Ongoing Semaglutide Treatment Extends Weight Loss in STEP 4

Mitchel L. Zoler, PhD

March 29, 2021

Weekly injections with the GLP-1 receptor agonist semaglutide helped people maintain, and even increase, their initial weight loss on the agent when they continued treatment beyond 20 weeks in results from an international, multicenter trial with 803 randomized subjects.

The study "reflects what we always see in practice, that when people lose weight their body then fights to regain it. The results underscore this" by showing what happens when people stop the drug, Domenica M. Rubino, MD, reported at the annual meeting of the Endocrine Society.

The STEP 4 study began with 902 obese or higher-risk people with an average body mass index of about 38 kg/m2 who underwent a 20-week, open-label, run-in phase of weekly subcutaneous injections of semaglutide (Ozempic), during which all subjects gradually up-titrated to the study's maintenance dosage of 2.4 mg/week and allowing investigators to weed out intolerant, noncompliant, or nonresponsive people. After this phase excluded 99 subjects from continuing, and documented that the remaining 803 patients had already lost an average of 11% of their starting weight, the core of the study kicked in by randomizing them 2:1 to either maintain their weekly semaglutide injections for another 48 weeks or change to placebo injections.

After 48 more weeks, the 535 people who continued active semaglutide treatment lost on average an additional 8% of their weight. Meanwhile, the 268 who switched to placebo gained 7% of the weight they had reached at the 20-week point, for a significant between-group weight-loss difference of about 15% for the study's primary endpoint. Those maintained on semaglutide for the full 68 weeks had a cumulative average weight loss of about 17%, compared with when they first began treatment, Rubino said. Concurrently with her report, the results also appeared in an article published online in JAMA.

"It's reassuring that people who remain on this treatment can sustain weight losses of 15%, and in some cases 20% or more. That's huge," Rubino said in an interview. . After 68 weeks, 40% of the people who maintained their semaglutide treatment had lost at least 20% of their weight, compared with when they first started treatment.

"Preventing weight regain following initial weight loss is a well-known major challenge for people who lose weight," commented John Clark III, MD, PhD, a weight management specialist at the University of Texas Southwestern Medical Center in Dallas who was not involved with the study. The findings from STEP 4 will be "helpful to have a discussion [with weight-loss patients] about the risks and benefits of continuing to take this medication longer than just a few months and if they want to continue taking the medication after they reach their goal weight," Clark noted in an interview. "This new information reinforces that treatment continues to be effective after the short term."

"This is obesity 101. If a treatment is provided that targets mechanisms of obesity, and then the treatment stops, we should not be surprised that weight regain occurs," commented Ania M. Jastreboff, MD, PhD, codirector of the Yale Center for Weight Management in New Haven, Conn. "It's tragic to see patients who, after successful weight loss, suffer regain because the treatment by which they lost weight stopped," she said in an interview.

The STEP 4 study ran at 73 centers in 10 countries during 2018-2020. It enrolled adults without diabetes and with a BMI of at least 30, or at least 27 if they also had at least one weight-related comorbidity such as hypertension, dyslipidemia, or obstructive sleep apnea. Participants averaged about 47 years of age, almost 80% were women, and about 84% were White, including 8% of Hispanic or Latinx ethnicity.

The adverse-event profile was consistent with findings from trials where semaglutide treated hyperglycemia in patients with type 2 diabetes (semaglutide at a maximum once-weekly dosage of 1 mg has Food and Drug Administration approval for controlling hyperglycemia in patients with type 2 diabetes), as well results from other semaglutide studies and from studies of other agents in the GLP-1 receptor agonist class.

In STEP 4 9% of patients who received semaglutide during the randomized phase and 7% of those randomized to placebo had a serious adverse reaction, and about 2% of those in both treatment arms stopped treatment because of an adverse event. The most common adverse events on semaglutide were gastrointestinal, with diarrhea in 14%, nausea in 14%, constipation in 12%, and vomiting in 10%.

These GI effects are often mitigated by slower dose escalation, eating smaller amounts of food at a time, and not eating beyond the point of feeling full, noted Jastreboff.

The STEP 4 results follow prior reports from three other large trials – STEP 1, STEP 2, and STEP 3 – that studied the weight-loss effects of weekly semaglutide treatment in adults using varying enrollment criteria and treatment designs. "We've seen very consistent results [across all four studies] for efficacy and safety," said Rubino, who owns and directs the Washington Center for Weight Management & Research in Arlington, Va.

NovoNordisk, the company that markets semaglutide, submitted data from all four studies to the FDA late last year in an application for a new label for a weight loss indication at the 2.4-mg/week dosage. The company has said it expects an agency decision by June 2021.

Rubino has been an adviser and consultant to and a speaker on behalf of Novo Nordisk, and she has also been an investigator for studies sponsored by AstraZeneca, Boehringer Ingelheim, and Novo Nordisk. Clark had no disclosures. Jastreboff is consultant for and has received research funding from NovoNordisk, and she has also been a consultant to and/or received research from Eli Lilly and Boehringer Ingelheim.

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