Overview
- The randomized, double‑blind phase 2 trial, published Monday, June 8, gave 102 adults monthly infusions of apitegromab or placebo while all participants received weekly tirzepatide for 24 weeks.
- Apitegromab, which blocks activation of myostatin (a protein that limits muscle growth), preserved roughly 1.6–1.9 kg of lean body mass and achieved about 54.9% relative retention versus placebo.
- Overall weight loss and fat loss were similar between groups, showing the antibody did not blunt tirzepatide’s effect on total weight reduction.
- The trial found no clear improvements in measured strength, physical function, or cardiometabolic markers over 24 weeks, and most participants experienced mild adverse events while serious events were rare.
- Apitegromab is investigational, delivered by monthly IV infusion, and experts say larger, longer, and more diverse studies with objective functional and metabolic endpoints are required before regulatory review or routine clinical use.