Athlone-based Elan has claimed that a post-hoc analysis showed that its controversial multiple sclerosis drug Tysabri increases the probability of achieving sustained improvement in physical disability over two years when compared to a placebo.
The company said in a statement to the stock exchange this week that this post-hoc analysis provides the first evidence that Tysabri is associated with a significant improvement in functional outcome, rather than only slowing or preventing progression of disability, in those living with relapsing multiple sclerosis (MS ).
“These findings were derived from a subset analysis of the Phase III Affirm trial and were presented Monday as a poster presentation at the World Congress on Treatment and Research in multiple sclerosis in Montreal, Canada.
According to Frederick E. Munschauer, MD, Smith Professor and Chair, Department of Neurology, State University of New York at Buffalo, these results show that Tysabri-treated patients are significantly more likely to experience a sustained improvement in disability compared to placebo patients.
“This finding from a post-hoc analysis of the pivotal Affirm trial supports both the earlier findings from the Affirm trial that Tysabri is associated with an improvement in quality of life as well as anecdotal evidence of recovery of function in some patients.
"While, like TYSABRI, other therapies have shown a slowing of progression in disability, this analysis represents the first evidence supporting a sustained improvement in function associated with an approved disease modifying therapy."
Elan said the proportion of patients exhibiting sustained improvements in physical disability in the Affirm study was determined based upon the Expanded Disability Status Scale (EDSS ) over two years in patients with relapsing MS. EDSS is one of the oldest and most widely utilised methods of quantifying disability in MS.
Post-hoc analysis of Affirm patients assessed sustained improvement in disability among patients with a baseline EDSS score 2.0. Improvement in disability was defined as a one-point decrease in EDSS score sustained for 12 weeks.
The cumulative probabilities of 12-week sustained improvement in disability at two years were estimated using the Kaplan-Meier method.
Treatment effects were analysed using the Cox proportional hazards model adjusted for baseline EDSS score. The distribution of sustained improvement by baseline EDSS score for each treatment group was also examined, the statement added.