- STEP UP randomized trial (n=1,407) evaluated once-weekly semaglutide 7.2 mg vs 2.4 mg vs placebo over 72 weeks in adults with obesity.
- Early responders (≥15% weight loss at week 24) were 26.9% on 7.2 mg and had mean 27.7% weight loss at week 72; 2.4 mg early responders (20.9%) averaged 24.8%.
- Body-composition MRI (n=55) found 84% of lost weight was fat, visceral fat reduced >30%, muscle mass fell ~10% while functional strength was maintained.
STEP UP trial design and topline results
The 72-week, randomized, double-blind STEP UP trial enrolled 1,407 adults with BMI ≥30 kg/m2 without diabetes to compare once-weekly semaglutide 7.2 mg, 2.4 mg and placebo as adjuncts to lifestyle intervention; mean weight loss at week 72 was 21.0% for 7.2 mg, 17.5% for 2.4 mg and 2.4% for placebo, with a safety and tolerability profile for 7.2 mg consistent with 2.4 mg.
Responder timing and magnitude
Early responders (≥15% weight loss by week 24) comprised 26.9% on 7.2 mg, 20.9% on 2.4 mg and 3% on placebo; early responders on 7.2 mg averaged 27.7% weight loss at week 72 versus 24.8% for 2.4 mg, while responders excluding early responders averaged 15.4% (7.2 mg) and 13.2% (2.4 mg).
Body composition and muscle function
An MRI sub-analysis (n=55) showed 84% of semaglutide-related weight loss (pooled 2.4 and 7.2 mg) was fat mass, abdominal visceral fat declined >30%, muscle mass fell ~10% from baseline but intramuscular fat decreased and functional muscle strength (30-second sit-to-stand) was maintained.
Additional trial program
STEP UP T2D was a 72-week, randomized trial of semaglutide 7.2 mg in 512 adults with obesity and type 2 diabetes.
