STEP 1

In STEP 1, a phase 3 trial of semaglutide in adults with BMI of 30 or greater (27 or greater with at least one weight-related coexisting condition), without diabetes (n=1,961), mean body weight fell 14.9% on 2.4 mg over 68 weeks, against 2.4% on placebo (treatment-policy estimand; Wilding JPH et al. N Engl J Med 2021;384:989-1002).

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Updated 24 September 2026

Semaglutide Explained: STEP, SUSTAIN and SELECT Trials (Philippines)2:07Transcript and chapters

Results

Mean percent change in body weight by arm, as each source reports it. Navy bars are the trial arms, grey bars the comparator. Bars from different trials are not a head-to-head comparison: populations, durations and estimands differ.

Side effects reported

STEP 1: Discontinuation for adverse events is not given in the abstract; discontinuation for gastrointestinal adverse events was 4.5% against 0.8% on placebo.

Design

Trial design and sources

Compound: Semaglutide
Phase: 3
Population: Adults with BMI of 30 or greater (27 or greater with at least one weight-related coexisting condition), without diabetes
Participants randomised: 1,961
Duration: 68 weeks
Primary endpoint: Coprimary: percentage change in body weight and weight reduction of at least 5% (week 68)
Estimand: treatment-policy
Read out: 10 February 2021

Discontinuation for adverse events is not given in the abstract; discontinuation for gastrointestinal adverse events was 4.5% against 0.8% on placebo. The estimand is described in the abstract (effects regardless of treatment discontinuation or rescue) without being named.

Wilding JPH et al. N Engl J Med 2021;384:989-1002 open · checked 23 September 2026
ClinicalTrials.gov NCT03548935 open · checked 23 September 2026
Registry: NCT03548935

Questions

STEP 1, answered

What did STEP 1 find?

What side effects were reported in STEP 1?