 Pfizer Incs NYSE:PFE agreed acquisition of Arena Pharmaceuticals, Inc. NASDAQ:ARNA for almost double the closing price of the stock in the previous trading sessions, is just the latest case of big pharmas confidence to get into cannabinoid-based research, said the manager of an ETF focused on the sector. Nawan Butt, portfolio manager of The Medical Cannabis and Wellness UCITS ETC CBDX says it is also another example of the huge growth potential for the medical cannabis sector and how it is becoming more mainstream. 