Five patients taking part in a trial for a new drug for multiple sclerosis (MS) have seen "promising results", health officials have said.
The Norfolk and Norwich University Hospital is one of four centres in England taking part in the study.
Neurology research nurse Donna Clements said the patients have the relapsing-remitting form of the disease.
Since starting the trial two years ago, their rate of relapse has reduced significantly, she said.
MS is a neurological condition that affects the transfer of messages from the central nervous system to the rest of the body.
Ms Clements said: "All the patients involved in the study have the relapsing-remitting form of the disease and all were suffering relapses at least once a year before they started the clinical trial two years ago.
"Since then their rate of relapse has reduced significantly and some patients have not had any relapses at all."
Leading the study in Norfolk is consultant neurologist Dr Martin Lee, who is soon beginning a similar study for patients with primary-progressive MS, the most aggressive form of the disease.