This clinical trial is focused on studying a disease called Amyotrophic Lateral Sclerosis (ALS), which affects nerve cells in the brain and spinal cord, leading to muscle weakness and loss of muscle control. The study is testing a new treatment called AP-101, which is a type of medication known as a monoclonal antibody. This medication is designed to target and neutralize harmful proteins in the body that may contribute to the progression of ALS. The trial will also use a solution called 0.9% Sodium Chloride for Injection as part of the study process.

The purpose of this study is to evaluate the safety and tolerability of AP-101 in patients with ALS. The study is divided into two phases: a double-blind phase, where neither the participants nor the researchers know who is receiving the actual medication or a placebo, and an open-label extension, where all participants receive the medication. During the study, participants will receive multiple doses of AP-101 through an intravenous (IV) injection over a period of six months. The study will monitor the participants’ health and any side effects that may occur.

Participants in the study will undergo regular health check-ups, including physical and neurological examinations, to ensure their well-being. The study will also measure certain markers in the blood and spinal fluid to understand how the body processes the medication. This research aims to gather important information that could lead to better treatments for ALS in the future.