CHICAGO – compared with placebo, while causing modest increases in heart rate, in a prespecified substudy of the SURMOUNT-1 trial.
“The large effects on ambulatory 24-hour blood pressure raise the possibility that there may be important long-term benefits of [tirzepatide] on the complications of obesity,” said James A. de Lemos, MD, during a presentation at the American Heart Association scientific sessions.
Mitchel L. Zoler/MDedge News
Dr. James A. de Lemos
“The findings are concordant with the [previously reported] office-based measurements, and the blood pressure reductions provide further evidence for the potential benefits of tirzepatide on cardiovascular health and outcomes,” said Dr. de Lemos, a cardiologist and professor at the University of Texas Southwestern Medical Center, Dallas.
The substudy included 600 of the 2,539 people enrolled in SURMOUNT-1, the first of two pivotal trials for tirzepatide (Mounjaro) in people without diabetes but with obesity or overweight (body mass index of 27-29 kg/m2) plus at least one weight-related complication. The primary endpoints of SURMOUNT-1 were the percent change in weight from baseline to 72 weeks on treatment with either of three different weekly injected doses of tirzepatide, compared with control subjects who received placebo, and the percentage of enrolled subjects achieving at least 5% loss in baseline weight, compared with the controls.
Tirzepatide treatment led to significant increases in both results, compared with controls, with the highest dose tested, 15 mg/week, resulting in an average 20.9% drop in weight from baseline after 72 weeks of treatment, and 91% of enrolled subjects on that dose achieving the 5% weight-loss threshold during the same time frame, in results published in 2022 in the New England Journal of Medicine.
24-hour ambulatory pressures from 494 people
The substudy enrolled 600 of the SURMOUNT-1 participants and involved 24-hour ambulatory BP and heart rate measurements at entry and after 36 weeks on treatment. Full results were available for 494 of these people. The substudy included only study participants who entered with a BP of less than 140/90 mm Hg. Enrollment in SURMOUNT-1 overall excluded people with a BP of 160/100 mm Hg or higher. The average BP among all enrolled participants was about 123/80 mm Hg, while heart rates averaged about 73 beats per minute.
Systolic BP measured with the ambulatory monitor fell from baseline by an average of 5.6, 8.8, and 6.2 mm Hg in the people who received tirzepatide in weekly doses of 5, 10, or 15 mg, respectively, and rose by an average 1.8 mm Hg among the controls, Dr. de Lemos reported. Diastolic BP dropped among the tirzepatide recipients by an average of 1.5, 2.4, and 0.0 mm Hg in the three ascending tirzepatide treatment arms, and rose by an average 0.5 mm Hg among the controls. All of the differences between the intervention groups and the controls were significant except for the change in diastolic BP among participants who received 15 mg of tirzepatide weekly.
The results showed that 36 weeks on tirzepatide treatment was associated with “arguably clinically meaningful” reductions in systolic and diastolic BPs, Dr. de Lemos said. “There is a lot of optimism that this will translate into clinical benefits.” He also noted that, “within the limits of cross-study comparisons, the blood pressure changes look favorable, compared with the single-incretin mechanism GLP-1 [glucagonlike peptide–1] receptor agonists.”
Heart rate fell by an average 1.8 bpm in the controls, and rose by an average 0.3, 0.5, and 3.6 bpm among the three groups receiving ascending weekly tirzepatide doses, effects that were “consistent with what’s been seen with the GLP-1 receptor agonists,” noted Dr. de Lemos.
Tirzepatide is known as a “twincretin” because it shares this GLP-1 receptor agonism and also has a second incretin agonist activity, to the receptor for the glucose-dependent insulinotropic polypeptide.