Shionogi has announced the enrollment of the first patients in a global phase 2 clinical trial evaluating S-606001, an investigational oral therapy for adults with late-onset Pompe disease (LOPD). S-606001 is a substrate reduction therapy (SRT) designed to reduce glycogen production in muscle cells, addressing a key driver of disease progression.
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 randomized, double-blind, placebo-controlled trial evaluating the safety, pharmacodynamics, and preliminary efficacy of S-606001 as an add-on to standard ERT in adults with confirmed LOPD. The 52-week trial will be conducted across multiple sites in the United States, European Union, and United Kingdom, and is currently recruiting. As data from this trial emerge, they may help determine whether SRT can meaningfully improve clinical outcomes and reshape the standard of care in LOPD.
Source
Press release: https://www.shionogi.com/global/en/news/2026/03/20260319_11.html
Clinical trial: https://clinicaltrials.gov/study/NCT07123155