Tirzepatide Achieves Mean Weight Loss of 15.7% in SURMOUNT-2 Trial

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Data from the SURMOUNT-2 trial suggests use of tirzepatide (Mounjaro) was associated with superior weight loss compared to placebo therapy at 72 weeks, with patients losing up to 15.7% of their body weight in the trial.

With topline results announced by Eli Lilly and Company on April 27, 2023, results of the trial, which included adults with obesity or overweight and type 2 diabetes, indicate more than 80% of patients receiving tirzepatide 10 mg or 15 mg achieved a body weight reduction of 5% or greater.¹

"Obesity is a difficult-to-manage disease, and it's even more difficult for people living with type 2 diabetes," said Jeff Emmick, MD, PhD, senior vice president, product development at Eli Lilly and Company.¹ "The degree of mean weight reduction seen in SURMOUNT-2 has not been previously achieved in phase 3 trials for obesity or overweight and type 2 diabetes."

The announcement of SURMOUNT-2 results comes almost a year to the date after SURMOUNT-1 results were announced on April 28, 2022.² With SURPASS and SURMOUNT-1, tirzepatide flipped the world of obesity management upside down in 2022, with the aforementioned announcement followed by the release of trial results in June at the American Diabetes Association 82nd Scientific Sessions.³ In between the announcement and presentation, the agent would receive approval from the US Food and Drug Administration as an adjunct to diet and exercise for improving glycemic control in people with type 2 diabetes.⁴

In SURMOUNT-1, which examined 5, 10, and 15 mg formulations of tirzepatide in people with overweight and obesity, results indicated use of the once-weekly GIP/GLP-1 receptor agonist was associated with mean body weight changes of −15.0% (95% CI, −15.9 to −14.2), −19.5% (95% CI, −20.4 to −18.5), and −20.9% (95% CI, −21.8 to −19.9) with tirzepatide 5, 10, and 15 mg, respectively, compared to −3.1% (95% CI, −4.3 to −1.9) with placebo (P <.001 for all).³

A multicenter, randomized, double-blind, parallel, placebo-controlled trial, SURMOUNT-2 randomized 938 participants from 8 countries in a 1:1:1 ratio to receive tirzepatide 10 mg, tirzepatide 15 mg, or placebo. The trial was designed with a pair of coprimary endpoints, which were defined as the mean percentage change in body weight from baseline and the percentage of patients achieving a body weight reduction of 5% or more at 72 weeks.¹

Per trial protocol, all participants randomized to tirzepatide began the study at a dose of 2.5 mg tirzepatide once weekly and dosing was increased in a stepwise approach at 4-week intervals until the goal dose was achieved.¹

Upon analysis, results indicated use of tirzepatide was associated with mean weight changes of −13.4% (29.8 lb. or 13.5 kg) on 10 mg and −15.7% (34.4 lb. or 15.6 kg) on 15 mg compared to placebo (−3.3%, 7.0 lb. or 3.2 kg). Further analysis of the coprimary endpoints indicated 81.6% and 86.4% of those taking the 10 mg and 15 mg tirzepatide achieved a body weight reduction of at least 5% compared to just 30.5% of those taking placebo.¹

The release also pointed out 41.4% and 51.8% of people taking 10 and 15 mg tirzepatide, respectively, achieved at least 15% body weight reduction compared to 2.6% of those taking placebo. Additionally, results suggested the reduction in HbA1c observed in the trial were similar to those seen in the SURPASS trial.¹

The most common adverse events reported with tirzepatide 10 mg and 15 mg, respectively, were nausea (20.2%, 21.9%), diarrhea (19.9%, 21.5%), vomiting (10.9%, 13.2%) and constipation (8.0%, 9.0%). In safety analyses, discontinuation rates due to adverse events were 3.8%, 7.4%, and 3.8%for 10 mg tirzepatide, 15 mg tirzepatide, and placebo, respectively, with overall treatment discontinuation rates were 9.3%, 13.8%, and 14.9% for each of these groups.¹

Full results of SURMOUNT-2 are scheduled to be presented at the upcoming American Diabetes Association 83rd Scientific Sessions and will be submitted to a peer-reviewed journal. In their release, Eli Lilly and Company noted results from SURMOUNT-3 and SURMOUNT-4 are anticipated later this year. Based on these results, the company also plans to complete the US submissions for tirzepatide in adults with obesity or overweight with weight-related comorbidities in the coming weeks.¹

"The ADA Standards of Care recommends personalized weight loss goals for those with diabetes and obesity with maximum benefit seen with weight reductions as high as 15% (as seen here) are achieved. This further supports the role of tirzepatide in the treatment of individuals with type 2 and obesity. We are excited to see the full results of the SURMOUNT-2 study, which will be presented at the American Diabetes Association’s 83rd Scientific Sessions in June," said Robert Gabbay, MD, chief scientific and medical officer for the ADA, in a statement.

References:

1. Lilly's tirzepatide achieved up to 15.7% weight loss in adults with obesity or overweight and type 2 diabetes in surmount-2. Eli Lilly and Company. https://investor.lilly.com/news-releases/news-release-details/lillys-tirzepatide-achieved-157-weight-loss-adults-obesity-or. Published April 27, 2023. Accessed April 27, 2023.
2. Campbell P. Surmount-1 results tout tirzepatide's weight loss benefits. HCP Live. https://www.hcplive.com/view/surmount-1-results-tout-tirzepatide-s-weight-loss-benefits. Published April 28, 2022. Accessed April 27, 2023.
3. Campbell P. Surmount-1: Tirzepatide provides significant, sustained weight loss in obesity. HCP Live. https://www.hcplive.com/view/surmount-1-tirzepatide-provides-significant-sustained-weight-loss-in-obesity. Published June 4, 2022. Accessed April 27, 2023.
4. Campbell P. Tirzepatide (Mounjaro) wins FDA approval for type 2 diabetes. HCP Live. https://www.hcplive.com/view/tirzepatide-wins-fda-approval-for-type-2-diabetes. Published May 13, 2022. Accessed April 27, 2023.