Changes in lean body mass in all regions of the body apart from the arms are significantly correlated with percent change from baseline in the 4-stair climb test at week 97 in boys with Duchenne muscular dystrophy (DMD), according to a new study published in the journal Scientific Reports.

The percent lean mass derived from dual-energy X-ray absorptiometry (DXA) at week 49 correlates with the 4-stair climb test and North Star Ambulatory Assessment at week 97, Sarah P. Sherlock, of Pfizer in Boston, Massachusetts, and colleagues noted.

“These data indicate that whole-body DXA measures can be used as biomarkers for treatment effects and disease progression in patients with DMD, and warrant further investigation,” the study authors wrote. 


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The study consisted of a post hoc analysis of data from a phase 2, randomized, double-blind, placebo-controlled, clinical trial of domagrozumab and placebo in 120 patients with DMD who did not require a wheelchair.

Results from the trial showed that domagrozumab treatment significantly increased lean body mass in the upper and lower extremities, including the shoulder girdle and pelvis, as well as the arms, compared to the placebo.

When they evaluated the relationship between lean body mass at week 49 and functional endpoints at week 97, the researchers found a significant correlation.

The authors said that this correlation “suggest[s] that DXA changes could precede functional changes.”

DXA is a method to quantify body composition, including both fat mass and lean body mass, as a substitute measure of skeletal muscle.

DMD is a recessive X-linked disease caused by a mutation in the DMD gene, which codes for the dystrophin protein. In the absence of dystrophin, muscle damage occurs at each contraction leading to weakness and wasting. Muscle weakness affects the proximal muscles first and then moves onto the distal muscles.

Reference

Sherlock S, Palmer J, Wagner K, et al. Dual-energy X-ray absorptiometry measures of lean body mass as a biomarker for progression in boys with Duchenne muscular dystrophy. Sci Rep. Published online November 5, 2022. doi:10.1038/s41598-022-23072-5