Efficacy and Safety of Tirzepatide in Japanese Participants With Obesity: A Subpopulation Analysis of the SURMOUNT-1 Trial.

Ishigaki Y, Yamada M, Shingaki T, Oura T, Shimomura I

Obesity (Silver Spring, Md.)30 Jan 2026

PMID41612966PMCIDPMC12933229DOI10.1002/oby.70131PepBankPUB-41612966

Summary

ObjectiveThis prespecified subpopulation analysis aimed to assess the efficacy and safety of once-weekly tirzepatide versus placebo alongside lifestyle intervention in Japanese adults with obesity or overweight.MethodsData from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed. Coprimary endpoints were mean percent change in body weight and the proportion of participants who achieved ≥ 5% body weight reduction at week 72.ResultsParticipants in the tirzepatide 5-, 10-, and 15-mg groups had a statistically significantly greater (all p < 0.001) least squares mean (standard error) percent change in body weight compared with those in the placebo group: -12.0% (1.7%), -22.4% (1.7%), -22.1% (1.6%), and -0.3% (1.6%), respectively. Overall, 91.7%, 100%, and 96.6% of participants in the tirzepatide 5-, 10-, and 15-mg groups, respectively, had ≥ 5% weight reduction at week 72, compared with 15.4% in the placebo group. Significant improvements in cardiometabolic measures were also observed with tirzepatide at week 72 compared to placebo. No new safety concerns were identified.ConclusionsOnce-weekly treatment with tirzepatide demonstrated significant reductions in body weight and prespecified cardiometabolic measures compared with placebo in Japanese adults with obesity or overweight.Trial registrationClinicalTrials.gov identifier: NCT04184622 https://clinicaltrials.gov/study/NCT04184622.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study8

8 results from studies that gave the peptide. 8 results from people.

01HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, once-weekly tirzepatide 5 mg reduced body weight by 12.0% versus 0.3% with placebo at week 72.
In plain wordsIn Japanese adults with obesity, tirzepatide 5 mg weekly led to more weight loss than placebo after 72 weeks.
Peptide
Tirzepatide
Outcome
DecreasePercent change in body weight at week 72
Study
n = 102
Comparator
Placebo
Analysis
Primary
Outcome group
Body weight · Metabolic and weight
Studied dose
5 mg once weekly · 72 weeksAs given in this study (human).
Measurements
Percent change in body weight tirzepatide 5 mg
−12%
week 72
Percent change in body weight placebo
−0.3%
week 72
Source sentences
Summary
Participants in the tirzepatide 5-, 10-, and 15-mg groups had a statistically significantly greater (all p < 0.001) least squares mean (standard error) percent change in body weight compared with those in the placebo group: -12.0% (1.7%), -22.4% (1.7%), -22.1% (1.6%), and -0.3% (1.6%), respectively.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296601
02HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, once-weekly tirzepatide 10 mg reduced body weight by 22.4% versus 0.3% with placebo at week 72.
In plain wordsIn Japanese adults with obesity, tirzepatide 10 mg weekly led to more weight loss than placebo after 72 weeks.
Peptide
Tirzepatide
Outcome
DecreasePercent change in body weight at week 72
Study
n = 102
Comparator
Placebo
Analysis
Primary
Outcome group
Body weight · Metabolic and weight
Studied dose
10 mg once weekly · 72 weeksAs given in this study (human).
Measurements
Percent change in body weight tirzepatide 10 mg
−22.4%
week 72
Percent change in body weight placebo
−0.3%
week 72
Source sentences
Summary
Participants in the tirzepatide 5-, 10-, and 15-mg groups had a statistically significantly greater (all p < 0.001) least squares mean (standard error) percent change in body weight compared with those in the placebo group: -12.0% (1.7%), -22.4% (1.7%), -22.1% (1.6%), and -0.3% (1.6%), respectively.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296602
03HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, once-weekly tirzepatide 15 mg reduced body weight by 22.1% versus 0.3% with placebo at week 72.
In plain wordsIn Japanese adults with obesity, tirzepatide 15 mg weekly led to more weight loss than placebo after 72 weeks.
Peptide
Tirzepatide
Outcome
DecreasePercent change in body weight at week 72
Study
n = 102
Comparator
Placebo
Analysis
Primary
Outcome group
Body weight · Metabolic and weight
Studied dose
15 mg once weekly · 72 weeksAs given in this study (human).
Measurements
Percent change in body weight tirzepatide 15 mg
−22.1%
week 72
Percent change in body weight placebo
−0.3%
week 72
Source sentences
Summary
Participants in the tirzepatide 5-, 10-, and 15-mg groups had a statistically significantly greater (all p < 0.001) least squares mean (standard error) percent change in body weight compared with those in the placebo group: -12.0% (1.7%), -22.4% (1.7%), -22.1% (1.6%), and -0.3% (1.6%), respectively.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296603
04HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, 91.7% on tirzepatide 5 mg had at least 5% weight reduction at week 72, versus 15.4% with placebo.
In plain wordsIn Japanese adults with obesity, 91.7% on tirzepatide 5 mg lost at least 5% of body weight, compared with 15.4% on placebo.
Peptide
Tirzepatide
Outcome
DecreaseProportion with at least 5% weight reduction at week 72
Study
n = 102
Comparator
Placebo
Analysis
Primary
Outcome group
Body weight · Metabolic and weight
Studied dose
5 mg once weekly · 72 weeksAs given in this study (human).
Measurements
Responders ≥5% weight reduction tirzepatide 5 mg
91.7%
week 72
Responders placebo
15.4%
week 72
Source sentences
Summary
Overall, 91.7%, 100%, and 96.6% of participants in the tirzepatide 5-, 10-, and 15-mg groups, respectively, had ≥ 5% weight reduction at week 72, compared with 15.4% in the placebo group.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296604
05HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, 100% on tirzepatide 10 mg had at least 5% weight reduction at week 72, versus 15.4% with placebo.
In plain wordsIn Japanese adults with obesity, all on tirzepatide 10 mg lost at least 5% of body weight, compared with 15.4% on placebo.
Peptide
Tirzepatide
Outcome
DecreaseProportion with at least 5% weight reduction at week 72
Study
n = 102
Comparator
Placebo
Analysis
Primary
Outcome group
Body weight · Metabolic and weight
Studied dose
10 mg once weekly · 72 weeksAs given in this study (human).
Measurements
Responders ≥5% weight reduction tirzepatide 10 mg
100%
week 72
Responders placebo
15.4%
week 72
Source sentences
Summary
Overall, 91.7%, 100%, and 96.6% of participants in the tirzepatide 5-, 10-, and 15-mg groups, respectively, had ≥ 5% weight reduction at week 72, compared with 15.4% in the placebo group.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296605
06HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, 96.6% on tirzepatide 15 mg had at least 5% weight reduction at week 72, versus 15.4% with placebo.
In plain wordsIn Japanese adults with obesity, 96.6% on tirzepatide 15 mg lost at least 5% of body weight, compared with 15.4% on placebo.
Peptide
Tirzepatide
Outcome
DecreaseProportion with at least 5% weight reduction at week 72
Study
n = 102
Comparator
Placebo
Analysis
Primary
Outcome group
Body weight · Metabolic and weight
Studied dose
15 mg once weekly · 72 weeksAs given in this study (human).
Measurements
Responders ≥5% weight reduction tirzepatide 15 mg
96.6%
week 72
Responders placebo
15.4%
week 72
Source sentences
Summary
Overall, 91.7%, 100%, and 96.6% of participants in the tirzepatide 5-, 10-, and 15-mg groups, respectively, had ≥ 5% weight reduction at week 72, compared with 15.4% in the placebo group.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296606
07HumanRandomized controlled trialEfficacy outcome
In Japanese adults with obesity, tirzepatide produced significant improvements in cardiometabolic measures compared with placebo at week 72.
In plain wordsIn Japanese adults with obesity, tirzepatide improved heart and metabolic measures more than placebo after 72 weeks.
Peptide
Tirzepatide
Outcome
Not applicableCardiometabolic measures at week 72
Study
n = 102
Comparator
Placebo
Outcome group
Cardiometabolic risk factors · Metabolic and weight
Studied dose
Dose not stated · 72 weeksAs given in this study (human).
Source sentences
Summary
Significant improvements in cardiometabolic measures were also observed with tirzepatide at week 72 compared to placebo.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296607
08HumanRandomized controlled trialSafety outcome
In Japanese adults with obesity, no new safety concerns were identified with tirzepatide.
In plain wordsIn Japanese adults with obesity, no new safety concerns were found with tirzepatide.
Peptide
Tirzepatide
Outcome
Not applicableSafety
Study
n = 102
Comparator
Placebo
Outcome group
Adverse events · Whole body
Studied dose
Dose not stated · 72 weeksAs given in this study (human).
Source sentences
Summary
No new safety concerns were identified.
1 context sentence(design, population, supporting numbers)
Summary · context
Data from 102 Japanese adults in the SURMOUNT-1 trial with BMI ≥ 30 kg/m² or ≥ 27 kg/m² and ≥ 1 weight-related comorbidity were analyzed.
Show in the study text Report a problemFND-4161296608

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Registered trials1

Trials this study reports on, or that list this study as a reference. Registry data from ClinicalTrials.gov.

1 trial · 1 completed · 1 with posted results · source ClinicalTrials.gov (opens in a new tab)

CompletedPhase 3Results postedNCT04184622

A Study of Tirzepatide (LY3298176) in Participants With Obesity or Overweight

Eli Lilly and Companyn = 2,5394 Dec 2019 to 6 Jul 2024

Overweight · Obesity

Trial page ClinicalTrials.govUpdated 24 Jul 2025

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
12 Oct 2026, 12:10 UTC
Study results updated
Version 1
9 Oct 2026, 03:07 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

PepBank is a research reference. Talk to a doctor before you use any peptide.