February 13, 2024
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer(Securities Code: 4582)

Preliminary Results of Phase 2a Clinical Trial of Intravenous Brincidofovir (IV BCV) in
Immunocompromised Patients with Adenovirus Infection Selected for Oral Presentation
at 50th Annual Meeting of the EBMT in Glasgow
TOKYO, Japan, February 13, 2024 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo,"SymBio" or the “Company”) is conducting a Phase 2a clinical trial (NCT04706923) of intravenousbrincidofovir ("IV BCV") in immunocompromised patients, including patients who have hadhematopoietic stem cell transplantation, with adenovirus (“AdV”) viremia or disseminated AdV
disease (the “Study”). SymBio today announced that an abstract of the preliminary results of theStudy showing the antiviral activity of IV BCV against AdV infection has been selected for an oral
session at 50th Annual Meeting of the EBMT, which will be held April 14-17, 2024, in Glasgow,
Scotland, UK.
The presenter is Michael Grimley, MD, Medical Director, Division of Bone Marrow Transplantation
and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio. Thepresentation will be the third oral presentation and the first presentation in Europe of POC data
showing the antiviral activity of IV BCV against AdV infection, as confirmed by the clearance of AdVfrom blood. The presentation follows oral presentations given at the 65th Annual Meeting of theAmerican Society of Hematology held in December 2023, which received a great many positive
responses, and at the 2024 Tandem Meetings of ASTCT and CIBMTR in February 2024. AdV may
cause life threatening or fatal infections in immunocompromised patients. There is no approved
effective treatment, and it is an underserved therapeutic area with highly unmet medical needs. For
more information on this presentation, please see information at the link below.

[Contact]
Investor Relations
Tel: +81 (0)3 5472 1125
Presentation Details:
https://ebmt2024.abstractserver.com/program/#/details/presentations/804
Title: “PRELIMINARY RESULTS OF PHASE 2A CLINICAL TRIAL TO EVALUATE SAFETY, TOLERABILITY AND
ANTIVIRAL ACTIVITY OF INTRAVENOUS BRINCIDOFOVIR IN IMMUNOCOMPROMISED PATIENTS WITH1ADENOVIRUS INFECTION”
Location: Hall 3 South
Time: Monday, April 15, 11:00 – 12:15
Session: OS03 Oral Session 3 | Infection - diagnosis, management and outcome
Presentation Time: 11:09 – 11:18(Note)
About the anti-viral drug Brincidofovir
Brincidofovir (BCV) has a new mechanism of action as a lipid conjugate of cidofovir (CDV). CDV is anantiviral drug already approved and marketed in the United States and the European Union, but
unapproved in Japan. BCV is expected to be an effective treatment against a wide spectrum of dsDNA
virus infections (cytomegalovirus, adenovirus, Epstein-Barr virus, herpes virus, BK virus,
papillomavirus and smallpox virus including monkeypox, etc.), with superior features such as highactivity antiviral effect in comparison with CDV and other antiviral drugs. Due to the breakthroughnature of the BCV molecule, in which a specific length of lipid chain is attached to the CDV, BCV isconverted into a molecule that acts directly within the cell, thereby dramatically increasing theefficiency of cellular uptake and showing a high antiviral activity.
In September 2019, SymBio entered into a license agreement with Chimerix for the exclusive worldwide
rights to develop, market, and manufacture BCV for all diseases except orthopoxviruses (such assmallpox and monkeypox). The tablets and oral suspension (oral formulation) were approved on June4, 2021, for the treatment of smallpox in adults and pediatric patients, including neonates.
In addition to its high antiviral activity, BCV is also expected to have anti-tumor effects. We arecurrently conducting collaborative studies with the National Cancer Centre Singapore, the Universityof California, San Francisco, and other institutions to confirm its anti-cancer activity and to identify
synergistic effects when combined with its antiviral activity.
Clinical trials and important R&D collaborations with prominent research institutions include:- Initiated a Phase II clinical trial in patients with adenovirus infection after hematopoietic stem celltransplantation (March 2021) and received Fast Track designation from the FDA (April 2021). Proof ofConcept (POC) of antiviral efficacy established based on data up to cohort 3 (May 2023).
- Initiated a non-clinical trial at the University of California, San Francisco Neurosurgery Brain Tumor
Center to evaluate the anti-tumor effect of BCV on refractory brain tumors (September 2021).
- In recent years, numerous studies have demonstrated that EBV is a risk factor for MS. SymBio
entered into CRADA with the NINDS in March 2023 to establish a new antiviral treatment method forMS, and has been conducting collaborative research to develop a clinical trial.
- CRADA with the National Institute of Allergy and Infectious Diseases (NIAID), affiliated with the2

NIH, to evaluate the efficacy of BCV for EB virus-associated lymphoproliferative diseases (April 2023).
- Research on the involvement of infection by reactivation of latent viruses in various neurologicalseverity diseases of the brain, including Alzheimer's disease, has been ongoing for the past several years,
and a simple three-dimensional mimicry of human neural stem cell cultures and brain tissue
established by Tufts University in the United States, the A Sponsored Research Agreement was signed(December 2022) to examine the effect of BCV on HSV infection using a herpes simplex virus (HSV)
infection/reactivation model established by Tufts University in the U.S., which uses human neural stem
cells cultured to mimic brain tissue in three dimensions.
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: Durham, North Carolina, representative: Stephane Berthier). The Company’s
underlying corporate mission is to “deliver hope to patients in need” as it aspires to be a leading global
specialty biopharmaceutical company dedicated to addressing underserved medical needs.

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