Pharma giant Pfizer Inc. recently announced it would buy Trillium Therapeutics Inc. in a deal valuing the Mississauga blood cancer drug developer at US$2.26-billion. Pfizer invested US$25-million last year in Trillium, picking up 2.3 million shares. It’s the second-largest deal for a Canadian biotech company on record, after Shire Pharmaceuticals Group PLC’s $5.9-billion CAD purchase of AIDS drug developer BioChem Pharma Inc. 20 years ago.