October 1, 2019
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer(Securities Code: 4582)

SymBio Announces Exclusive Global License Agreementwith Chimerix for Antiviral Drug, Brincidofovir
With the development of anti-multiviral agent
SymBio transforms into a global business

TOKYO, Japan, September 30, 2019 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo,"SymBio") announces an exclusive global license agreement with Chimerix Inc. (Headquarters:Durham, NC, "Chimerix") for the antiviral drug, brincidofovir (BCV). Under the terms of theagreement, Chimerix grants SymBio exclusive worldwide rights to develop, manufacture, andcommercialize BCV in all human indications, excluding the prevention and treatment of smallpox.
With the exclusive worldwide license to BCV, SymBio will transition into a global business, establish
an integrated supply system for high-quality pharmaceuticals, and grow as a fully integrated
specialty pharma.
Based on BCV’s strong data, SymBio will initially target treatment of viral hemorrhagic cystitis(vHC)*1 and HHV-6 encephalitis (HHV-6)*2 after allogeneic hematopoietic stem cell transplantationand kidney transplantation to address critically underserved therapeutic areas. Although otherantiviral drugs are currently used for these diseases, there is a long-standing and significant medical
need for a treatment that is both effective and safe.
BCV is a lipid conjugate of cidofovir (CDV) *3, which is an antiviral drug already approved and marketedin the United States and the European Union, but unapproved in Japan. As BCV has not only higher
anti-viral activity, but also a superior safety profile in comparison with CDV, BCV is expected to be aneffective treatment against a wide spectrum of infectious diseases caused by DNA viruses, including
herpes viruses (including CMV), adenovirus, BK virus, papilloma virus, and smallpox virus. BCV’s
innovative mechanism of action*4, which is based on conjugating a lipid chain of specified length to a
CDV base, dramatically improves efficiency of uptake into the cells where BCV is converted into a
direct-acting agent in the cell, resulting in high anti-viral effect. Furthermore, BCV is easy to use due
to its low risk of nephrotoxicity, which is a serious side effect of CDV, making it a novel highly active
anti-multiviral drug.

1With the acquisition of the exclusive global rights to BCV, Symbio will execute its strategy to build aglobal presence. The Company will execute a rapid development and commercialization plan inJapan, and proceed with global development in major organ transplant markets, including the UnitedStates, Europe, and China. To make BCV available to patients in need as rapidly as possible, and at
the same time to maximize the value of BCV business, SymBio will explore partnerships taking into
consideration the regional market characteristics of the target diseases to make BCV available topatients worldwide.
Mr. Fuminori Yoshida, President and Chief Executive Officer of SymBio, stated, “Patients with viralhemorrhagic cystitis after hematopoietic stem cell transplantation, which is our initial development
target, have extremely poor prognosis and high fatality. Yet, the treatment area remains seriouslyunderserved requiring an effective therapy. There is also significant synergy generated with our corehematology business. We will position BCV as the foundation to build our global presence andtransition SymBio into a fully integrated global specialty pharma.”
Mr. Mike Sherman, President and Chief Executive Officer of Chimerix, stated, “SymBio’s success intransitioning to a commercial-stage biotechnology company, while simultaneously developing apipeline of novel molecules in oncology and virology, illustrates the strength of their capability andcapacity. SymBio is well positioned to explore worldwide development of brincidofovir beyondsmallpox and we are excited by the promise of this partnership.”Under the terms of the agreement, SymBio will pay Chimerix an upfront payment, royalties on net
sales of brincidofovir worldwide, and potential clinical, regulatory and commercial milestones. Any
material impact of the execution of this licensing agreement on Earnings Forecasts for the fiscal year
ending December 31, 2019 will be disclosed by the Company in a timely manner.

[Contact]
Investor Relations
Tel: +81 (0)3 5472 11252

(*1) Viral hemorrhagic cystitis
Adenovirus infection accompanied by hemorrhagic cystitis occurs often following hematopoietic stem
cell transplantation, and it is generally refractory and shows severe symptoms that afflict patientswith such as frequent urination, abdominal pain, and micturition pain. Advanced disease with
disseminated infection can be lethal. There are also reported cases where mortality occurs from renal
impairment associated with adenovirus infection. Transplantation with unrelated donors including
cord blood, of which there is a high proportion in Japan, is a potent risk factor for viral hemorrhagiccystitis. It is often extremely refractory due to the time required to reconstitute the immune system.
The only current therapies available to patients, including cidofovir (CDV), are unapproved or offlabel.

(*2) HHV-6 encephalitis
HHV-6 (Human herpesvirus 6) is the sixth human herpes virus. The reactivation of HHV-6 occurs in
30-70 % of allogeneic hematopoietic stem cell transplantation, and can cause HHV-6 encephalitis.
HHV-6 encephalitis typically develops within 2 to 6 weeks, and most frequently occurs in the 3rd week
after transplantation. Typically, symptoms gradually progress from memory impairment toconsciousness disorder and convulsions, which are the three major symptoms. The incidence ratio ofconvulsions has been reported to be 30% to 70%. In rapidly progressing cases, neurological symptoms
worsen with time, and many cases require respirator management for repeated convulsions andrespiratory depression. Early treatment is very important for patients with HHV-6 encephalitis, as
the patient's condition often worsens rapidly in a short time. According to clinical guidelines*, thefirst-line drug is foscarnet (FOS) or ganciclovir (GCV), and the second-line drug is cidofovir (CDV).
CDV is defined as the second-line drug due to its strong nephrotoxicity and poor delivery of the drug
into the cerebrospinal fluid (CSF). However, no studies have been conducted to confirm the clinicaleffects of these drugs that have been shown to be effective on HHV-6 infection in vitro.
* Guidelines for hematopoietic cell transplantation: Prevention and treatment of viral infections
HHV-6 (The Japan Society for Hematopoietic Cell Transplantation, February 2018 edition)(*3) Cidofovir (CDV)
Cidofovir was approved by the FDA in 1996 for the treatment of cytomegalovirus (CMV) retinitis in
AIDS patients. Cidofovir is a cytosine nucleotide derivative that inhibits replication of DNA viruses
such as adenovirus, papillomavirus, polyomavirus as well as herpesviruses. Cidofovir is also effective
against ganciclovir (GCV) resistance (UL97 gene mutation), and is considered useful in cases where
GCV resistance appears and foscarnet (FOS) cannot be used. Cidofovir has not been developed orapproved in Japan.

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(*4) Brincidofovir (BCV)Brincidofovir (BCV) is a lipid conjugate of cidofovir (CDV) with hexadecyloxypropyl (HDP), showing a
rapid incorporation to the plasma membrane with efficient cellular uptake due to the lipid conjugate.
Once uptaken inside target cells, the lipid chain is cleaved by action of intracellular phospholipases
releasing CDV, which is then converted to the active form, CDV diphosphate. As a result of CDV
diphosphate being retained in the cell for an extended period, the antiviral activity of BCV is
dramatically improved compared with CDV. Furthermore, BCV can greatly reduce the risk ofnephrotoxicity associated with CDV because HDP conjugation brings no accumulation of CDV inrenal tubular epithelial cell through the transporter (OAT-1) and low plasma exposure of CDV.

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About Chimerix
Chimerix (NASDAQ:CMRX) is a development-stage biopharmaceutical company dedicated toaccelerating the advancement of innovative medicines that make a meaningful impact in the lives ofpatients living with cancer and other serious diseases. Chimerix has developed two types ofnucleotide compounds using its own lipid technology. Chimerix was developing brincidofovir(CMX001) as the world's first drug with strong and broad activity against viral diseases (AdV, BKV,EBV, HHV-6, etc.) for which there is currently no effective treatment. In order to concentrate on
businesses centering on the oncology field, Chimerix Co., Ltd. out-licensed a global license excluding
smallpox to SymBio Pharmaceuticals in September 2019. In July 2019, “CX-01” was in-licensed fromCantex Pharmaceuticals, Inc., and Phase 3 is in development for acute myeloid leukemia (AML). For
more information on Chimerix, please visit its website (https://www.cimerix.com/).

About SymBio Pharmaceuticals Limited
SymBio Pharmaceuticals Limited was established in March, 2005 by Fuminori Yoshida who
previously served concurrently as Corporate VP of Amgen Inc. and founding President of Amgen
Japan. In May, 2016 SymBio incorporated its wholly-owned subsidiary in the U.S., called SymBio
Pharma USA, Inc. (Headquarters: Menlo Park, California, President: Mr. Fuminori Yoshida).
SymBio’s underlying corporate mission is to “deliver hope to patients in need” as it aspires to be aleading global specialty biopharmaceutical company dedicated to addressing underserved medical
needs with main therapeutic focus in oncology and hematology.
TREAKISYM® was approved for relapsed/refractory low-grade B-cell non-Hodgkin's lymphoma(“iNHL”) and mantle cell lymphoma in Japan in October, 2010, and was subsequently approved forchronic lymphocytic leukemia and first-line iNHL. Symbio Pharmaceuticals currently markets
TREAKISYM® in Japan, South Korea, and Singapore through Eisai Co., Ltd., and in Taiwan through
InnoPharmax Inc. SymBio recorded net sales of JPY 8.5 billion in Japan for 2018 on an NHI(National Health Insurance) drug price basis. Since July 2018, TREAKISYM has been designated as
the standard therapy for the three approved indications under the Guidelines for HematologicalMalignancies issued by the Japanese Society of Hematology.

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