The finding

German cohort of Spinraza-treated adults (n = 9, age 31-66, median 4.5-year follow-up) shows quantitative whole-body MRI detects muscular fat fraction (mFF) changes that clinical tests miss. Source: SMA News Today 2026-04-08, European Journal of Neurology 2026.

Why it matters

Adult SMA trials have been rate-limited by insensitive outcome measures — HFMSE ceiling effects make long-term progression hard to detect, and studies need 3+ years to find a signal. qMRI-derived mFF is:

• Objective, not effort-dependent
• Sensitive to slow progression even at plateau HFMSE
• Reproducible across sites

If validated in a larger cohort, this is a trial-design enabler for every muscle-directed adjunct (apitegromab, taldefgrobep, ARGX-119) and for the NRF2/KEAP1 redox axis work — all of which need longitudinal biomarkers to show effect within a 2-year trial window.

In-platform

Added to our biomarker watchlist. Will cross-link to /calibration once we have a matching outcome-certainty entry.