A trial to assess the efficacy of glutamic acid in prevention of vincristine-induced neurotoxicity in pediatric malignancies: a pilot study.

Vincristine is considered as a backbone of therapy in the induction and consolidation phases of pediatric malignancies. Neurotoxicity is a principal side effect of its use. This study is a randomized single-blinded placebo-controlled clinical trial to evaluate the role of glutamic acid in ameliorating neurotoxicity in pediatric patients with hematologic and solid tumors receiving vincristine during induction course. Fifty-four patients in the glutamic acid group received glutamic acid 1.5 grams daily orally in 3 divided doses during the 4-week induction with vincristine in a dose of 1.5 mg/m² IV weekly. Placebo group (40 patients) received oral placebo 3 times daily in the same way as the glutamic acid group. The onset of neurotoxicity was significantly earlier in placebo group than in glutamic acid group regarding tendon Achilles reflex, Patellar reflex, parasthesia, and increased frequency of constipation. This was statistically significant mostly in third and fourth visits, no severe cases of strength and mental alteration side effects in both groups. Glutamic acid was well tolerated with no gastrointestinal side effects in patients. This study suggests that the coadministration of oral glutamic acid with repetitive intravenous bolus injections of vincristine resulted in a reduction of its neurotoxicity.