Tolerability and Safety of Combined Glatiramer Acetate and N-Acetylcysteine in Relapsing-Remitting Multiple Sclerosis.

Introduction: Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system where inflammation and neurodegeneration play key roles. Mounting evidence implicates oxidative stress in the development of irreversible neuronal and glial injury in this condition. N-acetylcysteine (NAC) is a sulfhydryl amino acid derivative with antioxidant and antiapoptotic properties. Administration of NAC to mice attenuated the induction of or improved experimental autoimmune encephalomyelitis (an MS model).

Methods: We performed an open-label study to explore the tolerability and safety of the combination of glatiramer acetate (GA) and NAC in patients with relapsing-remitting multiple sclerosis at the outpatient MS clinics of the Jewish General Hospital and Hôpital Charles Lemoyne, Montreal, Canada. Seven patients with relapsing-remitting multiple sclerosis with at least one T1 gadolinium-enhancing lesion on screening magnetic resonance imaging were recruited. Treatment consisted of a 10-week run-in period followed by 36-week treatment with a combination of GA 20 mg subcutaneously once daily plus NAC 2.5 g orally twice daily. Outcome measures included safety and tolerability, redox biochemistry, and magnetic resonance imaging effect.

Results: Treatment with the combination of GA and NAC was safe and well tolerated.

Conclusions: In light of the favorable safety profile, an efficacy-demonstrating study may be considered.