A pioneering stem cell treatment for patients disabled by stroke has continued to show long-term promise in a clinical trial, the British biotech company behind the project said on Friday. 

News that two-year follow-up data from a small Phase I study showed improvements in limb function with no worrying safety issues lifted shares in ReNeuron 10 percent by 0830 EDT.

The clinical results were presented at the European Stroke Organisation Conference in Glasgow.

The company said there had been no cell-related or immunological adverse events in any of the 11 patients treated. The only problems seen were related only to the implantation procedure or the patient's underlying medical condition.

Improvements in neurological status and limb function were observed within three months of treatment and maintained throughout long-term follow-up.

The procedure involves injecting ReNeuron's neural stem cells into patients' brains to repair areas damaged by stroke, thereby improving both mental and physical function.

The Phase I trial is designed primarily to test whether the experimental treatment is safe.