S-606001 targets glycogen synthase 1 (GYS1), the enzyme responsible for glycogen production in muscle tissue. By inhibiting GYS1 activity, the therapy aims to reduce glycogen accumulation in muscle cells, which contributes to progressive muscle weakness and respiratory decline in Pompe disease. This mechanism is distinct from ERT, which focuses on increasing glycogen breakdown by supplementing deficient GAA. By targeting glycogen synthesis rather than degradation, S-606001 offers a complementary approach that may be used in combination with ERT or potentially as a standalone therapy in the future.
The ongoing phase 2 study (Esprit) is a randomised, placebo-controlled, double-blind trial investigating the safety, pharmacodynamics, and preliminary efficacy of S-606001 as an add-on to enzyme replacement therapy in adults with LOPD.
For more information:
Press release: https://www.shionogi.com/global/en/news/2026/03/20260319_11.html
Clinical trial: https://clinicaltrials.gov/study/NCT07123155