This study focuses on people with Type 3 spinal muscular atrophy, a genetic condition that causes muscle weakness and affects movement ability. The research evaluates a new medication called NMD670, which works by affecting muscle channels to improve communication between nerves and muscles. The study aims to determine if this medication can help improve muscle strength and function in people who can walk.

The medication is given as tablets that participants take by mouth twice daily for 21 days. During the study, some participants will receive NMD670 tablets while others will receive placebo tablets. After a break period, participants who first received the study medication will switch to placebo, and those who started with placebo will receive NMD670. This type of study design helps researchers better understand how well the medication works.

The main focus is on measuring how far participants can walk in 6 minutes before and after taking the medication. The study also looks at other aspects of muscle function and strength, as well as the safety of the medication. Throughout the study, participants’ health will be monitored through various medical tests and examinations to ensure their safety and evaluate how well the treatment is working.