 8/48, 5/48, 6/47 and 11/48; dyspepsia 1/48 versus 7/48, 5/48, 7/47 and 7/48. Serious adverse events were reported in 3 participants on active drug and none on placebo: obstructive pancreatitis (0.4 mg), perforated appendicitis (0.4 mg) and alcohol poisoning (0.6 mg). Gastrointestinal events rose with dose, in line with the GLP-1 class.

Participants / model
239 adults with obesity or overweight at US sites (eligibility age 18 to 70; placebo 48, 0.4 mg 48, 0.6 mg 48, 0.9 mg 47, 1.2 mg 48)
Treatment
Weekly subcutaneous berobenatide (MET097) 0.4, 0.6, 0.9 or 1.2 mg, or placebo
Follow-up
28 weeks
Study design
Phase 2b randomized, double-blind, placebo-controlled trial; results posted by the sponsor with no peer-reviewed paper
Funding
Results posted by the sponsor on ClinicalTrials.gov; the record is from the Metsera era.

The weekly figures are least-squares mean changes from baseline, and the differences versus placebo are placebo-adjusted. The analysis is treatment-adherent, so no intent-to-treat figure for berobenatide was found.

Read the original source
PubMed search, 10 October 2026: 0 records, no peer-reviewed berobenatide report

PubMed search record

PubMed search for berobenatide OR MET097 OR MET-097 OR MET-097i OR PF-08653944 OR PF'3944, run on 10 October 2026 (0 records).

The search returned 0 records. In the records reviewed there is no peer-reviewed report of any berobenatide trial. Its efficacy evidence is one set of registry-posted phase 2b results and Pfizer company statements.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Search run on 10 October 2026
Study design
Literature search
Funding
not stated in the source

A search result shows what the database returned on that date. It is not proof that no unindexed study exists.

Read the original source

How does berobenatide work, and is its half-life known?

Berobenatide is a GLP-1 receptor agonist: an exendin-4 derivative carrying a fatty-diacid group. Pfizer calls it ultra-long-acting and fully biased. The sources reviewed give no half-life or other pharmacokinetic value.

The WHO record defines berobenatide as an exendin-4 derivative carrying a 19-carboxynonadecanoyl-glutamyl-lysine fatty-diacid group, with the stated action GLP-1 receptor agonist. Pfizer's press release of 3 February 2026 describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. The sources reviewed give no signaling, receptor-binding or animal data, so nothing further about the mechanism is stated.

No half-life, Tmax or other pharmacokinetic value was found in the records reviewed, so none is entered. Weekly dosing was used in VESPER-1 and VESPER-4, and monthly regimens in VESPER-3 and VESPER-6. These are study designs, not measured half-lives.

WHO Proposed INN List 133 (2025): exendin-4 derivative, GLP-1 receptor agonist

Chemical identity record

World Health Organization. Proposed International Nonproprietary Names: List 133. WHO Drug Information, Vol. 39, No. 2, 2025.

Berobenatide is defined as an exendin-4 derivative carrying a 19-carboxynonadecanoyl-glutamyl-lysine fatty-diacid group, with the stated action GLP-1 receptor agonist. The entry lists the formula C232H369N57O68 and CAS 3028974-74-2. WHO INN entries carry no company codes. A PubChem name search for berobenatide, MET-097 and MET-097i returned no compound record on 10 October 2026.

Participants / model
Molecular identity, not a clinical population
Treatment
Peptide, subcutaneous
Follow-up
Not applicable
Study design
Official WHO nomenclature record (Proposed INN list)
Funding
not stated in the source

The link between the INN and the company codes rests on the sponsor-registered other names and Pfizer's press release, because the WHO list carries no codes.

Read the original source
Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source

What adverse events were reported?

In VESPER-1, gastrointestinal events rose with dose: nausea in 24 of 48 on 1.2 mg versus 13 of 48 on placebo. Serious adverse events occurred in 3 participants on active drug (obstructive pancreatitis, perforated appendicitis, alcohol poisoning) and none on placebo.

The sponsor-posted VESPER-1 results list adverse events at or above the 5% reporting threshold. For placebo versus 0.4, 0.6, 0.9 and 1.2 mg, nausea was 13 of 48 versus 15 of 48, 17 of 48, 16 of 47 and 24 of 48. Vomiting was 6 of 48 versus 11 of 48, 8 of 48, 13 of 47 and 12 of 48. Diarrhea was 5 of 48 versus 8 of 48, 5 of 48, 6 of 47 and 11 of 48. Dyspepsia was 1 of 48 versus 7 of 48, 5 of 48, 7 of 47 and 7 of 48. Gastrointestinal events rose with dose, in line with the GLP-1 class.

Serious adverse events were reported in 3 participants on active drug and none on placebo: obstructive pancreatitis (0.4 mg), perforated appendicitis (0.4 mg) and alcohol poisoning (0.6 mg).

Pfizer's 3 February 2026 statement on VESPER-3 says that across Arms 1 and 3 five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo, and that no more than one instance of severe nausea or vomiting occurred in any dose group. This is a company statement with no results posted on the registry. No peer-reviewed safety report exists, and no phase 3 safety data are public.

VESPER-1 registry results: 239 adults, 28 weeks, treatment-adherent, no paper

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT06712836 (VESPER-1), results posted by the sponsor. Read on 10 October 2026.

Least-squares mean percent change in body weight at week 28 was +1.67 (SE 0.90) on placebo and -6.41, -8.36, -11.29 and -12.45 on 0.4, 0.6, 0.9 and 1.2 mg weekly. Differences versus placebo were -8.09 (95% CI -10.58 to -5.59), -10.03 (-12.52 to -7.55), -12.96 (-15.46 to -10.46) and -14.13 (-16.67 to -11.59), all P<0.0001. The posted analysis (mixed model for repeated measures) excludes weight measurements after permanent treatment discontinuation, non-compliance, or lifestyle change such as other weight-loss drugs, so it is a treatment-adherent, efficacy-type result and not an intent-to-treat result. Adverse events at or above the 5% reporting threshold (placebo versus 0.4, 0.6, 0.9 and 1.2 mg): nausea 13/48 versus 15/48, 17/48, 16/47 and 24/48; vomiting 6/48 versus 11/48, 8/48, 13/47 and 12/48; diarrhea 5/48 versus 8/48, 5/48, 6/47 and 11/48; dyspepsia 1/48 versus 7/48, 5/48, 7/47 and 7/48. Serious adverse events were reported in 3 participants on active drug and none on placebo: obstructive pancreatitis (0.4 mg), perforated appendicitis (0.4 mg) and alcohol poisoning (0.6 mg). Gastrointestinal events rose with dose, in line with the GLP-1 class.

Participants / model
239 adults with obesity or overweight at US sites (eligibility age 18 to 70; placebo 48, 0.4 mg 48, 0.6 mg 48, 0.9 mg 47, 1.2 mg 48)
Treatment
Weekly subcutaneous berobenatide (MET097) 0.4, 0.6, 0.9 or 1.2 mg, or placebo
Follow-up
28 weeks
Study design
Phase 2b randomized, double-blind, placebo-controlled trial; results posted by the sponsor with no peer-reviewed paper
Funding
Results posted by the sponsor on ClinicalTrials.gov; the record is from the Metsera era.

The weekly figures are least-squares mean changes from baseline, and the differences versus placebo are placebo-adjusted. The analysis is treatment-adherent, so no intent-to-treat figure for berobenatide was found.

Read the original source
Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source

Why does berobenatide sit in C tier?

Its efficacy evidence is one set of sponsor-posted phase 2b results from a treatment-adherent analysis, plus Pfizer company statements. There is no peer-reviewed paper, and the phase 3 trials have not reported.

Berobenatide has registry-posted results from 239 adults over 28 weeks (-12.45% at 1.2 mg weekly against +1.67% on placebo, a placebo-adjusted difference of -14.13%), analyzed treatment-adherently, and company statements for the monthly regimen. There is no peer-reviewed paper, and no intent-to-treat figure was found.

The phase 3 program is large (8 registrations, 3,578 enrolled in VESPER-4 alone), but none of it has results, and no regulatory approval was found. The name question is settled: berobenatide, MET-097i and PF-08653944 are one molecule.

VESPER-1 registry results: 239 adults, 28 weeks, treatment-adherent, no paper

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT06712836 (VESPER-1), results posted by the sponsor. Read on 10 October 2026.

Least-squares mean percent change in body weight at week 28 was +1.67 (SE 0.90) on placebo and -6.41, -8.36, -11.29 and -12.45 on 0.4, 0.6, 0.9 and 1.2 mg weekly. Differences versus placebo were -8.09 (95% CI -10.58 to -5.59), -10.03 (-12.52 to -7.55), -12.96 (-15.46 to -10.46) and -14.13 (-16.67 to -11.59), all P<0.0001. The posted analysis (mixed model for repeated measures) excludes weight measurements after permanent treatment discontinuation, non-compliance, or lifestyle change such as other weight-loss drugs, so it is a treatment-adherent, efficacy-type result and not an intent-to-treat result. Adverse events at or above the 5% reporting threshold (placebo versus 0.4, 0.6, 0.9 and 1.2 mg): nausea 13/48 versus 15/48, 17/48, 16/47 and 24/48; vomiting 6/48 versus 11/48, 8/48, 13/47 and 12/48; diarrhea 5/48 versus 8/48, 5/48, 6/47 and 11/48; dyspepsia 1/48 versus 7/48, 5/48, 7/47 and 7/48. Serious adverse events were reported in 3 participants on active drug and none on placebo: obstructive pancreatitis (0.4 mg), perforated appendicitis (0.4 mg) and alcohol poisoning (0.6 mg). Gastrointestinal events rose with dose, in line with the GLP-1 class.

Participants / model
239 adults with obesity or overweight at US sites (eligibility age 18 to 70; placebo 48, 0.4 mg 48, 0.6 mg 48, 0.9 mg 47, 1.2 mg 48)
Treatment
Weekly subcutaneous berobenatide (MET097) 0.4, 0.6, 0.9 or 1.2 mg, or placebo
Follow-up
28 weeks
Study design
Phase 2b randomized, double-blind, placebo-controlled trial; results posted by the sponsor with no peer-reviewed paper
Funding
Results posted by the sponsor on ClinicalTrials.gov; the record is from the Metsera era.

The weekly figures are least-squares mean changes from baseline, and the differences versus placebo are placebo-adjusted. The analysis is treatment-adherent, so no intent-to-treat figure for berobenatide was found.

Read the original source
Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source
Registry search, 10 October 2026: 8 phase 3 records, none with posted results

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07311850 (VESPER-4), with NCT07400653 (VESPER-5) and NCT07595549 (VESPER-6). Search for berobenatide, MET097, MET-097, MET-097i and PF-08653944 run on 10 October 2026.

The search returned 18 records, 8 of them phase 3 registrations (4 phase 2, 2 phase 1/2 and 4 phase 1 make up the rest). VESPER-4 (NCT07311850, once weekly, adults without diabetes) started on 19 December 2025, has 3,578 participants enrolled, is Active, not recruiting, with a week 64 primary endpoint and estimated primary completion on 21 September 2027. VESPER-5 (NCT07400653, with type 2 diabetes) has 1,078 enrolled and is Active, not recruiting. VESPER-6 (NCT07595549, once monthly) started on 10 June 2026 and is recruiting an estimated 954. None has posted results. Registrations without posted results are not outcomes.

Participants / model
Adults with obesity or overweight, without and with type 2 diabetes
Treatment
Subcutaneous berobenatide, weekly and monthly
Follow-up
Week 64 primary endpoint in VESPER-4; estimated primary completion 21 September 2027
Study design
Registered phase 3 design and status only
Funding
not stated in the source

Registry design and status only. No efficacy or safety result from any phase 3 trial is public.

Read the original source
Company filing, 13 November 2025: Metsera acquisition; no approval found

Regulatory record

Pfizer Inc. Form 8-K dated 13 November 2025, U.S. Securities and Exchange Commission. openFDA Drugs@FDA and DailyMed searches run on 10 October 2026.

Pfizer completed its acquisition of Metsera, Inc. on 13 November 2025 at $65.60 per share in cash (enterprise value about $7.0 billion) plus a contingent value right of up to $20.65 per share, which includes $6.40 payable on FDA approval of monthly MET-097i monotherapy. No regulatory approval was found: on 10 October 2026 openFDA Drugs@FDA returned no application records for berobenatide and a DailyMed search returned no labels. The contingent value right tied to a future FDA approval shows none had occurred by 13 November 2025.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Filing dated 13 November 2025; searches run on 10 October 2026
Study design
Company filing; US regulator database searches
Funding
not stated in the source

A search result shows what the databases held on that date. Pfizer is the developer through the Metsera acquisition.

Read the original source
PubMed search, 10 October 2026: 0 records, no peer-reviewed berobenatide report

PubMed search record

PubMed search for berobenatide OR MET097 OR MET-097 OR MET-097i OR PF-08653944 OR PF'3944, run on 10 October 2026 (0 records).

The search returned 0 records. In the records reviewed there is no peer-reviewed report of any berobenatide trial. Its efficacy evidence is one set of registry-posted phase 2b results and Pfizer company statements.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Search run on 10 October 2026
Study design
Literature search
Funding
not stated in the source

A search result shows what the database returned on that date. It is not proof that no unindexed study exists.

Read the original source

Studies and sources

WHO Proposed INN List 133 (2025): exendin-4 derivative, GLP-1 receptor agonist

Chemical identity record

World Health Organization. Proposed International Nonproprietary Names: List 133. WHO Drug Information, Vol. 39, No. 2, 2025.

Berobenatide is defined as an exendin-4 derivative carrying a 19-carboxynonadecanoyl-glutamyl-lysine fatty-diacid group, with the stated action GLP-1 receptor agonist. The entry lists the formula C232H369N57O68 and CAS 3028974-74-2. WHO INN entries carry no company codes. A PubChem name search for berobenatide, MET-097 and MET-097i returned no compound record on 10 October 2026.

Participants / model
Molecular identity, not a clinical population
Treatment
Peptide, subcutaneous
Follow-up
Not applicable
Study design
Official WHO nomenclature record (Proposed INN list)
Funding
not stated in the source

The link between the INN and the company codes rests on the sponsor-registered other names and Pfizer's press release, because the WHO list carries no codes.

Read the original source
Registry records: Berobenatide, MET-097i, MET097 and PF-08653944 as one molecule

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07823608, with records NCT07311850 (VESPER-4), NCT07400653 (VESPER-5) and NCT06712836 (VESPER-1). Read on 10 October 2026.

The Pfizer-sponsored record NCT07823608 lists the intervention Berobenatide with other names MET-097i and PF-08653944. Pfizer's VESPER-4 record NCT07311850 lists MET097 with other name PF-08653944, and its VESPER-5 record NCT07400653 lists PF-08653944 with other name MET097. The results posted on the Metsera-era phase 2b record NCT06712836 label the arms Berobenatide. MET-097i is the injectable; no primary record on any oral Metsera MET-097 product was retrieved and none is covered here.

Participants / model
Sponsor and code identity, not a clinical population
Treatment
Subcutaneous injection
Follow-up
Not applicable
Study design
Trial registry records
Funding
Sponsor: Pfizer

Berobenatide, MET-097i, MET097 and PF-08653944 are treated as one molecule on this page.

Read the original source
Company statement, 3 February 2026: VESPER-3, placebo-adjusted up to 12.3%, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 3 February 2026 on the VESPER-3 phase 2b results for the ultra-long-acting injectable GLP-1 receptor agonist PF-08653944.

The release states PF-08653944 (PF'3944; previously called MET-097i) and describes it as an ultra-long-acting, fully biased GLP-1 receptor agonist. In VESPER-3 (NCT06973720, phase 2b, 64 weeks, 268 adults enrolled, no results posted on the registry), after 12 weekly doses followed by monthly dosing to week 28, placebo-adjusted weight loss was up to 12.3% (efficacy estimand), and 10% and 12.3% in Arms 1 and 3, the low and medium monthly regimens planned for phase 3. The primary endpoint was superior to placebo in all four regimens (P<0.001). Across Arms 1 and 3, five participants stopped treatment for adverse events in the weekly phase and five in the monthly phase, versus none on placebo. Pfizer reports no more than one instance of severe nausea or vomiting in any dose group. The detailed results were due at the American Diabetes Association meeting in June 2026.

Participants / model
268 adults enrolled with obesity or overweight, without type 2 diabetes
Treatment
Weekly titration to monthly subcutaneous berobenatide
Follow-up
64 weeks; weight loss at week 28
Study design
Company press release on a phase 2b trial; not peer reviewed
Funding
not stated in the source

Placebo-adjusted weight loss by the efficacy estimand, a company statement. The detailed week 28 results from the June 2026 meeting were not retrieved, so only Pfizer's topline text is used.

Read the original source
Company filing, 13 November 2025: Metsera acquisition; no approval found

Regulatory record

Pfizer Inc. Form 8-K dated 13 November 2025, U.S. Securities and Exchange Commission. openFDA Drugs@FDA and DailyMed searches run on 10 October 2026.

Pfizer completed its acquisition of Metsera, Inc. on 13 November 2025 at $65.60 per share in cash (enterprise value about $7.0 billion) plus a contingent value right of up to $20.65 per share, which includes $6.40 payable on FDA approval of monthly MET-097i monotherapy. No regulatory approval was found: on 10 October 2026 openFDA Drugs@FDA returned no application records for berobenatide and a DailyMed search returned no labels. The contingent value right tied to a future FDA approval shows none had occurred by 13 November 2025.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Filing dated 13 November 2025; searches run on 10 October 2026
Study design
Company filing; US regulator database searches
Funding
not stated in the source

A search result shows what the databases held on that date. Pfizer is the developer through the Metsera acquisition.

Read the original source
VESPER-1 registry results: 239 adults, 28 weeks, treatment-adherent, no paper

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT06712836 (VESPER-1), results posted by the sponsor. Read on 10 October 2026.

Least-squares mean percent change in body weight at week 28 was +1.67 (SE 0.90) on placebo and -6.41, -8.36, -11.29 and -12.45 on 0.4, 0.6, 0.9 and 1.2 mg weekly. Differences versus placebo were -8.09 (95% CI -10.58 to -5.59), -10.03 (-12.52 to -7.55), -12.96 (-15.46 to -10.46) and -14.13 (-16.67 to -11.59), all P<0.0001. The posted analysis (mixed model for repeated measures) excludes weight measurements after permanent treatment discontinuation, non-compliance, or lifestyle change such as other weight-loss drugs, so it is a treatment-adherent, efficacy-type result and not an intent-to-treat result. Adverse events at or above the 5% reporting threshold (placebo versus 0.4, 0.6, 0.9 and 1.2 mg): nausea 13/48 versus 15/48, 17/48, 16/47 and 24/48; vomiting 6/48 versus 11/48, 8/48, 13/47 and 12/48; diarrhea 5/48 versus 8/48, 5/48, 6/47 and 11/48; dyspepsia 1/48 versus 7/48, 5/48, 7/47 and 7/48. Serious adverse events were reported in 3 participants on active drug and none on placebo: obstructive pancreatitis (0.4 mg), perforated appendicitis (0.4 mg) and alcohol poisoning (0.6 mg). Gastrointestinal events rose with dose, in line with the GLP-1 class.

Participants / model
239 adults with obesity or overweight at US sites (eligibility age 18 to 70; placebo 48, 0.4 mg 48, 0.6 mg 48, 0.9 mg 47, 1.2 mg 48)
Treatment
Weekly subcutaneous berobenatide (MET097) 0.4, 0.6, 0.9 or 1.2 mg, or placebo
Follow-up
28 weeks
Study design
Phase 2b randomized, double-blind, placebo-controlled trial; results posted by the sponsor with no peer-reviewed paper
Funding
Results posted by the sponsor on ClinicalTrials.gov; the record is from the Metsera era.

The weekly figures are least-squares mean changes from baseline, and the differences versus placebo are placebo-adjusted. The analysis is treatment-adherent, so no intent-to-treat figure for berobenatide was found.

Read the original source
Company statement, 5 June 2026: 15.9% not placebo-adjusted, VESPER-2 HbA1c, not peer reviewed

Regulatory record

Pfizer Inc. press release dated 5 June 2026 (date from the BusinessWire release URL) on phase 2b efficacy and tolerability supporting monthly dosing of berobenatide.

A 32-week exploratory extension (Part B) of VESPER-1 showed a non-placebo-adjusted weight loss of 15.9% with no plateau at 32 weeks (week 60 of the study) in participants who escalated from placebo to 2.4 mg weekly. In VESPER-2 (adults with type 2 diabetes) HbA1c fell 2.2% on 1.6 mg weekly at week 28 versus 0.2% on placebo (on-treatment estimand). The 15.9% is not placebo-adjusted and comes from an exploratory part, so it should not be set beside the 12.3% placebo-adjusted VESPER-3 figure.

Participants / model
Adults with obesity or overweight, with and without type 2 diabetes
Treatment
Weekly subcutaneous berobenatide up to 2.4 mg
Follow-up
Weight loss at week 60 of the study; HbA1c at week 28
Study design
Company press release on an exploratory extension and a type 2 diabetes trial; not peer reviewed
Funding
not stated in the source

The estimand for the 15.9% is not stated in the sources reviewed. The 2.4 mg and 9.6 mg doses are mentioned by Pfizer for phase 3, with no efficacy or safety data beyond the 15.9% figure.

Read the original source
Registry search, 10 October 2026: 8 phase 3 records, none with posted results

Trial registry record

ClinicalTrials.gov, U.S. National Library of Medicine. Record NCT07311850 (VESPER-4), with NCT07400653 (VESPER-5) and NCT07595549 (VESPER-6). Search for berobenatide, MET097, MET-097, MET-097i and PF-08653944 run on 10 October 2026.

The search returned 18 records, 8 of them phase 3 registrations (4 phase 2, 2 phase 1/2 and 4 phase 1 make up the rest). VESPER-4 (NCT07311850, once weekly, adults without diabetes) started on 19 December 2025, has 3,578 participants enrolled, is Active, not recruiting, with a week 64 primary endpoint and estimated primary completion on 21 September 2027. VESPER-5 (NCT07400653, with type 2 diabetes) has 1,078 enrolled and is Active, not recruiting. VESPER-6 (NCT07595549, once monthly) started on 10 June 2026 and is recruiting an estimated 954. None has posted results. Registrations without posted results are not outcomes.

Participants / model
Adults with obesity or overweight, without and with type 2 diabetes
Treatment
Subcutaneous berobenatide, weekly and monthly
Follow-up
Week 64 primary endpoint in VESPER-4; estimated primary completion 21 September 2027
Study design
Registered phase 3 design and status only
Funding
not stated in the source

Registry design and status only. No efficacy or safety result from any phase 3 trial is public.

Read the original source
PubMed search, 10 October 2026: 0 records, no peer-reviewed berobenatide report

PubMed search record

PubMed search for berobenatide OR MET097 OR MET-097 OR MET-097i OR PF-08653944 OR PF'3944, run on 10 October 2026 (0 records).

The search returned 0 records. In the records reviewed there is no peer-reviewed report of any berobenatide trial. Its efficacy evidence is one set of registry-posted phase 2b results and Pfizer company statements.

Participants / model
Records returned, not a population
Treatment
Not applicable
Follow-up
Search run on 10 October 2026
Study design
Literature search
Funding
not stated in the source

A search result shows what the database returned on that date. It is not proof that no unindexed study exists.

Read the original source

Why is Berobenatide in C tier?

C fits a compound whose efficacy evidence is one set of sponsor-posted phase 2b results from a treatment-adherent analysis plus company statements, with no peer-reviewed paper. The weekly result is large (-14.13% versus placebo at 1.2 mg), but no intent-to-treat figure was found, the phase 3 trials have not reported, and no regulator has approved the compound.