Zynerba Pharma’s failed cannabidiol gel trial has upside for rival GW Pharma By: MarketWatch August 07, 2017 at 11:01 AM EDT GW Pharma’s Epidiolex could be the U.S.’s first cannabis-derived drug. Read More >> Related Stocks: Gw Pharma ADR Standard & Poors 500 Zogenix Inc Zynerba Pharma CS