RJK-002

The goal of this clinical trial is to evaluate the safety and efficacy of a single intrathecal injection of RJK002 in patients with Amyotrophic Lateral Sclerosis (ALS). The main questions it aims to answer are:
* The safety, tolerability, and preliminary efficacy of a single intrathecal injection of RJK002 in subjects with amyotrophic lateral sclerosis (ALS)
* The adeno-associated virus (AAV) viral load, changes of biomarkers in serum and cerebrospinal fluid (CSF), and electromyography (EMG) motor unit counts in subjects with ALS treated with a single intrathecal injection of RJK002.
Participants will receive a single intrathecal administration of investigational product and a systemic immunomodulatory regimen. There will be 3 cohorts: 6E13 vg/person (6 mL), 1.2E14 vg/person (12 mL), and 2.4E14 vg/person (24 mL). 3 subjects will be enrolled in each dose cohort. The dose level will be escalated sequentially from low to high.