Long-Term Safety and Efficacy Data of Extended Half-Life Therapy ALPROLIX® in Children with Hemophilia B Published in The Lancet Haematology

Pediatric Findings Align with Adult/Adolescent Study Results of
ALPROLIX

WALTHAM, Mass. & STOCKHOLM–(BUSINESS WIRE)–Bioverativ
Inc. (NASDAQ: BIVV) and Swedish
Orphan Biovitrum AB (publ) (Sobi™) (STO: SOBI) today announced that
results from the Kids B-LONG Phase 3 clinical trial, which studied
ALPROLIX® [Coagulation Factor IX (Recombinant), Fc Fusion Protein] in
previously-treated children with severe hemophilia B, were published in The
Lancet Haematology. The primary outcome measure of the trial was
development of inhibitors, and no patients treated with ALPROLIX in the
study developed inhibitors. Treatment was generally well tolerated and
resulted in low bleeding rates in participants, most of whom remained on
once-weekly dosing during the study. The manuscript, entitled “Recombinant
Factor IX Fc Fusion Protein in Children with Haemophilia B (Kids
B-LONG): Results from a Multicentre, Non-Randomised Phase 3 Study,”
was published in the February
2017 issue of The Lancet Haematology.

“The Medical and Scientific Advisory Council of the National Hemophilia
Foundation recommends that prophylaxis be considered the optimal
treatment regimen for people with severe hemophilia B, and be initiated
early based on the body of evidence demonstrating improved long-term
clinical outcomes,” said Roshni Kulkarni, MD, Department of Pediatrics
and Human Development, Michigan State University, East Lansing,
Michigan, United States, and investigator in the study. “To date, Kids
B-LONG is the largest study to evaluate the safety and efficacy of
extended half-life factor IX therapy in children with hemophilia B, and
the study’s results align with those in studies of ALPROLIX in adults
and adolescents.”

Kids B-LONG investigated the safety, efficacy and pharmacokinetics
(measurement of the presence of the drug in a person’s body over time)
of ALPROLIX in previously treated children under the age of 12 with
severe hemophilia B (n=30). The primary outcome measure was development
of inhibitors (neutralizing antibodies that can interfere with the
activity of the therapy). Secondary outcomes included pharmacokinetics,
annualized bleeding rate (ABR), and the number of infusions required to
resolve a bleed.

In this study, no participants developed inhibitors to ALPROLIX.
ALPROLIX was well tolerated and adverse events (AEs) observed were
typical of the pediatric hemophilia B population. The most common AEs
were common cold (n=7, 23%) and fall (n=6, 20%). Four participants
experienced serious AEs during the study, all of which were assessed as
unrelated to ALPROLIX by the investigators. In the study, there were no
reports of anaphylaxis or serious hypersensitivity reactions to
ALPROLIX, no vascular thrombotic events, and no deaths.

Children (n=30) treated prophylactically with ALPROLIX had a median ABR
of 2.0 overall and zero spontaneous joint bleeds. Of all patients
treated, 10 of 30 (33%) experienced no bleeding episodes, and 19 of 30
(63%) reported no joint bleeding on-study. Overall, 92% of bleeding
episodes were controlled by one or two infusions of ALPROLIX. Following
a switch to ALPROLIX therapy, 80% of children extended their dosing
interval compared to previous treatment, and nearly all remained on
once-weekly prophylactic dosing throughout the study.

“These data in children reaffirm the well-characterized efficacy and
safety profile of ALPROLIX as demonstrated in studies of adults and
adolescents with hemophilia B, and they build on the robust real-world
experience of ALPROLIX over more than two years,” said Maha
Radhakrishnan, MD, senior vice president of medical at Bioverativ.
“Together with Sobi, we are committed to advancing the care of people
with hemophilia around the world.”

“Through Fc fusion technology, ALPROLIX uses the body’s natural pathway
to prolong the time the therapy remains in the body,” said Krassimir
Mitchev, MD, PhD, vice president and medical therapeutic area head of
haemophilia at Sobi. “Along with Bioverativ, we are dedicated to
furthering the study of real-world clinical use of ALPROLIX and
continuing to explore the potential of Fc fusion technology to address
the significant unmet needs that remain in hemophilia.”

About Kids B-LONG
Kids B-LONG was a global, open-label,
multicenter Phase 3 study involving 30 boys under the age of 12 with
severe hemophilia B (factor IX activity equal to or less than 2 IU per
dL, or 2%) with at least 50 prior exposure days to factor IX therapies.
To date, Kids B-LONG is the largest study to evaluate extended half-life
factor IX therapy in children with hemophilia B. The study was conducted
at 16 hemophilia treatment centers in Australia, Hong Kong, Ireland, the
Netherlands, South Africa, the UK, and the United States. Overall, 27
participants (90%) completed the study. The median time participants
spent in the study was 49.4 weeks, and 24 participants received ALPROLIX
infusions on at least 50 separate days (exposure days).

About ALPROLIX®
ALPROLIX® [Coagulation Factor IX
(Recombinant), Fc Fusion Protein], is a recombinant clotting factor
therapy developed for hemophilia B using Fc fusion technology to prolong
circulation in the body. It is engineered by fusing factor IX to the Fc
portion of immunoglobulin G subclass 1, or IgG1 (a protein commonly
found in the body), enabling ALPROLIX to use a naturally occurring
pathway to extend the time the therapy remains in the body (half-life).
While Fc fusion technology has been used for more than 15 years,
Bioverativ and Sobi have optimized the technology and are the first
companies to utilize it in the treatment of haemophilia. ALPROLIX is
manufactured using a human cell line in an environment free of animal
and human additives.

ALPROLIX is approved and marketed by Bioverativ for the treatment of
hemophilia B in the United States, Japan and Canada. It is also approved
in Australia, New Zealand, Brazil and other countries, and Bioverativ
has marketing rights in these regions. It is also authorised in the
European Union, Iceland, Liechtenstein, Norway and Switzerland, where it
is marketed by Sobi.

Allergic-type hypersensitivity reactions and development of inhibitors
have been observed with ALPROLIX in the treatment of hemophilia B,
including in previously untreated patients. For more information, please
see the full U.S.
prescribing information for ALPROLIX. Note that the indication for
previously untreated patients is not included in the EU
Product Information.

About Hemophilia B
Hemophilia B is caused by having
substantially reduced or no factor IX activity, which is needed for
normal blood clotting.¹ The World Federation of Hemophilia
estimates that approximately 28,000 people are currently diagnosed with
hemophilia B worldwide.²

People with hemophilia B may experience bleeding episodes in joints and
muscles that cause pain, decreased mobility and irreversible joint
damage. In the worst cases, these bleeding episodes can cause organ
bleeds and life-threatening hemorrhages. Infusions of factor IX
temporarily replace clotting factors necessary to resolve bleeding and,
when used prophylactically, to prevent new bleeding episodes.¹

About the Bioverativ and Sobi Collaboration
Bioverativ and
Sobi collaborate on the development and commercialization of ALPROLIX
and ELOCTATE® [Antihemophilic Factor (Recombinant), Fc Fusion Protein],
which is marketed as Elocta® in Europe. Bioverativ has final development
and commercialization rights in North America and all other regions in
the world excluding the Sobi territory, and has manufacturing
responsibility for ELOCTATE and ALPROLIX. Sobi has final development and
commercialization rights in the Sobi territory (essentially Europe,
North Africa, Russia and most Middle Eastern markets).

About Bioverativ
Bioverativ (NASDAQ: BIVV) is a global
biotechnology company dedicated to transforming the lives of people with
hemophilia and other rare blood disorders through world-class research,
development and commercialization of innovative therapies. Launched in
2017 following separation from Biogen Inc., Bioverativ builds upon a
strong heritage of scientific innovation and is committed to actively
working with the blood disorders community. The company’s mission is to
create progress for patients where they need it most and its hemophilia
therapies when launched represented the first major advancements in
hemophilia treatment in more than two decades. For more information,
visit www.bioverativ.com
or follow @bioverativ
on Twitter.

Bioverativ was created as a spin-off from Biogen’s hemophilia business
and separated from Biogen effective February 1, 2017. Bioverativ is an
independent, publicly-traded company, headquartered in Waltham,
Massachusetts. During a temporary transition period, which includes time
to allow Bioverativ to establish certain licenses and consents related
to ELOCTATE and ALPROLIX, each of Bioverativ and Biogen will have a
relationship to the products.

About Sobi™
Sobi is an international specialty healthcare
company dedicated to rare diseases. Sobi’s mission is to develop and
deliver innovative therapies and services to improve the lives of
patients. The product portfolio is primarily focused on Haemophilia,
Inflammation and Genetic diseases. Sobi also markets a portfolio of
specialty and rare disease products across Europe, the Middle East,
North Africa and Russia for partner companies. Sobi is a pioneer in
biotechnology with world-class capabilities in protein biochemistry and
biologics manufacturing. In 2015, Sobi had total revenues of SEK 3.2
billion (USD 385 M) and about 700 employees. The share (STO:SOBI) is
listed on Nasdaq Stockholm. More information is available at www.sobi.com.

Bioverativ Safe Harbor
This press release contains
forward-looking statements, including statements about the potential
benefits, safety profile, and efficacy of ALPROLIX in hemophilia B and
the potential of the Fc Fusion technology. These forward-looking
statements may be accompanied by such words as “anticipate,” “believe,”
“could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “plan,”
“potential,” “project,” “target,” “will” and other words and terms of
similar meaning. You should not place undue reliance on these
statements. These statements involve risks and uncertainties that could
cause Bioverativ’s actual results to differ materially from those
reflected in such statements, including, without limitation, risks
related to development of early stage programs, unexpected concerns that
may arise from additional data or analysis, regulatory authorities may
require additional information or further studies, regulatory
authorities may fail to expand product labeling, and other risks and
uncertainties associated with Bioverativ’s drug development and
commercialization activities described in the Risk Factors section of
Bioverativ’s filings with the Securities and Exchange Commission. These
statements are based on Bioverativ’s current beliefs and expectations
and speak only as of the date of this press release. Bioverativ does not
undertake any obligation to publicly update any forward-looking
statements.

References

¹ World Federation of Hemophilia. About Bleeding Disorders –
Frequently Asked Questions. Available at: http://www.wfh.org/en/page.aspx?pid=637#Difference_A_B.
Accessed on: January, 13, 2017.
² World Federation of
Hemophilia. Report on the Annual Global Survey 2013. Available at: http://www1.wfh.org/publications/files/pdf-1591.pdf.
Accessed on: January 13, 2017.

Contacts

BIOVERATIV
Media Contact:
Tracy Vineis, +1
781-663-4350
media@bioverativ.com
or
Investor
Relations Contact:
Susan Altschuller, +1 781-663-4360
IR@bioverativ.com
or
SOBI
Media
Contact:
Linda Holmström, + 46 708 73 40 95
linda.holmstrom@sobi.com
or
Investor
Relations Contact:
Jörgen Winroth, +1 347-224-0819
jorgen.winroth@sobi.com