MET-233

updated

MET-233 (written MET-233i by Metsera) is an unapproved amylin analog now owned by Pfizer through its 13 November 2025 acquisition of Metsera. The only efficacy data are two company-reported phase 1 parts of 40 participants each, with cohorts of 6 to 8 per dose and no peer-reviewed report. A combination with MET-097i is the stated plan, and no structure, INN or FDA record is public.

Amylin analog (ultra-long-acting, injectable)

  • Pfizer acquired Metsera on 13 November 2025, and its 10-Q for the quarter ended 28 June 2026 calls MET-233i an amylin analog and ties contingent value right payments to a MET-097i plus MET-233i combination.
  • In a Metsera 8-K dated 9 June 2025, the company reported a mean placebo-subtracted weight loss of 5.3% at day 8 after a single 2.4 mg dose (6 participants) and 8.4% at day 36 after five weekly 1.2 mg doses (8 participants).
  • Nausea occurred in 6 of 6 participants after a single 2.4 mg dose and in 8 of 8 after five weekly 1.2 mg doses, with no placebo participant affected in the single dose part.
  • PubMed queries on 10 October 2026 found no peer-reviewed report of MET-233i trial data. One review table repeats the company's figures and adds no independent data.
  • The larger phase 1 (NCT07022977, 144 participants, completed 21 April 2026) and the combination phase 1/2 (NCT06924320, 381 estimated) are registered with no posted results.
  • No structure, INN, PubChem record or FDA application is public, and the Pfizer code PF-08653945 is not confirmed to be this compound.

What is MET-233, and is it approved?

MET-233 (written MET-233i by Metsera) is an investigational amylin analog developed by Metsera and now owned by Pfizer, which acquired Metsera on 13 November 2025. FDA database searches on 10 October 2026 found no application or label, and no structure or INN is public.

The compound is written MET-233i by Metsera and MET233 in ClinicalTrials.gov records. Metsera's 8-K exhibit of 29 September 2025 calls it an ultra-long acting monthly amylin analog candidate. PubChem returned no record for MET-233i or MET233i on 10 October 2026, so no structure, formula or molecular weight is public in the records reviewed. The sources give no INN, and the WHO proposed INN lists 126 to 135, which print no development codes, contain amylin-class names that could not be tied to MET-233i.

Pfizer's Form 10-Q for the quarter ended 28 June 2026 says Pfizer acquired Metsera on 13 November 2025 for $65.60 per share in cash plus a contingent value right of up to $20.65 per share. The CVR pays $4.60 after the phase 3 trial start of the MET-097i plus MET-233i combination, $6.40 after FDA approval of monthly MET-097i monotherapy and $9.65 after FDA approval of the monthly MET-097i plus MET-233i combination. The filing calls MET-233i an amylin analog, and ClinicalTrials.gov lists Pfizer as sponsor of the MET233 trials. Whether the combination's phase 3 start has happened is not established here.

openFDA Drugs@FDA queries for MET233 and MET-233i each returned "No matches found" on 10 October 2026, while a control query for semaglutide returned records, and DailyMed drug name searches for the same names returned 0 labels. No FDA application or US label appears. Status outside the United States is not covered here.

Metsera 8-K exhibit, 29 September 2025: ultra-long acting monthly amylin analog candidate

Regulatory record

Metsera Form 8-K exhibit dated 29 September 2025. SEC EDGAR.

The exhibit writes the compound MET-233i and calls it an ultra-long acting monthly amylin analog candidate. It said topline 12-week data from the combination trials were expected at year-end 2025 or early 2026.

Participants / model
Company description, not a clinical population
Treatment
Subcutaneous injectable amylin analog
Follow-up
Statement dated 29 September 2025
Study design
Company filing exhibit
Funding
not stated in the source

A company statement. PubChem returned no record for MET-233i or MET233i on 10 October 2026, and the sources give no INN; those findings come from record searches, not from this exhibit.

Read the original source
Pfizer 10-Q, quarter ended 28 June 2026: Metsera acquisition and MET-233i combination milestones

Regulatory record

Pfizer Form 10-Q for the quarter ended 28 June 2026. SEC EDGAR.

Pfizer acquired Metsera on 13 November 2025 for $65.60 per share in cash plus a contingent value right of up to $20.65 per share. The CVR pays $4.60 after the phase 3 trial start of the MET-097i plus MET-233i combination, $6.40 after FDA approval of monthly MET-097i monotherapy, and $9.65 after FDA approval of the monthly MET-097i plus MET-233i combination. The filing calls MET-233i an amylin analog.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Quarter ended 28 June 2026
Study design
Company filing
Funding
not stated in the source

Whether the combination's phase 3 start has happened was not established. ClinicalTrials.gov lists Pfizer as sponsor of the MET233 trials.

Read the original source
FDA record search, 10 October 2026: no application or label

Regulatory record

U.S. Food and Drug Administration, openFDA Drugs@FDA queries and DailyMed drug name searches for MET233 and MET-233i, and for the Pfizer code PF-08653945, run on 10 October 2026.

openFDA Drugs@FDA queries for MET233 and MET-233i each returned "No matches found" (a control query for semaglutide returned records), and DailyMed drug name searches for the same names returned 0 labels. The same was true for the Pfizer code PF-08653945, whose link to MET-233i is not confirmed.

Participants / model
FDA databases, not a clinical population
Treatment
Name search
Follow-up
Queries run on 10 October 2026
Study design
Dated US approval-record search
Funding
not stated in the source

A search result shows what the databases returned on that date. It is US-scoped and does not cover approvals elsewhere.

Read the original source

What did the phase 1 results show?

The company reported in a 9 June 2025 filing that a single 2.4 mg dose gave 5.3% mean placebo-subtracted weight loss at day 8, and five weekly 1.2 mg doses gave 8.4% at day 36, in cohorts of 6 to 8 per dose. No peer-reviewed report was found.

In a Form 8-K dated 9 June 2025, Metsera reported a phase 1 single ascending dose study. 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg, the company reported a mean placebo-subtracted weight loss of 5.3% at day 8, with a placebo change of 0.9%. The filing does not state the sign of the placebo change or the population, and the registry lists otherwise healthy adults with obesity or overweight.

The same filing reported a multiple ascending dose study in which 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and the filing says weight loss was dose dependent across most cohorts. The 8.4% is a five-week mean in small cohorts with no confidence interval in the filing.

Both sets of figures are a company statement in an SEC filing. PubMed queries on 10 October 2026 for MET233, MET-233, MET-233i and MET233i returned 6, 4, 1 and 1 records, and no peer-reviewed report of MET-233i trial data was found. A 2026 narrative review (PMID 42452898) tabulates MET-233i as 1.2 mg weekly with about 8.4% weight loss at 5 weeks, but it cites the June 2025 Metsera press release and adds no independent data.

A larger phase 1 is registered with no posted results. NCT07022977 (Pfizer) is a randomized, quadruple-masked, single and multiple ascending dose study in otherwise healthy adults with obesity or overweight, 144 participants (actual), completed on 21 April 2026, with treatment-emergent adverse events as the primary outcome. The registry's 144 covers parts A to D, while the 8-K's 80 is the single dose (40) plus multiple dose (40) participants, so the counts differ and the later parts' numbers are not given. Results from the later parts were not found. A registration is not an outcome.

Company statement, 9 June 2025: phase 1, 40 and 40 participants, not peer reviewed

Clinical trial

Metsera Form 8-K dated 9 June 2025. SEC EDGAR.

Single ascending dose: 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg the mean placebo-subtracted weight loss was 5.3% at day 8, with a placebo change of 0.9% (sign not stated). Nausea occurred in 5 of 6 (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%), with moderate nausea in 2 of 6 and moderate vomiting in 1 of 6 at 1.2 mg and no severe events. No placebo participant had a gastrointestinal event. Multiple ascending dose: 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and weight loss was dose dependent across most cohorts. Gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued and none was attributed to adverse events. The filing reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration.

Participants / model
Participants in single and multiple ascending dose phase 1 studies; the 8-K does not give the population, and the registry lists otherwise healthy adults with obesity or overweight
Treatment
Single subcutaneous dose (single ascending dose) and five weekly subcutaneous doses (multiple ascending dose)
Follow-up
Body weight at day 8 (single dose) and day 36 (five weekly doses)
Study design
Company statement in an SEC filing of phase 1 results; not peer reviewed; no confidence intervals
Funding
not stated in the source

Company-reported results in small cohorts of 6 to 8 per dose. The 8.4% is a five-week mean with no confidence interval in the filing. The filing's half-life definition is not a standard terminal half-life definition. No peer-reviewed report was found.

Read the original source
PubMed search, 10 October 2026: no peer-reviewed report of MET-233i trial data

PubMed search record

PubMed searches run on 10 October 2026 for MET233, MET-233, MET-233i and MET233i, returning 6, 4, 1 and 1 records.

The four queries returned 6, 4, 1 and 1 records. Two were 2026 narrative reviews. The review in PMID 42452898 tabulates MET-233i as 1.2 mg weekly with about 8.4% weight loss at 5 weeks and cites the June 2025 Metsera press release, so it adds no independent data. The abstract of PMID 41747885 lists Met-233 among analogs that have shown efficacy as monotherapy in clinical trials without giving data, and its full text was not read. The rest were unrelated papers on a receptor residue and a bacterial protein. No peer-reviewed report of MET-233i trial data was found.

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

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

Read the original source
Registry: larger phase 1, 144 participants, completed, no posted results

Trial registry record

ClinicalTrials.gov. NCT07022977 (sponsor Pfizer).

NCT07022977 is a randomized, quadruple-masked, single and multiple ascending dose study in otherwise healthy adults with obesity or overweight, 144 participants (actual), completed on 21 April 2026, with treatment-emergent adverse events as the primary outcome. Its parts include a 12-week weekly dosing arm followed by a single higher, potential monthly dose, and a part with twelve weekly doses followed by three monthly doses. The registry has no posted results. A registration is not an outcome.

Participants / model
Otherwise healthy adults with obesity or overweight
Treatment
Subcutaneous weekly and monthly dosing
Follow-up
Completed 21 April 2026
Study design
Official trial registry
Funding
not stated in the source

The registry's 144 covers parts A to D, while the 8-K's 80 is the single dose (40) plus multiple dose (40) participants, so the counts differ and the later parts' numbers are not given. Results from the later parts were not found.

Read the original source

Is MET-233i being developed together with MET-097i?

Yes, as a plan. Pfizer's 10-Q ties milestone payments to a MET-097i plus MET-233i combination, and a phase 1/2 study of the pair (NCT06924320) is registered with no posted results. The 12-week combination readout Metsera expected for year-end 2025 or early 2026 was not found.

Pfizer's 10-Q describes a contingent value right that pays after the phase 3 trial start of the MET-097i plus MET-233i combination and after FDA approval of the monthly combination. That confirms the combination as a development plan with milestones attached.

NCT06924320 (Pfizer) is a phase 1/2 randomized, quadruple-masked study of MET233 given with MET097, in adults 18 to 75 with obesity or overweight with or without diabetes, estimated 381 participants, started on 6 March 2025, with treatment-emergent adverse events as the primary outcome. It was still listed as recruiting at the 1 June 2026 update, with no posted results.

Metsera's 8-K exhibit of 29 September 2025 said topline 12-week data from the combination trials were expected at year-end 2025 or early 2026. No such readout was found in the records reviewed. A registration is not an outcome.

Pfizer 10-Q, quarter ended 28 June 2026: Metsera acquisition and MET-233i combination milestones

Regulatory record

Pfizer Form 10-Q for the quarter ended 28 June 2026. SEC EDGAR.

Pfizer acquired Metsera on 13 November 2025 for $65.60 per share in cash plus a contingent value right of up to $20.65 per share. The CVR pays $4.60 after the phase 3 trial start of the MET-097i plus MET-233i combination, $6.40 after FDA approval of monthly MET-097i monotherapy, and $9.65 after FDA approval of the monthly MET-097i plus MET-233i combination. The filing calls MET-233i an amylin analog.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Quarter ended 28 June 2026
Study design
Company filing
Funding
not stated in the source

Whether the combination's phase 3 start has happened was not established. ClinicalTrials.gov lists Pfizer as sponsor of the MET233 trials.

Read the original source
Registry: MET233 with MET097, 381 planned, recruiting, no posted results

Trial registry record

ClinicalTrials.gov. NCT06924320 (sponsor Pfizer).

NCT06924320 is a phase 1/2 randomized, quadruple-masked study of MET233 given with MET097, in adults 18 to 75 with obesity or overweight with or without diabetes, estimated 381 participants, started on 6 March 2025, with treatment-emergent adverse events as the primary outcome. It was still listed as recruiting at the 1 June 2026 update, with no posted results.

Participants / model
Adults with obesity or overweight, with or without type 2 diabetes
Treatment
Subcutaneous, MET233 with MET097
Follow-up
Started 6 March 2025; still recruiting at the 1 June 2026 update
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The 12-week combination readout that Metsera's 29 September 2025 exhibit expected at year-end 2025 or early 2026 was not found.

Read the original source
Metsera 8-K exhibit, 29 September 2025: ultra-long acting monthly amylin analog candidate

Regulatory record

Metsera Form 8-K exhibit dated 29 September 2025. SEC EDGAR.

The exhibit writes the compound MET-233i and calls it an ultra-long acting monthly amylin analog candidate. It said topline 12-week data from the combination trials were expected at year-end 2025 or early 2026.

Participants / model
Company description, not a clinical population
Treatment
Subcutaneous injectable amylin analog
Follow-up
Statement dated 29 September 2025
Study design
Company filing exhibit
Funding
not stated in the source

A company statement. PubChem returned no record for MET-233i or MET233i on 10 October 2026, and the sources give no INN; those findings come from record searches, not from this exhibit.

Read the original source

Is Pfizer's code PF-08653945 the same compound?

Not confirmed. A Pfizer phase 2b study, SOLIS-1, is registered under PF-08653945, and Pfizer describes PF'3945 as an ultra-long-acting amylin analog, but no primary document reviewed states that PF-08653945 is MET-233i. The link was suggested only by third-party tracker listings.

SOLIS-1 (NCT07575932, Pfizer) is a randomized, double-blind, placebo-controlled umbrella study of PF-08653945 and PF-08653944 alone or together in adults with overweight or obesity, 940 participants (actual), started on 11 May 2026, active not recruiting, with percent change in body weight to week 48 as the primary outcome and no results. NCT07725809 is a phase 1 injection-site bioavailability study of PF-08653945 (estimated 57, Belgium). No registered phase 3 trial naming MET233, MET-233i or PF-08653945 was found.

Pfizer's 6 June 2026 release says berobenatide (PF'3944) was previously called MET-097i, and that SOLIS-1 studies weekly and monthly maintenance dosing of "an ultra-long-acting amylin analog (PF'3945)" alone and with berobenatide. Pfizer's filings name MET-233i as the amylin analog acquired with Metsera, but no primary document reviewed states that PF-08653945 is MET-233i. The connection was suggested only by third-party tracker listings in search results, so it is a reported link, not a confirmed one. SOLIS-1 is therefore not counted as MET-233i data on this page.

Registry: SOLIS-1 phase 2b under a Pfizer code whose link to MET-233i is not confirmed

Trial registry record

ClinicalTrials.gov. NCT07575932 (sponsor Pfizer), with related record NCT07725809.

SOLIS-1 (NCT07575932, Pfizer) is a randomized, double-blind, placebo-controlled umbrella study of PF-08653945 and PF-08653944 alone or together in adults with overweight or obesity, 940 participants (actual), started on 11 May 2026, active not recruiting, with percent change in body weight to week 48 as the primary outcome and no results. NCT07725809 is a phase 1 injection-site bioavailability study of PF-08653945 (estimated 57, Belgium). No registered phase 3 trial naming MET233, MET-233i or PF-08653945 was found.

Participants / model
Adults with overweight or obesity (planned)
Treatment
Subcutaneous
Follow-up
Primary outcome at week 48 (planned)
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The link between PF-08653945 and MET-233i is not confirmed, so this study is not counted as MET-233i data.

Read the original source
Pfizer release, 6 June 2026: berobenatide, previously MET-097i, and an amylin analog (PF'3945)

Regulatory record

Pfizer news release dated 6 June 2026 on berobenatide results and the SOLIS-1 study design.

The release says berobenatide (PF'3944) was previously called MET-097i, and that SOLIS-1 studies weekly and monthly maintenance dosing of "an ultra-long-acting amylin analog (PF'3945)" alone and with berobenatide. It also reports berobenatide results (VESPER-1: almost 16% non-placebo-adjusted weight loss at 32 weeks on 2.4 mg weekly, a company statement). Registered berobenatide phase 3 trials include weekly (NCT07311850) and monthly (NCT07823608) regimens.

Participants / model
Not a clinical population for the identity statements; berobenatide trial participants for the VESPER-1 figure
Treatment
Not applicable
Follow-up
Statement dated 6 June 2026
Study design
Company news release
Funding
not stated in the source

No primary document reviewed states that PF-08653945 is MET-233i. The berobenatide results are the partner compound's data, not MET-233i data.

Read the original source

Is MET-233 a Pfizer amylin analog being combined with the monthly GLP-1 MET-097?

Largely, as a development plan. Pfizer owns MET-233i through the Metsera acquisition, and a MET-097i plus MET-233i combination is the stated plan, but that plan is backed by phase 1 data only. Monthly dosing is a goal for the partner compound rather than its only registered regimen.

The claim describes a Pfizer amylin analog, acquired through Metsera, being combined with MET-097, the monthly GLP-1.

Pfizer's 10-Q confirms the acquisition and calls MET-233i an amylin analog, and the combination is the stated plan with milestones attached. The efficacy and safety data behind that plan are two company-reported phase 1 parts in small cohorts, with no peer-reviewed report.

Pfizer's 6 June 2026 release says berobenatide was previously called MET-097i. It reports berobenatide results (VESPER-1: almost 16% non-placebo-adjusted weight loss at 32 weeks on 2.4 mg weekly, a company statement), and those are the partner compound's data, not MET-233i's. Registered berobenatide phase 3 trials include weekly (NCT07311850) and monthly (NCT07823608) regimens, so monthly dosing is a goal for the partner rather than its only registered regimen.

Pfizer 10-Q, quarter ended 28 June 2026: Metsera acquisition and MET-233i combination milestones

Regulatory record

Pfizer Form 10-Q for the quarter ended 28 June 2026. SEC EDGAR.

Pfizer acquired Metsera on 13 November 2025 for $65.60 per share in cash plus a contingent value right of up to $20.65 per share. The CVR pays $4.60 after the phase 3 trial start of the MET-097i plus MET-233i combination, $6.40 after FDA approval of monthly MET-097i monotherapy, and $9.65 after FDA approval of the monthly MET-097i plus MET-233i combination. The filing calls MET-233i an amylin analog.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Quarter ended 28 June 2026
Study design
Company filing
Funding
not stated in the source

Whether the combination's phase 3 start has happened was not established. ClinicalTrials.gov lists Pfizer as sponsor of the MET233 trials.

Read the original source
Pfizer release, 6 June 2026: berobenatide, previously MET-097i, and an amylin analog (PF'3945)

Regulatory record

Pfizer news release dated 6 June 2026 on berobenatide results and the SOLIS-1 study design.

The release says berobenatide (PF'3944) was previously called MET-097i, and that SOLIS-1 studies weekly and monthly maintenance dosing of "an ultra-long-acting amylin analog (PF'3945)" alone and with berobenatide. It also reports berobenatide results (VESPER-1: almost 16% non-placebo-adjusted weight loss at 32 weeks on 2.4 mg weekly, a company statement). Registered berobenatide phase 3 trials include weekly (NCT07311850) and monthly (NCT07823608) regimens.

Participants / model
Not a clinical population for the identity statements; berobenatide trial participants for the VESPER-1 figure
Treatment
Not applicable
Follow-up
Statement dated 6 June 2026
Study design
Company news release
Funding
not stated in the source

No primary document reviewed states that PF-08653945 is MET-233i. The berobenatide results are the partner compound's data, not MET-233i data.

Read the original source
Company statement, 9 June 2025: phase 1, 40 and 40 participants, not peer reviewed

Clinical trial

Metsera Form 8-K dated 9 June 2025. SEC EDGAR.

Single ascending dose: 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg the mean placebo-subtracted weight loss was 5.3% at day 8, with a placebo change of 0.9% (sign not stated). Nausea occurred in 5 of 6 (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%), with moderate nausea in 2 of 6 and moderate vomiting in 1 of 6 at 1.2 mg and no severe events. No placebo participant had a gastrointestinal event. Multiple ascending dose: 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and weight loss was dose dependent across most cohorts. Gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued and none was attributed to adverse events. The filing reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration.

Participants / model
Participants in single and multiple ascending dose phase 1 studies; the 8-K does not give the population, and the registry lists otherwise healthy adults with obesity or overweight
Treatment
Single subcutaneous dose (single ascending dose) and five weekly subcutaneous doses (multiple ascending dose)
Follow-up
Body weight at day 8 (single dose) and day 36 (five weekly doses)
Study design
Company statement in an SEC filing of phase 1 results; not peer reviewed; no confidence intervals
Funding
not stated in the source

Company-reported results in small cohorts of 6 to 8 per dose. The 8.4% is a five-week mean with no confidence interval in the filing. The filing's half-life definition is not a standard terminal half-life definition. No peer-reviewed report was found.

Read the original source

How does MET-233 work, and how long does it last in the body?

MET-233i is described as an ultra-long acting amylin analog, and no structure is public in the records reviewed. A company filing reported a half-life of about 19 days, defined as the time to 50% of maximum concentration, which is not a standard definition.

Metsera describes MET-233i as an ultra-long acting monthly amylin analog candidate, and Pfizer's filing calls it an amylin analog. No structure, formula or molecular weight is public in the records reviewed, so nothing more about its chemistry or receptor activity is described here. The amylin mechanism has support from class data, such as the published phase 2 trial of petrelintide on its own page.

The Metsera filing of 9 June 2025 reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration, which is not a standard terminal half-life definition. It is a company-reported figure and is not comparable with a standard terminal half-life.

Metsera 8-K exhibit, 29 September 2025: ultra-long acting monthly amylin analog candidate

Regulatory record

Metsera Form 8-K exhibit dated 29 September 2025. SEC EDGAR.

The exhibit writes the compound MET-233i and calls it an ultra-long acting monthly amylin analog candidate. It said topline 12-week data from the combination trials were expected at year-end 2025 or early 2026.

Participants / model
Company description, not a clinical population
Treatment
Subcutaneous injectable amylin analog
Follow-up
Statement dated 29 September 2025
Study design
Company filing exhibit
Funding
not stated in the source

A company statement. PubChem returned no record for MET-233i or MET233i on 10 October 2026, and the sources give no INN; those findings come from record searches, not from this exhibit.

Read the original source
Pfizer 10-Q, quarter ended 28 June 2026: Metsera acquisition and MET-233i combination milestones

Regulatory record

Pfizer Form 10-Q for the quarter ended 28 June 2026. SEC EDGAR.

Pfizer acquired Metsera on 13 November 2025 for $65.60 per share in cash plus a contingent value right of up to $20.65 per share. The CVR pays $4.60 after the phase 3 trial start of the MET-097i plus MET-233i combination, $6.40 after FDA approval of monthly MET-097i monotherapy, and $9.65 after FDA approval of the monthly MET-097i plus MET-233i combination. The filing calls MET-233i an amylin analog.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Quarter ended 28 June 2026
Study design
Company filing
Funding
not stated in the source

Whether the combination's phase 3 start has happened was not established. ClinicalTrials.gov lists Pfizer as sponsor of the MET233 trials.

Read the original source
Company statement, 9 June 2025: phase 1, 40 and 40 participants, not peer reviewed

Clinical trial

Metsera Form 8-K dated 9 June 2025. SEC EDGAR.

Single ascending dose: 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg the mean placebo-subtracted weight loss was 5.3% at day 8, with a placebo change of 0.9% (sign not stated). Nausea occurred in 5 of 6 (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%), with moderate nausea in 2 of 6 and moderate vomiting in 1 of 6 at 1.2 mg and no severe events. No placebo participant had a gastrointestinal event. Multiple ascending dose: 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and weight loss was dose dependent across most cohorts. Gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued and none was attributed to adverse events. The filing reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration.

Participants / model
Participants in single and multiple ascending dose phase 1 studies; the 8-K does not give the population, and the registry lists otherwise healthy adults with obesity or overweight
Treatment
Single subcutaneous dose (single ascending dose) and five weekly subcutaneous doses (multiple ascending dose)
Follow-up
Body weight at day 8 (single dose) and day 36 (five weekly doses)
Study design
Company statement in an SEC filing of phase 1 results; not peer reviewed; no confidence intervals
Funding
not stated in the source

Company-reported results in small cohorts of 6 to 8 per dose. The 8.4% is a five-week mean with no confidence interval in the filing. The filing's half-life definition is not a standard terminal half-life definition. No peer-reviewed report was found.

Read the original source

What risks did the phase 1 results report?

In the company-reported results, gastrointestinal adverse events were dose dependent and frequent: nausea in 6 of 6 at 2.4 mg after one dose and in 8 of 8 at 1.2 mg after five weekly doses. None was severe, and 3 of 40 participants discontinued in the multiple dose study, none for adverse events.

In the single ascending dose study, nausea occurred in 5 of 6 participants (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%). Nausea was moderate in 2 of 6 and vomiting moderate in 1 of 6 at 1.2 mg, and there were no severe events. No placebo participant had a gastrointestinal event.

In the multiple ascending dose study, gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued, and none was attributed to adverse events.

These are company statements from cohorts of 6 to 8 per dose. No peer-reviewed safety report exists, and the larger registered phase 1 and phase 1/2 studies have no posted results.

Company statement, 9 June 2025: phase 1, 40 and 40 participants, not peer reviewed

Clinical trial

Metsera Form 8-K dated 9 June 2025. SEC EDGAR.

Single ascending dose: 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg the mean placebo-subtracted weight loss was 5.3% at day 8, with a placebo change of 0.9% (sign not stated). Nausea occurred in 5 of 6 (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%), with moderate nausea in 2 of 6 and moderate vomiting in 1 of 6 at 1.2 mg and no severe events. No placebo participant had a gastrointestinal event. Multiple ascending dose: 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and weight loss was dose dependent across most cohorts. Gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued and none was attributed to adverse events. The filing reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration.

Participants / model
Participants in single and multiple ascending dose phase 1 studies; the 8-K does not give the population, and the registry lists otherwise healthy adults with obesity or overweight
Treatment
Single subcutaneous dose (single ascending dose) and five weekly subcutaneous doses (multiple ascending dose)
Follow-up
Body weight at day 8 (single dose) and day 36 (five weekly doses)
Study design
Company statement in an SEC filing of phase 1 results; not peer reviewed; no confidence intervals
Funding
not stated in the source

Company-reported results in small cohorts of 6 to 8 per dose. The 8.4% is a five-week mean with no confidence interval in the filing. The filing's half-life definition is not a standard terminal half-life definition. No peer-reviewed report was found.

Read the original source
Registry: larger phase 1, 144 participants, completed, no posted results

Trial registry record

ClinicalTrials.gov. NCT07022977 (sponsor Pfizer).

NCT07022977 is a randomized, quadruple-masked, single and multiple ascending dose study in otherwise healthy adults with obesity or overweight, 144 participants (actual), completed on 21 April 2026, with treatment-emergent adverse events as the primary outcome. Its parts include a 12-week weekly dosing arm followed by a single higher, potential monthly dose, and a part with twelve weekly doses followed by three monthly doses. The registry has no posted results. A registration is not an outcome.

Participants / model
Otherwise healthy adults with obesity or overweight
Treatment
Subcutaneous weekly and monthly dosing
Follow-up
Completed 21 April 2026
Study design
Official trial registry
Funding
not stated in the source

The registry's 144 covers parts A to D, while the 8-K's 80 is the single dose (40) plus multiple dose (40) participants, so the counts differ and the later parts' numbers are not given. Results from the later parts were not found.

Read the original source
Registry: MET233 with MET097, 381 planned, recruiting, no posted results

Trial registry record

ClinicalTrials.gov. NCT06924320 (sponsor Pfizer).

NCT06924320 is a phase 1/2 randomized, quadruple-masked study of MET233 given with MET097, in adults 18 to 75 with obesity or overweight with or without diabetes, estimated 381 participants, started on 6 March 2025, with treatment-emergent adverse events as the primary outcome. It was still listed as recruiting at the 1 June 2026 update, with no posted results.

Participants / model
Adults with obesity or overweight, with or without type 2 diabetes
Treatment
Subcutaneous, MET233 with MET097
Follow-up
Started 6 March 2025; still recruiting at the 1 June 2026 update
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The 12-week combination readout that Metsera's 29 September 2025 exhibit expected at year-end 2025 or early 2026 was not found.

Read the original source

Why does MET-233 sit in C tier?

The only efficacy data are two company-reported phase 1 parts of 40 participants each, with cohorts of 6 to 8 per dose and no peer-reviewed report. Nausea was frequent at higher doses, the promised 12-week readouts were not found, and the larger studies have no posted results.

The C reflects efficacy data limited to two company-reported phase 1 parts in an SEC filing (a single dose in one part and five weekly doses in the other), with no confidence intervals and no peer-reviewed report. The amylin mechanism has support from class data, such as the published phase 2 trial of petrelintide on its own page.

Against that, nausea occurred in all 8 participants at 1.2 mg after five weekly doses, the 12-week monotherapy and combination readouts were promised and not found, and the later phase 1 and phase 1/2 studies have no posted results. A phase 2b study exists on paper under a code whose link to MET-233i is not confirmed. The combination with MET-097i is a stated plan backed by phase 1 data only.

Company statement, 9 June 2025: phase 1, 40 and 40 participants, not peer reviewed

Clinical trial

Metsera Form 8-K dated 9 June 2025. SEC EDGAR.

Single ascending dose: 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg the mean placebo-subtracted weight loss was 5.3% at day 8, with a placebo change of 0.9% (sign not stated). Nausea occurred in 5 of 6 (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%), with moderate nausea in 2 of 6 and moderate vomiting in 1 of 6 at 1.2 mg and no severe events. No placebo participant had a gastrointestinal event. Multiple ascending dose: 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and weight loss was dose dependent across most cohorts. Gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued and none was attributed to adverse events. The filing reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration.

Participants / model
Participants in single and multiple ascending dose phase 1 studies; the 8-K does not give the population, and the registry lists otherwise healthy adults with obesity or overweight
Treatment
Single subcutaneous dose (single ascending dose) and five weekly subcutaneous doses (multiple ascending dose)
Follow-up
Body weight at day 8 (single dose) and day 36 (five weekly doses)
Study design
Company statement in an SEC filing of phase 1 results; not peer reviewed; no confidence intervals
Funding
not stated in the source

Company-reported results in small cohorts of 6 to 8 per dose. The 8.4% is a five-week mean with no confidence interval in the filing. The filing's half-life definition is not a standard terminal half-life definition. No peer-reviewed report was found.

Read the original source
PubMed search, 10 October 2026: no peer-reviewed report of MET-233i trial data

PubMed search record

PubMed searches run on 10 October 2026 for MET233, MET-233, MET-233i and MET233i, returning 6, 4, 1 and 1 records.

The four queries returned 6, 4, 1 and 1 records. Two were 2026 narrative reviews. The review in PMID 42452898 tabulates MET-233i as 1.2 mg weekly with about 8.4% weight loss at 5 weeks and cites the June 2025 Metsera press release, so it adds no independent data. The abstract of PMID 41747885 lists Met-233 among analogs that have shown efficacy as monotherapy in clinical trials without giving data, and its full text was not read. The rest were unrelated papers on a receptor residue and a bacterial protein. No peer-reviewed report of MET-233i trial data was found.

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

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

Read the original source
Registry: larger phase 1, 144 participants, completed, no posted results

Trial registry record

ClinicalTrials.gov. NCT07022977 (sponsor Pfizer).

NCT07022977 is a randomized, quadruple-masked, single and multiple ascending dose study in otherwise healthy adults with obesity or overweight, 144 participants (actual), completed on 21 April 2026, with treatment-emergent adverse events as the primary outcome. Its parts include a 12-week weekly dosing arm followed by a single higher, potential monthly dose, and a part with twelve weekly doses followed by three monthly doses. The registry has no posted results. A registration is not an outcome.

Participants / model
Otherwise healthy adults with obesity or overweight
Treatment
Subcutaneous weekly and monthly dosing
Follow-up
Completed 21 April 2026
Study design
Official trial registry
Funding
not stated in the source

The registry's 144 covers parts A to D, while the 8-K's 80 is the single dose (40) plus multiple dose (40) participants, so the counts differ and the later parts' numbers are not given. Results from the later parts were not found.

Read the original source
Registry: MET233 with MET097, 381 planned, recruiting, no posted results

Trial registry record

ClinicalTrials.gov. NCT06924320 (sponsor Pfizer).

NCT06924320 is a phase 1/2 randomized, quadruple-masked study of MET233 given with MET097, in adults 18 to 75 with obesity or overweight with or without diabetes, estimated 381 participants, started on 6 March 2025, with treatment-emergent adverse events as the primary outcome. It was still listed as recruiting at the 1 June 2026 update, with no posted results.

Participants / model
Adults with obesity or overweight, with or without type 2 diabetes
Treatment
Subcutaneous, MET233 with MET097
Follow-up
Started 6 March 2025; still recruiting at the 1 June 2026 update
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The 12-week combination readout that Metsera's 29 September 2025 exhibit expected at year-end 2025 or early 2026 was not found.

Read the original source
Registry: SOLIS-1 phase 2b under a Pfizer code whose link to MET-233i is not confirmed

Trial registry record

ClinicalTrials.gov. NCT07575932 (sponsor Pfizer), with related record NCT07725809.

SOLIS-1 (NCT07575932, Pfizer) is a randomized, double-blind, placebo-controlled umbrella study of PF-08653945 and PF-08653944 alone or together in adults with overweight or obesity, 940 participants (actual), started on 11 May 2026, active not recruiting, with percent change in body weight to week 48 as the primary outcome and no results. NCT07725809 is a phase 1 injection-site bioavailability study of PF-08653945 (estimated 57, Belgium). No registered phase 3 trial naming MET233, MET-233i or PF-08653945 was found.

Participants / model
Adults with overweight or obesity (planned)
Treatment
Subcutaneous
Follow-up
Primary outcome at week 48 (planned)
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The link between PF-08653945 and MET-233i is not confirmed, so this study is not counted as MET-233i data.

Read the original source

Studies and sources

Metsera 8-K exhibit, 29 September 2025: ultra-long acting monthly amylin analog candidate

Regulatory record

Metsera Form 8-K exhibit dated 29 September 2025. SEC EDGAR.

The exhibit writes the compound MET-233i and calls it an ultra-long acting monthly amylin analog candidate. It said topline 12-week data from the combination trials were expected at year-end 2025 or early 2026.

Participants / model
Company description, not a clinical population
Treatment
Subcutaneous injectable amylin analog
Follow-up
Statement dated 29 September 2025
Study design
Company filing exhibit
Funding
not stated in the source

A company statement. PubChem returned no record for MET-233i or MET233i on 10 October 2026, and the sources give no INN; those findings come from record searches, not from this exhibit.

Read the original source
Pfizer 10-Q, quarter ended 28 June 2026: Metsera acquisition and MET-233i combination milestones

Regulatory record

Pfizer Form 10-Q for the quarter ended 28 June 2026. SEC EDGAR.

Pfizer acquired Metsera on 13 November 2025 for $65.60 per share in cash plus a contingent value right of up to $20.65 per share. The CVR pays $4.60 after the phase 3 trial start of the MET-097i plus MET-233i combination, $6.40 after FDA approval of monthly MET-097i monotherapy, and $9.65 after FDA approval of the monthly MET-097i plus MET-233i combination. The filing calls MET-233i an amylin analog.

Participants / model
Not a clinical population
Treatment
Not applicable
Follow-up
Quarter ended 28 June 2026
Study design
Company filing
Funding
not stated in the source

Whether the combination's phase 3 start has happened was not established. ClinicalTrials.gov lists Pfizer as sponsor of the MET233 trials.

Read the original source
Company statement, 9 June 2025: phase 1, 40 and 40 participants, not peer reviewed

Clinical trial

Metsera Form 8-K dated 9 June 2025. SEC EDGAR.

Single ascending dose: 40 participants in five cohorts received one dose of placebo (10 participants) or 0.15, 0.30, 0.60, 1.2 or 2.4 mg MET-233i (6 per dose). At 2.4 mg the mean placebo-subtracted weight loss was 5.3% at day 8, with a placebo change of 0.9% (sign not stated). Nausea occurred in 5 of 6 (83.3%) at 1.2 mg and 6 of 6 (100%) at 2.4 mg, and vomiting in 4 of 6 (66.7%) and 5 of 6 (83.3%), with moderate nausea in 2 of 6 and moderate vomiting in 1 of 6 at 1.2 mg and no severe events. No placebo participant had a gastrointestinal event. Multiple ascending dose: 40 participants in four cohorts received five weekly doses of placebo (8 participants) or 0.15, 0.30, 0.60 or 1.2 mg MET-233i (8 per dose). At 1.2 mg the mean placebo-subtracted weight loss was 8.4% at day 36, with a placebo change of 0.6% (sign not stated), and weight loss was dose dependent across most cohorts. Gastrointestinal events were all mild and mostly in the first week: nausea in 6 of 8 (75%) at 0.6 mg and 8 of 8 (100%) at 1.2 mg versus 1 of 8 on placebo, and vomiting in 3 of 8 (37.5%) at each of those doses versus none on placebo. 3 of 40 participants (7.5%) discontinued and none was attributed to adverse events. The filing reports a half-life of about 19 days, defined there as the time from administration to 50% of maximum observed concentration.

Participants / model
Participants in single and multiple ascending dose phase 1 studies; the 8-K does not give the population, and the registry lists otherwise healthy adults with obesity or overweight
Treatment
Single subcutaneous dose (single ascending dose) and five weekly subcutaneous doses (multiple ascending dose)
Follow-up
Body weight at day 8 (single dose) and day 36 (five weekly doses)
Study design
Company statement in an SEC filing of phase 1 results; not peer reviewed; no confidence intervals
Funding
not stated in the source

Company-reported results in small cohorts of 6 to 8 per dose. The 8.4% is a five-week mean with no confidence interval in the filing. The filing's half-life definition is not a standard terminal half-life definition. No peer-reviewed report was found.

Read the original source
Registry: larger phase 1, 144 participants, completed, no posted results

Trial registry record

ClinicalTrials.gov. NCT07022977 (sponsor Pfizer).

NCT07022977 is a randomized, quadruple-masked, single and multiple ascending dose study in otherwise healthy adults with obesity or overweight, 144 participants (actual), completed on 21 April 2026, with treatment-emergent adverse events as the primary outcome. Its parts include a 12-week weekly dosing arm followed by a single higher, potential monthly dose, and a part with twelve weekly doses followed by three monthly doses. The registry has no posted results. A registration is not an outcome.

Participants / model
Otherwise healthy adults with obesity or overweight
Treatment
Subcutaneous weekly and monthly dosing
Follow-up
Completed 21 April 2026
Study design
Official trial registry
Funding
not stated in the source

The registry's 144 covers parts A to D, while the 8-K's 80 is the single dose (40) plus multiple dose (40) participants, so the counts differ and the later parts' numbers are not given. Results from the later parts were not found.

Read the original source
Registry: MET233 with MET097, 381 planned, recruiting, no posted results

Trial registry record

ClinicalTrials.gov. NCT06924320 (sponsor Pfizer).

NCT06924320 is a phase 1/2 randomized, quadruple-masked study of MET233 given with MET097, in adults 18 to 75 with obesity or overweight with or without diabetes, estimated 381 participants, started on 6 March 2025, with treatment-emergent adverse events as the primary outcome. It was still listed as recruiting at the 1 June 2026 update, with no posted results.

Participants / model
Adults with obesity or overweight, with or without type 2 diabetes
Treatment
Subcutaneous, MET233 with MET097
Follow-up
Started 6 March 2025; still recruiting at the 1 June 2026 update
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The 12-week combination readout that Metsera's 29 September 2025 exhibit expected at year-end 2025 or early 2026 was not found.

Read the original source
Registry: SOLIS-1 phase 2b under a Pfizer code whose link to MET-233i is not confirmed

Trial registry record

ClinicalTrials.gov. NCT07575932 (sponsor Pfizer), with related record NCT07725809.

SOLIS-1 (NCT07575932, Pfizer) is a randomized, double-blind, placebo-controlled umbrella study of PF-08653945 and PF-08653944 alone or together in adults with overweight or obesity, 940 participants (actual), started on 11 May 2026, active not recruiting, with percent change in body weight to week 48 as the primary outcome and no results. NCT07725809 is a phase 1 injection-site bioavailability study of PF-08653945 (estimated 57, Belgium). No registered phase 3 trial naming MET233, MET-233i or PF-08653945 was found.

Participants / model
Adults with overweight or obesity (planned)
Treatment
Subcutaneous
Follow-up
Primary outcome at week 48 (planned)
Study design
Official trial registry
Funding
not stated in the source

A registration, not an outcome. The link between PF-08653945 and MET-233i is not confirmed, so this study is not counted as MET-233i data.

Read the original source
Pfizer release, 6 June 2026: berobenatide, previously MET-097i, and an amylin analog (PF'3945)

Regulatory record

Pfizer news release dated 6 June 2026 on berobenatide results and the SOLIS-1 study design.

The release says berobenatide (PF'3944) was previously called MET-097i, and that SOLIS-1 studies weekly and monthly maintenance dosing of "an ultra-long-acting amylin analog (PF'3945)" alone and with berobenatide. It also reports berobenatide results (VESPER-1: almost 16% non-placebo-adjusted weight loss at 32 weeks on 2.4 mg weekly, a company statement). Registered berobenatide phase 3 trials include weekly (NCT07311850) and monthly (NCT07823608) regimens.

Participants / model
Not a clinical population for the identity statements; berobenatide trial participants for the VESPER-1 figure
Treatment
Not applicable
Follow-up
Statement dated 6 June 2026
Study design
Company news release
Funding
not stated in the source

No primary document reviewed states that PF-08653945 is MET-233i. The berobenatide results are the partner compound's data, not MET-233i data.

Read the original source
PubMed search, 10 October 2026: no peer-reviewed report of MET-233i trial data

PubMed search record

PubMed searches run on 10 October 2026 for MET233, MET-233, MET-233i and MET233i, returning 6, 4, 1 and 1 records.

The four queries returned 6, 4, 1 and 1 records. Two were 2026 narrative reviews. The review in PMID 42452898 tabulates MET-233i as 1.2 mg weekly with about 8.4% weight loss at 5 weeks and cites the June 2025 Metsera press release, so it adds no independent data. The abstract of PMID 41747885 lists Met-233 among analogs that have shown efficacy as monotherapy in clinical trials without giving data, and its full text was not read. The rest were unrelated papers on a receptor residue and a bacterial protein. No peer-reviewed report of MET-233i trial data was found.

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

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

Read the original source
FDA record search, 10 October 2026: no application or label

Regulatory record

U.S. Food and Drug Administration, openFDA Drugs@FDA queries and DailyMed drug name searches for MET233 and MET-233i, and for the Pfizer code PF-08653945, run on 10 October 2026.

openFDA Drugs@FDA queries for MET233 and MET-233i each returned "No matches found" (a control query for semaglutide returned records), and DailyMed drug name searches for the same names returned 0 labels. The same was true for the Pfizer code PF-08653945, whose link to MET-233i is not confirmed.

Participants / model
FDA databases, not a clinical population
Treatment
Name search
Follow-up
Queries run on 10 October 2026
Study design
Dated US approval-record search
Funding
not stated in the source

A search result shows what the databases returned on that date. It is US-scoped and does not cover approvals elsewhere.

Read the original source

Why is MET-233 in C tier?

C fits a compound whose only efficacy data are two company-reported phase 1 parts of 40 participants each, with cohorts of 6 to 8 per dose, no confidence intervals and no peer-reviewed report. The amylin mechanism has class support, but nausea was frequent at the higher doses, the promised 12-week readouts were not found, and the larger studies have no posted results.