Alexion and Affibody Announce Partnership to Co-Develop Anti-FcRn Affibody® Molecule

Alexion
Pharmaceuticals, Inc. (NASDAQ:ALXN) and Affibody AB today announced
a partnership to co-develop ABY-039 for rare Immunoglobulin G
(IgG)-mediated autoimmune diseases. Currently in Phase 1 development,
ABY-039 is a bivalent antibody-mimetic that targets the neonatal Fc
receptor (FcRn). ABY-039 has been specifically designed to combine
Affibody’s protein therapeutics platform (Affibody^®
molecules) and Albumod™ technology to achieve a long half-life, which,
along with its small size provides the potential for less frequent,
convenient, at-home subcutaneous administration.

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“We believe there is significant opportunity to transform patient care
with FcRn-targeted therapies and are thrilled to add a second
clinical-stage anti-FcRn medicine to our pipeline with this
collaboration,” said John Orloff, M.D., Executive Vice President and
Head of Research & Development at Alexion. “While clinical development
is still early, we are excited by ABY-039’s potential to be an optimal
subcutaneous therapy across a number of IgG-mediated diseases, providing
patients with the possibility of a convenient self-administered
treatment option.”

“ABY-039 offers an innovative and novel approach to treating
IgG-mediated diseases. Its rapid onset, sustained response, long
half-life and potential for low volume administration hold great promise
as a self-administered subcutaneous anti-FcRn therapy of choice,” said
David Bejker, Chief Executive Officer of Affibody. “We look forward to
building our partnership with Alexion and leveraging their significant
development and commercial experience to accelerate the development of
ABY-039. This collaboration is another key step in the evolution of our
company that is aligned with our key strategic objectives.”

ABY-039 is being evaluated in a Phase 1 study in healthy volunteers.
This adaptive, double-blind, placebo-controlled study is evaluating the
safety, tolerability, pharmacokinetics and pharmacodynamics of ABY-039
and will aid in dose selection for future studies. The companies are
assessing potential indications for future development.

Under the terms of the agreement, Alexion will provide Affibody with an
upfront payment of $25 million, with the potential for additional
development- and sales-based milestones of up to $625 million and tiered
low double-digit royalty payments. Alexion will lead joint clinical
development of ABY-039 and commercialization activities. Affibody has
the option to co-promote ABY-039 in the U.S. and will lead clinical
development for an undisclosed indication.

The companies expect to close the transaction in the second quarter of
2019, subject to clearance under the Hart-Scott Rodino Antitrust
Improvements Act.

Alexion will discuss the partnership further during today’s Investor Day
event and webcast.

About FcRn
Antibodies play an important role in a healthy
body’s defense by fighting infections from bacteria and other invaders.
In autoimmune diseases, however, the body mistakenly attacks itself
through the production of pathogenic (disease-causing) antibodies of the
Immunoglobulin G (IgG) subtype. Neonatal Fc receptor (FcRn) rescues IgGs
from lysosomal degradation by binding them to endosomes and returning
them to the bloodstream. This helps prolong the half-life of IgG. In
healthy individuals, this function contributes to a normal immune
response. In many autoimmune conditions, however, FcRn prevents
lysosomal degradation of pathogenic IgGs associated with driving the
disease. Therefore, blocking the FcRn-IgG interaction has the potential
to drive degradation of IgG within cells and rapidly reduce circulating
pathogenic IgG.

About ABY-039
ABY-039 is a novel anti-FcRn
antibody-mimetic, which has been specifically designed to utilize the
advantages of Affibody’s technology platform to differentiate from
competing antibody and Fc-based approaches. ABY-039 is a small protein
ligand (~19 kDa, approximately an eighth of the size of an antibody) and
has an in vivo half-life exceeding that of antibody-based approaches.

About Affibody’s Technology Platform
Affibody^®
molecules are a class of small optimized proteins with high affinity
based on a non-immunoglobulin three-helix bundle domain scaffold.
Affibody^® molecules have certain potentially advantageous
features for therapeutic applications including (i) small size resulting
in rapid tissue penetration and efficient delivery of higher molar doses
for the same mass vs. larger proteins, and (ii) robustness resulting in
potential for alternative administration routes. The Albumod™ Platform
uses a small optimized protein with an albumin binding domain (5 kDa)
with high affinity to albumin (sub pM) to provide half-life extension
and a wider distribution profile than antibodies to Affibody^®
molecules and other therapeutic proteins. The Affibody^®
technology, which includes the Affibody^® molecules (6 kDa
size, no Fc function) and Albumod™ platform, enables modified and
enhanced pharmacokinetics through the albumin binding domain, offering
the same distribution profile as albumin.

About Alexion
Alexion is a global biopharmaceutical company
focused on serving patients and families affected by rare diseases
through the discovery, development and commercialization of
life-changing therapies. As the global leader in complement biology and
inhibition for more than 20 years, Alexion has developed and
commercializes two approved complement inhibitors to treat patients with
paroxysmal nocturnal hemoglobinuria (PNH) as well as the first and only
approved complement inhibitor to treat atypical hemolytic uremic
syndrome (aHUS) and anti-acetylcholine receptor (AchR) antibody-positive
generalized myasthenia gravis (gMG), and is also developing it for
patients with neuromyelitis optica spectrum disorder (NMOSD). Alexion
also has two highly innovative enzyme replacement therapies for patients
with life-threatening and ultra-rare metabolic disorders,
hypophosphatasia (HPP) and lysosomal acid lipase deficiency (LAL-D). In
addition, the company is developing several mid-to-late-stage therapies,
including a second complement inhibitor, a copper-binding agent for
Wilson disease and an anti-neonatal Fc receptor (FcRn) antibody for rare
Immunoglobulin G (IgG)-mediated diseases as well as several early-stage
therapies, including one for light chain (AL) amyloidosis and a second
anti-FcRn therapy. Alexion focuses its research efforts on novel
molecules and targets in the complement cascade and its development
efforts on the core therapeutic areas of hematology, nephrology,
neurology, and metabolic disorders. Alexion has been named to the Forbes
list of the World’s Most Innovative Companies seven years in a row and
is headquartered in Boston, Massachusetts’ Innovation District. The
company also has offices around the globe and serves patients in more
than 50 countries. This press release and further information about
Alexion can be found at: www.alexion.com.

[ALXN-G]

About Affibody
Affibody is a private clinical-stage Swedish
biotech company focused on developing into an integrated biopharma
company utilizing next generation biotherapeutics based on its unique
proprietary technology platforms: Affibody^® molecules and
Albumod™. The company operates a focused experimental medicine model and
currently has three clinical-stage programs. The first two are
therapeutic programs that target psoriasis and rare Immunoglobulin G
(IgG)-mediated autoimmune diseases. The third program is a diagnostic
imaging program that is directed primarily towards metastatic breast
cancer. In addition to its portfolio of innovative drug projects, the
company offers the half-life extension technology, Albumod™, for
outlicensing. For more information on Affibody, please visit the
company’s website at www.affibody.com.

Affibody AB is a holding of Patricia Industries, a subsidiary of
investment holding company Investor AB. Investor AB, a Swedish
investment company founded in 1916 by the Wallenberg family, is the
leading owner of high quality Nordic-based international companies. The
company makes controlled investments in leading companies with strong
market positions, brands and corporate cultures within industries
positioned for secular growth with the ambition to be the sole owner of
their companies, together with strong management teams and boards.

Forward-Looking Statement
This press release includes
forward-looking statements, including statements related to the
therapeutic and commercial potential of ABY-039, the research and
development plans for ABY-039, the potential of ABY-039 and other
anti-FcRn-targeted therapies and the potential benefits of the
collaboration. Such forward-looking statements are subject to risks and
uncertainties that could cause actual results to differ materially from
those expressed or implied in such statements. The process by which an
early stage product such as ABY-039 could potentially lead to an
approved product is long and subject to highly significant risks,
including for example, decisions of regulatory authorities regarding the
adequacy of our research, marketing approval or material limitations on
the marketing of our products, delays, interruptions or failures in
manufacture and supply, failure to satisfactorily address matters raised
by the U.S. Food and Drug Administration and other regulatory agencies,
the possibility that results of clinical trials are not predictive of
safety and efficacy results in broader patient populations, the
possibility that clinical trials could be delayed, the risk that
anticipated regulatory filings are delayed, and a variety of other risks
set forth from time to time in Alexion's filings with the SEC, including
but not limited to the risks discussed in Alexion's Annual Report on
Form 10-K for the fiscal year ended December 31, 2018 and in Alexion’s
other filings with the SEC. Alexion and Affibody AB disclaim any
obligation to update any of these forward-looking statements to reflect
events or circumstances after the date hereof, except when a duty arises
under law.

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