Tirzepatide once weekly for the treatment of obesity

New England Journal of Medicine·2022·Jastreboff AM, Arslanian SA, Jones LE, et al.·New England Journal of Medicine

This landmark Phase 3 trial (SURMOUNT-1) evaluated tirzepatide, a dual GLP-1 and GIP receptor agonist, in adults with obesity. Participants achieved up to 22.5% mean weight reduction at 72 weeks, among the highest reported for a pharmacological agent in a registrational trial.

Why this research is interesting

Tirzepatide has become a reference point for dual receptor agonism in metabolic medicine. This registrational trial provides some of the strongest clinical evidence for the approach, making it essential reading for understanding the current landscape of incretin-based therapies.

What the research says

The SURMOUNT-1 trial randomized over 2,500 adults with obesity to receive tirzepatide or placebo over 72 weeks. At the highest dose, mean weight reduction reached 22.5%, with a substantial proportion of participants achieving 20% or greater weight loss.

What the evidence shows

This is a Phase 3 randomized controlled trial with a large sample and long duration. It represents high-quality clinical evidence. However, it used placebo rather than an active comparator, and longer-term outcomes beyond 72 weeks are still being studied.

What remains uncertain

Maintenance of weight loss after treatment cessation, real-world adherence patterns, long-term cardiovascular outcomes, and effects in populations with specific comorbidities require further study.