Elan, the Irish drugs firm, says that analysis from phase three trials of its MS drug Tysabri shows that the drug increases the probability of patients achieving sustained improvement in physical disability over two years. The firm reported no new cases of the PML brain disease. However, one patient with the disease is reportedly recovering and one deteriorating further.

The Athlone-based company that was founded by American Don Panoz, said this is the first evidence that Tysabri is associated with a significant improvement in functional outcome, rather than only slowing the progression of disability.

Elan announced the development at a presentation at the World Congress on Treatment and Research in Multiple Sclerosis in Montreal, Canada.

"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."said Frederick E. Munschauer, MD, Smith Professor and Chair, Department of Neurology, State University of New York at Buffalo."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."

Jack Gorman, analyst at Irish broker Davy commented today:"The PML patient update at the MS World Congress revealed mixed news – with one patient reportedly recovering and one deteriorating further. However, no new PML cases were confirmed, and the fact that Tysabri patient numbers have continued to increase indicates that at least initially the risk/benefit balance for many patients is still in favour of the ELN/BIIB drug.

The PML patient updates are important given that they may indicate how useful early intervention with plasmaphoresis may be. In this respect, the Swedish patient case is encouraging – the patient is recovering and is suffering from only mild weakness on one side of the body. PML was originally diagnosed in this patient within one month.

The second more severe patient case in Germany has deteriorated and is close to a coma. The patient had previously been treated with other MS therapies and azathriopine, and the complex nature of the case meant that PML was not diagnosed until at least three months after developing the disease. Thus higher levels of the virus were in the brain before intervention occurred."

By the end of June, 31,800 people worldwide were using Tysabri.

Elan's share price is up 3.93% in Dublin, while the overall ISEQ Index is down 0.97%.

Irish Share Prices