medwireNews: The substantial weight loss achieved with weekly semaglutide 2.4 mg is maintained if people continue to take the medication for 2 years, show the STEP 5 results.
“When interpreted together with the findings of the STEP 4 withdrawal trial and STEP 1 off-treatment extension study, which both showed weight regain after semaglutide discontinuation (after 20 weeks’ treatment in STEP 4 and 68 weeks’ treatment in STEP 1), these results support the benefit of continued semaglutide treatment for sustained weight loss,” write the investigators in Nature Medicine.
The STEP 5 participants had overweight or obesity, but not diabetes, with at least one weight-related comorbidity, and were predominantly White (93%) women (74–81%).
The average starting bodyweight in the 152 people randomly assigned to take semaglutide was 105.6 kg (BMI=38.6 kg/m2), and this reduced for about the first 60 weeks of semaglutide treatment, after which it plateaued to give an overall average weight reduction of 15.2% by week 104.
The average baseline bodyweight of the 152 people in the placebo group was 106.5 kg (BMI=38.5 kg/m2), which reduced by an average of 2.6% by week 104; both groups received a behavioral intervention to improve diet and physical activity for the duration of the trial.
The 12.6 percentage point difference between the groups at week 104 significantly favored semaglutide, and 77.1% of this group had lost at least 5% of their starting bodyweight at week 104, compared with 34.4% of the placebo group. The corresponding rates were 61.8% versus 13.3% for at least 10% bodyweight, 52.1% versus 7.0% for at least 15%, and 36.1% versus 2.3% for at least 20%.
Together with greater weight loss, people given semaglutide also had significantly larger improvements in variables such as waist circumference, blood pressure, and glucose and lipid levels.
“Collectively, these results indicate a beneficial effect of treatment on overall patient health,” say W Timothy Garvey (University of Alabama at Birmingham, USA) and STEP 5 co-investigators.
The safety profile of semaglutide during this 2-year trial was in line with that seen in shorter studies, they add.
Garvey and team note that, despite the overall large weight loss seen with semaglutide, a small number of participants actually gained weight, in line with findings from other studies.
“We do not know how weight would have changed in these participants had they not been receiving the drug,” say the researchers, stressing that “the proportion of patients with weight gain during the study was substantially higher in the placebo group.”
They conclude: “There is marked variability in weight change in patients on weight management treatments; the reason for this is still unclear and likely involves complex biological and societal influences.”
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Nat Med 2022; doi:10.1038/s41591-022-02026-4