bluebird bio to Present New Data from Clinical Studies of LentiGlobin™ Gene Therapy for Transfusion-Dependent β-thalassemia (TDT) and LentiGlobin Gene Therapy for Sickle Cell Disease (SCD) at the 24th EHA Congress

Additional follow-up from the completed Phase 1/2 Northstar (HGB-204)
study of LentiGlobin in adolescents and adults with TDT

New data from ongoing Phase 3 Northstar-2 (HGB-207) study of
LentiGlobin for TDT in patients who do not have β⁰/β⁰
genotype and Phase 3 Northstar-3 (HGB-212) of patients with β⁰/β⁰
genotype or an IVS-I-110 mutation

New data from ongoing Phase 1/2 HGB-206 study of investigational
LentiGlobin for patients with SCD

Company to hold conference call and webcast, Friday, June 14 at 8:00
a.m. EDT

CAMBRIDGE, Mass.–(BUSINESS WIRE)–bluebird
bio, Inc. (Nasdaq: BLUE) announced today that new data from its
investigational gene therapy programs for transfusion-dependent
β-thalassemia (TDT) and sickle cell disease (SCD) will be presented
during the 24th European Hematology Association (EHA) Congress in
Amsterdam, the Netherlands, June 13-16.

bluebird bio will present data from its clinical studies of LentiGlobin™
gene therapy for TDT including updated results up to 54 months from the
long-term follow-up period of the completed Phase 1/2 Northstar
(HGB-204) study. The company will also present new data from the ongoing
Phase 3 Northstar-2 (HGB-207) study in patients who do not have a β⁰/β⁰
genotype and from the ongoing Phase 3 Northstar-3 (HGB-212) study in
patients who have β⁰/β⁰ genotype or an IVS-I-110
mutation.

New data from the company’s Phase 1/2 HGB-206 study of LentiGlobin gene
therapy for SCD will include additional patients treated in the study
and updated data for those previously reported.

Oral Presentations: Transfusion-Dependent
β-Thalassemia

Results from the Phase 3 Northstar-3 Study Evaluating LentiGlobin
Gene Therapy in Patients with Transfusion-Dependent β-Thalassaemia and a
β⁰ or IVS-I-110 Mutation at Both Alleles of the
HBB Gene (HGB-212)
Presenting Author: Andreas Kulozik, M.D.,
Ph.D., University Hospital Heidelberg, Heidelberg, Germany
Date &
Time: Friday, June 14, 2019, 11:30 – 11:45 a.m. CEST (5:30 – 5:45 a.m.
EDT)

Clinical Outcomes of LentiGlobin Gene Therapy for
Transfusion-Dependent β-Thalassaemia (TDT) Following Completion of the
Northstar (HGB-204) Study
Presenting Author: Mark Walters,
M.D., Benioff Children’s Hospital, Oakland, Calif., U.S.
Date &
Time: Friday, June 14, 2019, 11:45 a.m. – 12:00 p.m. CEST (5:45 – 6:00
a.m. EDT)

Safety and Efficacy of LentiGlobin Gene Therapy in Patients with
Transfusion-Dependent β-Thalassaemia and Non-β⁰/β⁰
Genotypes in the Phase 3 Northstar-2 Study (HGB-207)
Presenting
Author: Franco Locatelli, M.D., Ph.D. University of Pavia, Pavia,
Lombardy, Italy
Date & Time: Sunday, June 16, 2019, 8:00 – 8:15
a.m. CEST (2:00 – 2:15 a.m. EDT)

Oral Presentation: Sickle Cell Disease

Updated Results from the HGB-206 Study in Patients with Severe Sickle
Cell Disease Treated Under a Revised Protocol with LentiGlobin Gene
Therapy Using Plerixafor-Mobilised Haematopoietic Stem Cells (HGB-206)
Presenting
Author: Julie Kanter, M.D., Division of Hematology and Oncology,
University of Alabama at Birmingham, Birmingham, Ala., U.S.
Date &
Time: Sunday, June 16, 2019, 8:15 – 8:30 a.m. CEST (2:15 – 2:30 a.m. EDT)

Abstracts outlining bluebird bio’s accepted data at EHA have been made
available on the EHA conference website.

Investor Event & Webcast Information

bluebird bio will host a conference call and live webcast at 8:00 a.m.
EDT Friday, June 14, 2019. To access the webcast, please visit the
“Events & Presentations” page within the Investors & Media section of
the bluebird bio website at http://investor.bluebirdbio.com/.
A replay of the webcast will be available on the bluebird bio website
for 90 days following the call.

About LentiGlobin for Transfusion-Dependent β-Thalassemia

In March 2019, the Committee for Medicinal Products for Human Use (CHMP)
of the European Medicines Agency (EMA) adopted a positive opinion
recommending conditional marketing authorization for LentiGlobin gene
therapy for TDT, which if approved will be commercialized as ZYNTEGLO™
(autologous CD34+ cells encoding β^A-T87Q-globin gene) gene
therapy for patients 12 years and older with transfusion-dependent
β-thalassemia (TDT) who do not have a β⁰/β⁰ genotype,
for whom hematopoietic stem cell (HSC) transplantation is appropriate
but a human leukocyte antigen (HLA)-matched related HSC donor is not
available. ZYNTEGLO adds functional copies of a modified form of the
β-globin gene (β^A-T87Q-globin gene) into a patient’s own
hematopoietic (blood) stem cells (HSCs). Once a patient has the β^A-T87Q-globin
gene they have the potential to produce HbA^T87Q, which is
gene therapy- derived-hemoglobin, at levels that significantly reduce or
eliminate the need for transfusions.

Non-serious adverse events (AEs) observed during clinical trials that
were attributed to ZYNTEGLO were hot flush, dyspnoea, abdominal pain,
pain in extremities and non-cardiac chest pain. One serious adverse
event (SAE) of thrombocytopenia was considered possibly related to
ZYNTEGLO.

Additional AEs observed in clinical studies were consistent with the
known side effects of HSC collection and bone marrow ablation with
busulfan including SAEs of veno-occlusive disease.

ZYNTEGLO continues to be evaluated in the ongoing Phase 3 Northstar-2
and Northstar-3 studies and the long-term follow-up study LTF-303. If
approved, ZYNTEGLO will be the first gene therapy to treat TDT.

About LentiGlobin for Sickle Cell Disease

LentiGlobin for sickle cell disease is an investigational gene therapy
being studied as a potential treatment to address the underlying genetic
cause of SCD. bluebird bio’s clinical development program for
LentiGlobin for SCD includes the ongoing Phase 1/2 HGB-206 study.

bluebird bio is conducting a long-term safety and efficacy follow-up
study (LTF-303) for people who have participated in bluebird
bio-sponsored clinical studies of LentiGlobin for TDT and LentiGlobin
for SCD. For more information visit: https://www.bluebirdbio.com/medical-professionals/our-clinical-trials/.

The European Medicines Association (EMA) granted Priority Medicines
(PRIME) eligibility and Orphan Medicinal Product designation to
LentiGlobin for the treatment of TDT. LentiGlobin for TDT was also part
of the EMA’s Adaptive Pathways pilot program, which is part of the EMA’s
effort to improve timely access for patients to new medicines.

The U.S. Food and Drug Administration granted Orphan Drug status and
Breakthrough Therapy designation to LentiGlobin for TDT; as well as
Orphan Drug status and Regenerative Medicine Advanced Therapy
designation for LentiGlobin for the treatment of SCD.

About bluebird bio, Inc.

bluebird bio is pioneering gene therapy with purpose. From
our Cambridge, Mass., headquarters, we’re developing gene therapies for
severe genetic diseases and cancer, with the goal that people facing
potentially fatal conditions with limited treatment options can live
their lives fully. Beyond our labs, we’re working to positively disrupt
the healthcare system to create access, transparency and education so
that gene therapy can become available to all those who can benefit.

bluebird bio is a human company powered by human stories. We’re putting
our care and expertise to work across a spectrum of disorders by
researching cerebral adrenoleukodystrophy, sickle cell disease,
transfusion-dependent β-thalassemia and multiple myeloma using three
gene therapy technologies: gene addition, cell therapy and
(megaTAL-enabled) gene editing.

bluebird bio has additional nests in Seattle, Wash.; Durham, N.C.; and
Zug, Switzerland. For more information, visit bluebirdbio.com.

Follow bluebird bio on social media: @bluebirdbio, LinkedIn, Instagram and YouTube.

ZYNTEGLO and LentiGlobin are trademarks of bluebird bio.

The full common name for ZYNTEGLO: A genetically modified autologous
CD34+ cell enriched population that contains hematopoietic stem cells
transduced with lentiviral vector encoding the β^A-T87Q-globin
gene.

Forward-Looking Statements

This release contains “forward-looking statements” within the meaning
of the Private Securities Litigation Reform Act of 1995. Any
forward-looking statements are based on management’s current
expectations of future events and are subject to a number of risks and
uncertainties that could cause actual results to differ materially and
adversely from those set forth in or implied by such forward-looking
statements. These risks and uncertainties include, but are not limited
to: the risk that our MAA submitted for LentiGlobin for TDT may not be
approved by the European Commission when expected, or at all; the risk
that the efficacy and safety results from our prior and ongoing clinical
trials of LentiGlobin for TDT will not continue or be repeated in our
ongoing or planned clinical trials of LentiGlobin for TDT; the risk that
the current or planned clinical trials of LentiGlobin for TDT will be
insufficient to support regulatory submissions or marketing approval in
the US and EU; the risk that the production of Hb^A-T87Q may
not be sustained over extended periods of time; and the risk that we may
not secure adequate pricing or reimbursement to support continued
development or commercialization of LentiGlobin for TDT following
regulatory approval. For a discussion of other risks and uncertainties,
and other important factors, any of which could cause our actual results
to differ from those contained in the forward-looking statements, see
the section entitled “Risk Factors” in our most recent Form 10-Q, as
well as discussions of potential risks, uncertainties, and other
important factors in our subsequent filings with the Securities and
Exchange Commission. All information in this press release is as of the
date of the release, and bluebird bio undertakes no duty to update this
information unless required by law.

Contacts

bluebird bio
Investors:
Elizabeth Pingpank, 617-914-8736
[email protected]

or

Media:
Catherine
Falcetti, 339-499-9436
[email protected]