Intrathecal Administration of Riluzole in Amyotrophic Lateral Sclerosis.

Abstract

Riluzole is the only treatment known to improve survival in amyotrophic lateral sclerosis (ALS) patients. However, its efficacy and dosing are limited by hepatic toxicity and interindividual pharmacokinetic variability. Recent experimental studies in hounds have shown that continuous intrathecal (IT) administration of riluzole is well tolerated and achieves significantly higher spinal cord tissue levels. We report the first 2 human ALS cases treated with IT riluzole. A catheter was inserted into the lumbar cistern and advanced to the midcervical region under fluoroscopic guidance and connected to a subcutaneous pump. Therapy was initiated at 0.1 mg/h of riluzole. The infusion rate was gradually increased until it reached a maximum of 4.8 mg/d. The 2 patients tolerated dose escalation and treatment for over 2 years without apparent motor or sensory complications. Patients reported no asthenia, a central side effect often reported as a reason to abandon oral therapy. This is the first report of chronic IT riluzole infusion in humans at a dose found to be safe in canines. A phase 1 study is planned to establish the maximum tolerated human dose, followed by a randomized placebo-controlled trial to determine the safety and tolerability of IT riluzole in patients with ALS.