GW Pharmaceuticals Plc, a developer of cannabis-based medicines, said the U.K. will allow limited imports of its unlicensed multiple sclerosis drug, Sativex, from Canada. The shares jumped as much as 23 percent. Doctors and patients in the U.K. requested access to the cannabis-based medicine, GW said in a Regulatory News Service statement today. Shares in the Salisbury, England-based company rose 13.5 pence, or 19 percent, to 83.5 pence at 8:19 a.m. in London. They've fallen 31 percent this year.