Biotech drug developer Acorda Therapeutics Inc. said Friday it will conduct an additional late-stage trial of its multiple sclerosis treatment based on feedback it received from a meeting with the Food and Drug Administration.

In September 2006, the company said its Fampridine-SR MS drug improved the walking speed in significantly more patients than a placebo in a late-stage clinical trial.

The trial was completed under a Special Protocol Assessment with the FDA, meaning Acorda sat down with officials to design a study that was most likely to yield the best results.

The FDA typically requires two well-controlled studies providing convincing results to substantially prove a drug is effective, according to the company.

Acorda said it will work with the agency to design the second study with a same or shorter duration than its previous late-stage trial.