SAN DIEGO – Weight loss with tirzepatide was fairly uniform across different body mass index ranges, ages, and number of obesity-related comorbidities in patients with overweight/obesity without type 2 diabetes.
These were the main findings in a session about tirzepatide – the dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) agonist – for obesity, presented at the annual meeting of the Obesity Society.
In May, tirzepatide (Mounjaro), a once-weekly subcutaneous injection, was approved by the Food and Drug Administration for glycemic control in patients with type 2 diabetes based on the SURPASS clinical trials.
Then in June, at the American Diabetes Association 2022 annual meeting, researchers reported “unprecedented” weight loss with tirzepatide in patients without type 2 diabetes, in the phase 3 SURMOUNT-1 clinical trial.
In early October, the FDA granted fast track status (expedited review) to tirzepatide for use as an antiobesity drug.
Now these new analyses from SURMOUNT-1 show that “regardless of BMI, regardless of age, regardless of number of obesity-related complications, there was a clear dose-related weight loss that was pretty consistent across groups,” Session Chair Patrick M. O’Neil, PhD, who was not involved with this research, summarized.
“The absolute levels of these weight losses are higher than we’ve seen thus far with [antiobesity] medications,” added Dr. O’Neil, professor of psychiatry and behavioral sciences and director of the Weight Management Center at the Medical University of South Carolina, Charleston.
“Semaglutide took things up one big notch, and this is up a little notch above that,” he said in an interview.
“I’m a psychologist. It should be remembered that in all cases, the FDA approvals are predicated to using [drugs] as an adjunct to diet and exercise change as well,” he stressed.
“I don’t think people should expect that any medication that is currently available will have a lasting effect when it’s no longer taken,” he continued.
“We don’t expect any of these [antiobesity] medications to be making any permanent physiological changes,” Dr. O’Neil added, but patients could “use this medication to help themselves make some long-lasting behavioral changes, so that when they come off the medication, hopefully they’ll be able to continue these new patterns.
“Clearly the medications are having a significant impact,” he emphasized.
BMI, age, comorbidity subgroups, and overall QoL in SURMOUNT-1
SURMOUNT-1 compared the efficacy and safety of tirzepatide 5, 10, and 15 mg subcutaneous once-weekly to placebo, as an adjunct to a reduced-calorie diet and increased physical activity. The study included 2,539 adults without type 2 diabetes who had obesity (BMI ≥ 30 kg/m2) or overweight (BMI ≥ 27 kg/m2) with at least one obesity-related complication (hypertension, dyslipidemia, obstructive sleep apnea, or cardiovascular disease).
Age subgroups
Robert F. Kushner, MD, of Northwestern University, Chicago, noted that “Excessive lean mass loss is a clinical concern in elderly individuals being treated for obesity,” so it’s important to know if weight loss with tirzepatide differs by age.
The researchers performed a post hoc analysis in patients who had dual-energy x-ray absorptiometry (DXA) readings at baseline and week 72 (oral abstract 109).
The three age groups in the current analysis were < 50 years old (99 patients), ≥ 50 to < 65 years old (41 patients), and ≥ 65 years old (20 patients). Overall, 63% of patients were age < 50 years, 31% were age 50 to < 65 years, and 6% were ≥ 65 years.
At 72 weeks, patients taking 5, 10, and 15 mg/week tirzepatide lost 21.5%, 20.8%, and 22% of their initial body weight, respectively.
“Tirzepatide significantly lowered total body mass versus placebo regardless of age subgroups,” and it “consistently lowered fat mass, lean mass, fat-mass-to-lean-mass ratio, and visceral fat mass across age subgroups,” Dr. Kushner reported.