Overview
STEP-1 through STEP-4 trials established semaglutide's weight-management efficacy. Pivotal STEP-1 (NEJM 2021, PMID 33567185): 14.9% (treatment-policy estimand) mean weight loss at 2.4 mg / 68 weeks.
Questions readers ask
How much weight did people lose in STEP-1?
In STEP-1 (NEJM 2021, n=1,961), semaglutide 2.4 mg produced 14.9% mean weight loss at 68 weeks versus 2.4% on placebo, using the treatment-policy estimand. The trial was published in NEJM in 2021 (PMID 33567185).
What did STEP-2, STEP-3 and STEP-4 each study?
STEP-2 studied weight loss in people with type 2 diabetes, STEP-3 combined semaglutide with intensive behavioral therapy, and STEP-4 looked at maintenance after an initial period of weight loss.
How does STEP-1 compare with tirzepatide’s SURMOUNT-1 results?
STEP-1 showed −14.9% with semaglutide 2.4 mg at 68 weeks (treatment-policy estimand), while SURMOUNT-1 showed −20.9% with tirzepatide 15 mg at 72 weeks (treatment-regimen estimand). They were separate trials, so the figures are not a head-to-head comparison.
Which approval did the STEP program lead to?
STEP results led to Wegovy’s 2021 FDA approval for chronic weight management, at a maintenance dose of semaglutide 2.4 mg once weekly. Wegovy later gained a 2024 cardiovascular risk reduction indication based on the separate SELECT trial.