Zynerba Pharmaceuticals Inc. ZYNE, -2.63% shares plummeted 53% premarket on Monday after the company said its mid-stage clinical trial for cannabidiol gel in adult epilepsy with focal seizures didn't meet its primary endpoint or secondary endpoints. The company is working to evaluate the results and determine next steps. Zynerba Pharma emphasized that the therapy, ZYN002, had a "very favorable safety and tolerability profile," which was "encouraging" since the company plans to develop ZYN002 for a wide range of conditions. Data for the therapy in osteoarthritis are expected in August, and data from a trial in the genetic condition Fragile X syndrome are expected by the end of September. Company shares have dropped 21.7% over the last three months, compared with a 3.2% rise in the S&P 500 SPX, -1.11% .