Why GW Pharmaceuticals (GWPH) Stock Hit a One-Year High Today

NEW YORK (TheStreet) -- GW Pharmaceuticals  (GWPH) surged to a 52-week high of $89.48 on Tuesday after the British biotech company reported positive safety and efficacy data from its epilepsy treatment drug Epidiolex.

The data from an efficacy group of 27 patients showed those who took the drug displayed a 44% median overall reduction in seizure frequency over 12 weeks. A total of 22% of patients had a 90% reduction and 15% had no seizures whatsoever. The data from a safety group of 62 patients showed at least one adverse event occurred in 81% of patients, though 80% of those events were mild to moderate.

The stock was up 13.93% to $88.01 at 12:58 p.m. More than 2.5 million shares had changed hands by that point, which surpassed the average volume of 876,645.

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