This study is designed to evaluate whether a combination of N-acetylcysteine (NAC) and EH-301 can slow down or improve symptoms of amyotrophic lateral sclerosis (ALS). Researchers will assess changes in disease progression using the ALS Functional Rating Scale-Revised (ALSFRS-R), a standard tool for measuring daily functioning in people with ALS.

The main question is whether taking NAC together with EH-301 can prevent symptom worsening and possibly improve existing ALS symptoms.

Participants will be randomly assigned to receive either the active combination (NAC + EH-301) or matching placebos for 6 months. During this period, they will attend regular clinic visits for evaluations, tests, and safety monitoring.

After completing the initial 6-month phase, all participants may choose to join a 6-month open-label extension, where everyone receives the active treatment regardless of their original group.