Associations between the ALSFRS-R score and urate levels during 12 months of edaravone treatment for amyotrophic lateral sclerosis: Post hoc analysis of ALSFRS-R scores in clinical studies MCI186-16, MCI186-17, and MCI186-19.

Abstract

In this study we examined the relationship between urate levels at baseline and functional change measured by the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) total score after edaravone treatment. Data from the edaravone trials MCI186-16, MCI186-17, and MCI186-19 were analyzed, including the following treatment sequence groups: edaravone-edaravone (EE, n=113); edaravone-placebo (EP, n=45); and placebo-edaravone (PE, n=146). Subgroups were defined as low baseline urate (below the median value of 4.8mg/dL) and high baseline urate (≥4.8mg/dL). The differences in ALSFRS-R total score change and urate change were evaluated using the mixed model for repeated measurement for overall population, by urate-level subgroup, and by trial. Compared with the PE group, the EE group showed a slower decline in ALSFRS-R score, regardless of the urate baseline level, and a slower decline in urate level in the higher baseline urate subgroup. Smaller changes in ALSFRS-R score and urate were observed in patients diagnosed with "probable, laboratory-supported ALS." There was a positive correlation between changes from baseline to cycle 12 in urate levels and ALSFRS-R score. Edaravone treatment in ALS patients diagnosed with "definite ALS" or "probable ALS" showed slowing of disease progression, regardless of baseline urate level. In addition, because edaravone treatment was associated with a slower decline in urate level in the higher baseline urate subgroup and urate-level changes were associated with changes in ALSFRS-R score, urate level, and/or change may be one indicator in predicting disease progression after edaravone administration.