A randomized, double-blind, placebo-controlled, ascending-dose tolerability and safety study of remacemide as adjuvant therapy in Parkinson's disease with response fluctuations

The objective of this study was to establish the maximum tolerated dose of the low affinity non-competitive N-methyl-D-aspartate receptor antagonist remacemide in patients who have Parkinsons disease with response fluctuations or dyskinesias, or both. A total of 33 patients were randomly assigned in a 3-to-1 ratio to receive remacemide or placebo. Remacemide was administered orally at 150 mg twice daily, increasing incrementally by 100 mg (50 mg twice daily) at 2-week intervals to a final daily regimen of 400 mg twice daily or until a maximum tolerated dose was identified. The maximum total treatment period was 12 weeks. Of the 23 patients randomly selected to receive remacemide, four completed the study at the maximum permitted dose, compared with four of the 10 patients given placebo. The median maximum tolerated dose of remacemide was 450 mg/d. There was no clinically relevant change in percentage of "on" time between baseline and maximum tolerated dose in either group. At the maximum tolerated dose of remacemide for each patient, the mean Unified Parkinson's Disease Rating Scale (UPDRS) motor examination score (part III) decreased from 33 (SD 18) to 26 (SD = 13) compared with a decrease from 28 (SD = 12) to 27 (SD = 8) in the placebo group. There was a decrease in the mean UPDRS "complications of therapy" score (part IV) in the remacemide group from 8 (SD = 4) to 6 (SD = 4), and the placebo group remained unchanged at 6 (SD = 4). The most common adverse events associated with remacemide were nausea, vomiting, dizziness, headache, abnormal vision, and hypokinesia. Remacemide was well tolerated at a dose level of 400 mg/d. There was a trend suggesting that remacemide was effective in improving symptoms at patients' individual maximum tolerated doses. These improvements occurred without exacerbating levodopa-induced dyskinesias.