* Interim analysis shows drug betters walking speed over 2 yrs
* 4 seizure related events reported in the trial
* Shares rise as much as 5 pct
Sept 10 (Reuters) - Acorda Therapeutics Inc (ACOR.O) said interim analysis of a late-stage trial of its experimental multiple sclerosis treatment, Fampridine-SR, showed that the drug improved walking speed in patients over a two-year period.
A total of 66 patients, or 24.9 percent of study participants, saw an average improvement of more than 30 percent in walking speed after 12 months of treatment and 22 percent after 24 months.
Fampridine-SR is an oral, sustained-release drug designed to improve walking ability in people with multiple sclerosis.
There were four seizure-related events reported in the trial, including one complex partial seizure and three patients with convulsion, the company said in a statement.
"This implies a seizure rate of 1.5 percent, which is in line with what would be expected from the general multiple sclerosis population," J.P. Morgan analyst Geoffrey Meacham said in a note.
It would have been great to see no seizures in the study, but this would be an unrealistic expectation for any multiple sclerosis study since multiple sclerosis predisposes to seizure risk, Meacham added.
He also said that apart from the seizure data, the safety profile for the drug, also known as MS-F203, looked clean and overall the data supports a regulatory approval.
Meacham reiterated his "overweight" rating on the stock.
Acorda shares the marketing rights to Fampridine with Biogen Idec Inc (BIIB.O), who acquired the rights to the drug outside the United States for an upfront payment of $110 million in July.
Hawthorne, New York-based Acorda is entitled to receive up to $400 million more if the drug meets certain regulatory and sales milestones.
Acorda shares were up 4 percent at $22.59 in morning trade on Nasdaq. They had touched a high of $22.76 earlier in the session. (Reporting by Esha Dey in Bangalore; Editing by Himani Sarkar)