SELLAS Life Sciences Group, Inc. (NASDAQ:SLS – Get Free Report) saw unusually large options trading on Friday. Traders bought 149,934 call options on the company. This is an increase of approximately 829% compared to the average volume of 16,138 call options. Get SELLAS Life Sciences Group alerts: Analyst Upgrades and DowngradesSeparately, Weiss Ratings restated a “sell (d-)” rating on shares of SELLAS Life Sciences Group in a research report on Wednesday, October 8th. One equities research analyst has rate ...