The “Real World” Use Of Riluzole: Impressions Of Effectiveness From A Series Of 625 MND Patients

Objectives To review natural history data from a cohort of 625 motor neuron disease (MND) patients to gain further insights into the potential effectiveness of riluzole in ‘real world’ clinical practice. Methods A cohort of 625 MND patients seen in the Preston Neurology Department since 1980 were reviewed. Data on 150 patients lacked detail and were therefore excluded. Of the remaining 475 patients 148 received riluzole and 327 did not. Comparisons between these groups were made using statistical techniques including Kaplan Meier methodology and the log-rank test. Results Basic demographic details of the two groups were comparable (median onset age 61.06 riluzole, 65.10 non-riluzole; male/ female ratio 1.43 riluzole, 1.30 non-riluzole) although there was a higher proportion of bulbar onset patients in the nonriluzole group (bulbar/limb ratio 0.83 non-riluzole, 0.42 riluzole). Median survival in patients given riluzole (3.07 years) was longer than in untreated patients (2.25 years), hazard ratio (HR) 1.66 (95% CI 1.35–2.04). Corresponding results for limb onset patients were 3.61 (riluzole) and 2.63 (non-riluzole), HR 1.49 (95% CI 1.11–2.01) and for bulbar onset patients 2.19 (riluzole) and 1.84 (non-riluzole), HR 1.33 (95% CI 0.92–1.94). When gastrostomised patients were excluded the median survival was 3.51 years (riluzole) and 2.21 (non-riluzole), HR 1.91 (95% CI 1.51–2.41). Conclusions Clearly these data are based on retrospective analysis and fall short of the quality of data obtained from randomised controlled clinical trials (RCTs). RCTs of riluzole only showed modest efficacy and the need for further evaluation of the effectiveness of riluzole has been highlighted. 1 Following the widespread licensing of riluzole and its general use in MND patients further placebo controlled RCTs seem unlikely. Further insights into effectiveness will depend on retrospective or prospective observational studies. This study reinforces Poster Communications 185 Diagnosis, Prognosis and Disease Progressionthe RCT results and is consistent with other similar analyses of ‘real world’ clinical experience in suggesting a prolongation of median survival beyond that implied by the RCT evidence. We wondered if the increasing use of gastrostomy might have been a confounding influence in this study. The riluzole treated patients were seen in more recent years during a period when gastrostomy was also being increasingly used. This impression is not supported by the exclusion of gastrostomised patients from the analysis. Instead the apparent prolongation of median survival with riluzole was enhanced when gastrostomised patients were excluded. It is possible that the removal of the gastrostomised patients from the analysis biased the study towards longer surviving patients, thus raising the suggestion that riluzole might be more effective in longer survivors than in those whose disease progresses more rapidly. This does not however explain why the median survival in the patients not receiving riluzole (whole group 2.25, non-gastrostomised patients 2.21) were so similar.