August 5, 2020
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer(Securities Code: 4582)

SymBio Announces Global Developmentof Anti-viral Drug Brincidofovir IVfor Treatment of Adenovirus Infection
after Hematopoietic Stem Cell Transplantation
TOKYO, Japan, August 5, 2020 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo, "SymBio")
today announced that the Company’s Board of Directors today approved a global clinical development
plan for antiviral drug brincidofovir (BCV) intravenous formulation.
SymBio will prioritize global development of BCV IV targeting adenovirus (AdV) infection occurring
after hematopoietic stem cell transplantation, an area with high unmet medical need as there
currently exists no effective treatment. Development will primarily be focused in Japan, the U.S., andthe EU. The Company will leverage the knowledge of BCV’s efficacy and safety gained through theclinical trials to potentially expand target indications to multi-viral infections occurring after
hematopoietic stem cell transplantation or viral infections after kidney or other organtransplantation, aiming to expand the market and maximize the business value of BCV.
Since acquiring the exclusive rights to BCV in September 2019, the Company has actively exchanged
ideas with experts in the area of infectious diseases, both in and outside Japan, in formulating theglobal development plan for BCV, including conducting an extensive examination of the scientific andmedical aspects of the plan and a business evaluation. Given the extensive antiviral effects of BCVagainst various dsDNA viruses*, we expect BCV IV to demonstrate efficacy in the treatment andprevention of various viral infections occurring after hematopoietic stem cell transplantation. TheCompany has determined to prioritize early development for AdV infectious disease after
hematopoietic stem cell transplantation which can be fatal without effective treatment and for which
there is currently no effective treatment and extremely high medical need worldwide. Based on thefindings of the clinical studies of BCV Oral conducted by SymBio’s US licensor of BCV, Chimerix Inc.
(head office: North Carolina, U.S.), SymBio anticipates that BCV IV will demonstrate efficacy andsafety against various infectious diseases such as AdV and cytomegalovirus (CMV).

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Statement from Mr. Fuminori Yoshida, President and Chief Executive Officer of SymBio: “Adenovirus
infections occurring after hematopoietic stem cell transplantation is an underserved therapeutic areawith urgent need for a new drug. Reflecting the views of the members of SymBio’s Global Advisory
Board into our strategic priorities and development plan, we will proceed with a global clinical study
for pediatric patients with adenovirus (AdV) infections occurring after hematopoietic stem celltransplantation, an area with extremely high unmet medical need, and gradually expand target
indications to other viral infectious diseases. Transformation into to a global business will be a newchallenge for SymBio.”
The Company does not expect the information presented herein to have any material impact on its
financial outlook for the fiscal year ending December 2020.

*dsDNA viruses
Double-stranded DNA (dsDNA) viruses includes herpesviridae, adenoviridae, polyomaviridae,
papillomaviridae, poxviridae families of viruses, such as CMV, AdV, HHV-6, BK virus, HSV1/2, VZV,HPV, JCV, and small pox virus.

About Brincidofovir
Brincidofovir (BCV) has a structure in which cidofovir (an antiviral drug already approved andmarketed in the U.S. and Europe, but unapproved in Japan; “CDV”) is bound to a lipid chain(hexadecyloxypropyl; “HDP”). It is quickly absorbed into the lipid bilayer membrane and efficiently
transfers into cells, and then the bound lipid chain is metabolized and separated from the structure
by intracellular phospholipases. This process generates an activator (CDV-PP; CDV diphosphate) thatis retained in the cells for a long period of time, dramatically raising the compound’s antiviral
activity. Furthermore, BCV avoids nephrotoxicity, a fundamental issue plaguing CDV, since HDP
conjugation prevents the accumulation of the compound in renal tubular epithelial cells throughorganic anion transporter 1 (OAT1) and CDV is released at low levels in the bloodstream.
SymBio entered into an exclusive global license agreement with Chimerix Inc. (Headquarters:Durham, NC, "Chimerix") for brincidofovir (BCV) on September 30, 2019. 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.
For further information, please see the SymBio’s press release dated October 1, 2019,https://www.symbiopharma.com/news/20191001.pdf

2About Chimerix
Chimerix is a development-stage biopharmaceutical company dedicated to accelerating theadvancement of innovative medicines that make a meaningful impact in the lives of patients livingwith cancer and other serious diseases. Its two clinical-stage development programs are dociparstat
sodium (DSTAT) and brincidofovir (BCV).
BCV is an antiviral drug candidate in development as a medical countermeasure for smallpox. For
further information, please visit the Chimerix website, www.chimerix.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 the Company incorporated its wholly-owned subsidiary in the U.S., called
SymBio Pharma USA, Inc. (Headquarters: Menlo Park, California, President: Mr. Fuminori Yoshida).
The Company’s underlying corporate mission is to “deliver hope to patients in need” as it aspires to bea leading global specialty biopharmaceutical company dedicated to addressing underserved medicalneeds.

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