Cantor Fitzgerald analyst Elemer Piros downgraded bluebird bio to Sell from Hold and dropped his price target for the shares to $37 from $42. The biotech focused on developing gene therapies closed yesterday down 31c to $64.24. The analyst sees a lack of catalysts as he does not expect data to be announced at this year's American Society of Hematology conference to de-risk the hemoglobinopathy programs. Bluebird disclosed yesterday that all future LentiGlobin trials going forward will use its improved manufacturing process, and those trials are just beginning, Piros tells investors in a research note. As such, initial data on improved transduction efficiency may not become available until 2018, the analyst contends. With this year's ASH meeting not a catalyst, Piros expects selling pressure on bluebird shares.