Today Bluebird Bio (BLUE) tanked 37% after reporting trial data that left many analysts and investors mixed on sentiment. The new trial data was presented at the American Society of Hematology — ASH. In this ASH conference many biotech companies come together to present potentially promising data from trials for blood diseases. 

The trial data presented was from three patients who are using Bluebird’s Lentiglobin gene therapy to treat sickle cell disease. Two patients who have been followed for three and five months, respectively, have produced a small number of functioning red blood cells. It is too early to assess the 3rd patient in the study but preliminary data shows that patients also being a similar trend with the other two patients. 

This goes against the fact that Bluebird is stating that its Lentiglobin therapy is able to cure sickle cell disease. It has got one patient in a French study who has been followed for one year to clear the disease for the most part, and has been transfusion free. The problem is that in the U.S. HB-206 study similar results have not been achieved. 

Bluebird states that to achieve a function cure for sickle cell disease a patient must achieve at least an anti-sickling hemoglobin rate of 30%. The patient that was followed for three months had an anti-sickling hemoglobin rate of 13%. The five month patient had an anti-sickling hemoglobin rate of 15%. The French patient who responded very well achieved an anti-sickling hemoglobin rate of 49%. 

Investors dumped the stock today because of this mixed data. Investors were looking for the company to be a potential cure for sickle cell disease using its lentiglobin gene therapy. The hope with gene therapy is to replace defective genes with effective ones, in hopes of correcting the defect. In addition to the data, many analysts even posted downgrades, which also put further sell pressure on the stock. 

Roth, Bank of America and Merrill Lynch downgraded the stock down to Neutral from Buy. Morgan Stanley downgraded the stock down to equal weight from buy. The reason for the downgrades is that even if the sickle cell program is still successful it won’t be brought out as a cure. Therefore it is not expected to make as much money as if it was a cure. The share price of Bluebird had soared to a 52-week high of $197.35 on the hopes of being a cure for sickle cell disease and Beta Thalassemia.