bluebird bio to Present LentiGlobin Clinical Data at 20th Congress of European Hematology Association

bluebird bio, Inc.

, a clinical-stage company committed to developing potentially transformative gene therapies for severe genetic and rare diseases and T cell-based immunotherapies, today announced that data from the ongoing Phase 1/2 HGB-205 study of LentiGlobin BB305 Drug Product will be presented in an oral presentation on June 13, 2015 at the 20th Congress of the European Hematology Association (EHA) in Vienna, Austria. "The early data included in our abstract provide further validation for our approach and important insights into the safety and mechanism of action of LentiGlobin in both beta-thalassemia and sickle cell disease," said David Davidson, chief medical officer, bluebird bio. "As noted in the abstract, we are pleased to report that the two patients with beta-thalassemia major, on whom we first reported last year at EHA, remained transfusion independent at 14 and 11 months post-transplant. In addition, it is very encouraging that the patient with sickle cell disease is increasing production of HbAT87Q, which has anti-sickling properties, and has not had a post-treatment hospitalization for a sickle cell disease-related event. At EHA we will present further follow up data on all three subjects." Abstract Highlights (Data as of February 2015): Beta-thalassemia: Beta-thalassemia major subjects (1201 and 1202) remained transfusion independent at 14 months and 11 months, respectively Sickle Cell Disease: This subject (1204) entered the trial receiving chronic transfusions and began the process of being weaned from transfusions after day 37, receiving the last transfusion on day 88 Increasing production of HbAT87Q; the first-ever SCD patient treated with gene therapy (subject 1204) had a HbAT87Q level of 24% at 4.5 months follow up, compared to an HbAT87Q level of 9.6% at three months post-transplant Note that this subject did not engraft until after month one, so their level of HbAT87Q production at months three and 4.5 are actually months two and 3.5, after engraftment At 4.5 months follow up, total anti-sickling hemoglobin (HbAT87Q + HbF) was 31.6% Subject 1204 has not had any hospitalizations for SCD-related complications post-transplant Safety: No subject has experienced a drug product-related adverse event, and integration site analyses demonstrate highly polyclonal reconstitution without clonal dominance Based on historical clinical observations in patients with SCD, bluebird bio believes that individuals who achieve ≥ 30 percent of anti-sickling hemoglobin (HbAT87Q + HbF) have the potential to reduce or eliminate the serious and life-threatening events associated with SCD. The abstract is now available online on the EHA conference website. Information contained in the abstract reflects data available as of February 2015. Details of bluebird bio's presentation are as follows: Title: Outcomes of Gene Therapy for B-Thalassemia Major and Severe Sickle Cell Disease via Transplantation of Autologous Hematopoietic Stem Cells Transduced Ex Vivo with a Lentiviral Beta Globin Vector Abstract Code: S466 Session Name: Gene therapy, cellular immunotherapy and vaccination Date: Saturday, June 13, 2015 Oral Presentation Time: 11:30 - 11:45 a.m. CET Location: Reed Messe Vienna, Room Stolz 2 Investor Conference Call and Webcast Information bluebird bio will host a conference call and webcast on June 15, 2015 at 8:00 a.m. ET to discuss the full data presented at EHA. The event will be webcast live and can be accessed under "Calendar of Events" in the Investors and Media section of the company's website at www.bluebirdbio.com. Alternatively, investors may listen to the call by dialing (844) 825-4408 from locations in the United States and (315) 625-3227 from outside the United States.