One Amgen Center Drive
Thousand Oaks, CA 91320-1799
Telephone +1-805-447-1000
www.Amgen.com
Kyowa Kirin Corporate
Communications Dept.
1-9-2, Otemachi, Chiyoda-ku,
Tokyo, 100-0004, Japan
Telephone +81-3-5205-7205
www.kyowakirin.com

News Release
AMGEN AND KYOWA KIRIN TO JOINTLY DEVELOP AND
COMMERCIALIZE KHK4083, A PHASE 3-READY, POTENTIAL
FIRST-IN-CLASS TREATMENT FOR ATOPIC DERMATITISAgreement Renews Successful Global Collaboration That led to
Several Groundbreaking Therapies in Multiple Disease Areas
KHK4083 Depletes OX40-Expressing T cells Associated with Atopic
Dermatitis and Several Other Inflammatory Diseases
Moderate-to-Severe Atopic Dermatitis Affects Nearly 30 Million People
in Major Global Markets1
Amgen to Host Investor Call at 8:00 a.m. EST
THOUSAND OAKS, Calif. and TOKYO, Japan, (June 1, 2021) -- Amgen (NASDAQ: AMGN) andKyowa Kirin Co., Ltd. (TSE: 4151) today announced an agreement to jointly develop andcommercialize KHK4083, which is Kyowa Kirin’s potential first-in-class, Phase 3-ready anti-OX40
fully human monoclonal antibody in development for the treatment of atopic dermatitis, withpotential in other autoimmune diseases. In February, Kyowa Kirin announced positive results froma Phase 2 study of KHK4083 in patients with moderate-to-severe atopic dermatitis, which affects
nearly 30 million people in major global markets1.
Under terms of the agreement, Amgen will lead the development, manufacturing, andcommercialization for KHK4083 for all markets globally, except Japan, where Kyowa Kirin willretain all rights. Additionally, Kyowa Kirin will co-promote KHK4083 with Amgen in the U.S. andhave opt-in rights to co-promote KHK4083 in certain other markets outside the U.S., including inEurope and Asia. Amgen will make a $400 million up-front payment to Kyowa Kirin and future

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AMGEN AND KYOWA KIRIN TO JOINTLY DEVELOP AND COMMERCIALIZEKHK4083, A PHASE 3-READY, POTENTIAL FIRST-IN-CLASS TREATMENT FORATOPIC DERMATITISPage 2
contingent milestone payments potentially worth up to an additional $850 million, as well as
significant royalty payments on future global sales. Kyowa Kirin and Amgen will share global
development costs, except in Japan, and U.S. commercialization costs. Amgen will consolidate
sales for KHK4083 in all markets globally, except for Japan. Amgen also will leverage uniquedata from its deCODE Genetics subsidiary to inform the potential use of KHK4083 in indications
beyond atopic dermatitis. The closing of the transaction is conditioned on obtaining any
necessary consents and approvals.
“Kyowa Kirin has a long legacy of partnering with other companies to deliver the full value of ourscientific discoveries and novel medicines for patients,” says Masashi Miyamoto, Ph.D., president
and chief executive officer at Kyowa Kirin. “KHK4083 is an important asset in our global pipeline.
We know Amgen well, and this alliance will build on the past success and trust we have, bringing
additional resources and therapeutic expertise to KHK4083’s development and commercialization,
to meet the needs of patients living with atopic dermatitis who seek alternative treatment options.”
KHK4083 is an anti-OX40 fully human monoclonal antibody discovered by Kyowa Kirin andengineered with Kyowa Kirin’s patented POTELLIGENT® defucosylation technology to enhance
its antibody-dependent cellular cytotoxicity (ADCC) activity. KHK4083 has been shown toselectively deplete activated T cells that are critical in the development of atopic dermatitis.
Kyowa Kirin antibodies powered by POTELLIGENT technology with ADCC activity are currently
marketed in therapeutic areas including Oncology and Asthma. This potent antibodyenhancement platform is also licensed to numerous third parties throughout thebiopharmaceutical industry.
“Kyowa Kirin was one of Amgen’s very first collaborators and we are delighted to be joining forces
with them once again to advance this promising late-stage asset to treat atopic dermatitis,” said
Robert A. Bradway, chairman and chief executive officer at Amgen. “We will take advantage ofour two decades of experience in inflammatory disease, as well as our industry-leading human
genetics capabilities, to help realize the full potential of KHK4083 as quickly as possible.”Amgen is a global leader in treating inflammatory diseases, with a portfolio of marketed medicinesthat includes Otezla®, Enbrel®, AMGEVITA® (a biosimilar to Humira®), and AVSOLA® (abiosimilar to Remicade®). Amgen’s pipeline of investigational therapies includes tezepelumab(filed for U.S. FDA approval in May 2021 as a potential first-in-class treatment for severe asthma),
ABP 654 (a biosimilar to STELARA®), and several innovative molecules in Phase 2b
development for systemic lupus erythematosus and celiac disease.
“KHK4083 is another example of our world-leading expertise in antibody engineering, appliedtarget selection and optimization. We are proud to be a science-led organization whose researchcapabilities continue to produce meaningful discoveries, while also taking advantage of open
innovation, that offers potential for improving treatment paradigms,” said Yoshifumi Torii, Ph.D.,
executive officer, vice president, Head of Global R&D Division at Kyowa Kirin. “Results fromclinical trials for KHK4083, including Phase 2 data, show great promise and we look forward to
initiating a late-stage global program with Amgen to deepen our understanding of this asset.”In 1984, Amgen and Kirin Holdings Co., Ltd (former Kirin Brewery Co., Ltd), the parent company
of Kyowa Kirin, established a 50-50 joint venture to develop and commercialize EPOGEN®
(Japanese brand name: ESPO®), which, in 1989, became the first Amgen medicine approved in

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AMGEN AND KYOWA KIRIN TO JOINTLY DEVELOP AND COMMERCIALIZEKHK4083, A PHASE 3-READY, POTENTIAL FIRST-IN-CLASS TREATMENT FORATOPIC DERMATITISPage 3
the U.S., and, in 1990, became the first Kirin medicine approved in Japan. Over time, the joint
venture expanded to include the development and commercialization of several other medicines,
including NEUPOGEN® (GRAN® in Japan), Neulasta® (G-Lasta® in Japan), Aranesp® (NESP®
in Japan), and Nplate® (Romiplate® in Japan). In 2017, the companies announced that the joint
venture would become a wholly owned subsidiary of Amgen, with Kyowa Kirin in-licensing certain
Amgen medicines in the Asia-Pacific region.
Amgen Webcast Investor Call
Amgen will host a webcast call for the investment community on June 1, 2021, at 8:00 a.m.
EST. Peter H. Griffith, executive vice president and chief financial officer, David M. Reese, M.D.,
executive vice president of Research and Development, and Murdo Gordon, executive vicepresident of Global Commercial Operations at Amgen will participate.
Live audio of the conference call will be broadcast over the internet simultaneously and will beavailable to members of the news media, investors and the general public. The webcast, as withother selected presentations regarding developments in Amgen's business given at certain
investor and medical conferences, can be accessed on Amgen's website, www.amgen.com,
under Investors. Information regarding presentation times, webcast availability and webcast links
are noted on Amgen's Investor Relations Events Calendar. The webcast will be archived andavailable for replay for at least 90 days after the event.
About the KHK4083 Phase 2 Study
In February 2021, Kyowa Kirin reported that KHK4083 met the primary endpoint in a Phase 2
randomized, double-blind and placebo-controlled clinical study conducted in the U.S., Japan,
Canada, and Germany. The study included 274 patients with moderate-to-severe atopic
dermatitis, who were not adequately controlled with topical agents. All KHK4083 cohorts
achieved superiority to the placebo cohort for the primary endpoint of percent change frombaseline in Eczema Area and Severity Index (EASI) at 16 weeks with statistical significance. In
addition, there was significant difference in the percentage of patients achieving an EASI-75(EASI score of 75% or greater improvement from baseline) at 16 weeks and the percentage ofpatients achieving the Investigator's Global Assessment (IGA) of 0 or 1 with an improvement of 2
points or more at 16 weeks in all KHK4083 cohorts compared to the placebo cohort. Sustained
efficacy of KHK4083 was observed beyond week 16.
Common treatment-emergent adverse events for KHK4083 cohorts were pyrexia,
nasopharyngitis, worsening of atopic dermatitis and chills during the first 16 weeks. Pyrexia andchills events were mild to moderate in intensity, most of them were due to injection reaction andobserved only after the first administration of the investigational product. There were no events ofsevere hypersensitivity reactions and no deaths observed in the study.
About Atopic Dermatitis
Atopic dermatitis is a chronic disease in which the immune system becomes disordered andoveractive, triggering inflammation that damages the skin barrier. People with atopic dermatitis
can get rashes anywhere on the body that can ooze, weep fluid and bleed when scratched,making skin vulnerable to infection. Skin can become dry and discolored, and repeated scratching

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AMGEN AND KYOWA KIRIN TO JOINTLY DEVELOP AND COMMERCIALIZEKHK4083, A PHASE 3-READY, POTENTIAL FIRST-IN-CLASS TREATMENT FORATOPIC DERMATITISPage 4can cause thickening and hardening of the skin. Atopic dermatitis typically begins in childhood,affecting 15% to 20% of children and 1% to 3% of adults worldwide. The incidence of the disease
has increased two- to three-fold since the 1970s. People who have asthma and/or hay fever or
who have family members who do, are more likely to develop atopic dermatitis.
About OX40
OX40 is a co-stimulatory molecule that is one of the tumor necrosis factor receptor (TNFR) family
members. It plays an important role in maintaining T cell proliferation and survival and in theformation of memory T cells. OX40 is expressed on the surface of effector T cells (CD4 positive)
activated by antigens. It has been reported that effector T cells expressing OX40 are present in
the lesions of atopic dermatitis.
About Kyowa Kirin
Kyowa Kirin strives to create and deliver novel medicines with life-changing value. As a Japanbased Global Specialty Pharmaceutical Company with a more than 70-year heritage, thecompany applies cutting-edge science including an expertise in antibody research andengineering, to address the needs of patients and society across multiple therapeutic areas
including Nephrology, Oncology, Immunology/Allergy and Neurology. Across our four regions –Japan, Asia Pacific, North America and EMEA/International – we focus on our purpose, to makepeople smile, and are united by our shared values of commitment to life, teamwork/Wa, innovation,and integrity. You can learn more about the business of Kyowa Kirin at:https://www.kyowakirin.com.
About Amgen
Amgen is committed to unlocking the potential of biology for patients suffering from serious
illnesses by discovering, developing, manufacturing and delivering innovative human therapeutics.
This approach begins by using tools like advanced human genetics to unravel the complexities of
disease and understand the fundamentals of human biology.
Amgen focuses on areas of high unmet medical need and leverages its expertise to strive forsolutions that improve health outcomes and dramatically improve people's lives. A biotechnology
pioneer since 1980, Amgen has grown to be one of the world's leading independent biotechnology
companies, has reached millions of patients around the world and is developing a pipeline of
medicines with breakaway potential.
For more information, visit www.amgen.com and follow us on www.twitter.com/amgen.
Amgen Forward-Looking Statements
This news release contains forward-looking statements that are based on the current expectations
and beliefs of Amgen. All statements, other than statements of historical fact, are statements that
could be deemed forward-looking statements, including any statements on the outcome, benefits
and synergies of collaborations, or potential collaborations, with any other company (including
BeiGene, Ltd. or any collaboration to manufacture therapeutic antibodies against COVID-19), theperformance of Otezla® (apremilast) (including anticipated Otezla sales growth and the timing of
non-GAAP EPS accretion), the Five Prime Therapeutics, Inc. acquisition, or the collaboration with

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AMGEN AND KYOWA KIRIN TO JOINTLY DEVELOP AND COMMERCIALIZEKHK4083, A PHASE 3-READY, POTENTIAL FIRST-IN-CLASS TREATMENT FORATOPIC DERMATITISPage 5
Kyowa Kirin Co., Ltd. to jointly develop and commercialize KHK4083, as well as estimates ofrevenues, operating margins, capital expenditures, cash, other financial metrics, expected legal,
arbitration, political, regulatory or clinical results or practices, customer and prescriber patterns orpractices, reimbursement activities and outcomes, effects of pandemics or other widespread
health problems such as the ongoing COVID-19 pandemic on Amgen’s business, outcomes,
progress, or effects relating to studies of Otezla as a potential treatment for COVID-19, and othersuch estimates and results. Forward-looking statements involve significant risks and uncertainties,
including those discussed below and more fully described in the Securities and Exchange
Commission reports filed by Amgen, including its most recent annual report on Form 10-K andany subsequent periodic reports on Form 10-Q and current reports on Form 8-K. Unless otherwise
noted, Amgen is providing this information as of the date of this news release and does notundertake any obligation to update any forward-looking statements contained in this document
as a result of new information, future events or otherwise.
No forward-looking statement can be guaranteed and actual results may differ materially fromthose Amgen projects. Discovery or identification of new product candidates or development of
new indications for existing products cannot be guaranteed and movement from concept to
product is uncertain; consequently, there can be no guarantee that any particular productcandidate or development of a new indication for an existing product will be successful andbecome a commercial product. Further, preclinical results do not guarantee safe and effective
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problems with its products, including its devices, after they are on the market.
Amgen’s results may be affected by its ability to successfully market both new and existingproducts domestically and internationally, clinical and regulatory developments involving current
and future products, sales growth of recently launched products, competition from other products
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AMGEN AND KYOWA KIRIN TO JOINTLY DEVELOP AND COMMERCIALIZEKHK4083, A PHASE 3-READY, POTENTIAL FIRST-IN-CLASS TREATMENT FORATOPIC DERMATITISPage 6government, Amgen could become subject to significant sanctions. Further, while Amgenroutinely obtains patents for its products and technology, the protection offered by its patents andpatent applications may be challenged, invalidated or circumvented by its competitors, or Amgenmay fail to prevail in present and future intellectual property litigation. Amgen performs a
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References
1. Decision Resources Group, Atopic Dermatitis/Atopic Eczema Disease Landscape &Forecast, April 2021. © [2021] DR/Decision Resources, LLC. All rights reserved.
Reproduction, distribution, transmission or publication is prohibited. Reprinted withpermission. Major global markets are the U.S., France, Germany, Italy, Spain, the U.K.
and Japan.

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