Piper Jaffray analyst Tyler Van Buren downgraded Bluebird Bio to Neutral and cut his price target for the shares to $120 from $240. The stock closed Tuesday down $2.85 to $113.65. The company is "incredibly innovative" company and bb2121 and LentiGlobin are essentially curing some patients, but the benefits "are not without serious risks," Van Buren tells investors in a research note. And while these are risks worth taking for octorefractory multiple myeloma patients with just days to live, the proposition for beta thalassemia and sickle cell patients "is much more difficult," says the analyst. Further, Van Buren believes that as LentiGlobin launches next year, the "exuberance and hope" of clinical development will soon transition to "high expectations for commercial performance." Key opinion leaders agree that broad uptake of LentiGlobin will be challenging, admits the analyst. He lowered his estimates for LentiGlobin and downgraded Bluebird Bio to Neutral.