December 4, 2018
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer(Securities Code: 4582)

Onconova Presents Results from Phase 2 Trial of Oral Rigosertib in Myelodysplastic
Syndromes (MDS) at the ASH 2018 Meeting
TOKYO, Japan, December 4, 2018 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo,"SymBio") today announced that its U.S. licensor for rigosertib, Onconova Therapeutics, Inc.,(Headquarters: Newtown, PA, “Onconova”) announced the presentation of the efficacy and safety
results of oral rigosertib in combination with azacitidine (Vidaza®) in patients with HR-MDS reported
at an oral presentation during the 60th American Society of Hematology (ASH) Annual Meeting &Exposition in San Diego, California on December 1st, 2018.
Oral Presentation: Phase 2 Expansion Study of Oral Rigosertib Combined with Azacitidine treatment

in Patients with Higher-Risk (HR) Myelodysplastic Syndromes (MDS): Efficacy and Safety Results in
HMA Treatment Naïve & Relapsed (Rel)/Refractory (Ref) Patients
Summary of the oral presentation:“Patients received either 840 mg or 1,120 mg of oral rigosertib daily divided into two doses, incombination with a standard dose of injectable azacitidine. The overall response rate (ORR) in 29
HMA naïve patients, was 90%; including 10 patients (34%) with Complete Remission (CR). Among the26 evaluable HMA-failed patients, the ORR was 54% including 8% CR or partial remission. Other thangenitourinary adverse events, the adverse event profile was similar to those described for azacitidine
alone in this patient population. A Safety Optimization Strategy was implemented for the higher dose
cohort of 1,120 mg of oral rigosertib, resulting in mitigation of the target genitourinary adverse events.
In conclusion, oral rigosertib in combination with azacitidine was well tolerated in HMA naïve andHMA failed HR-MDS patients. The combination produced an encouraging rate of overall response andcomplete remission in both groups. Based on the results of this study, a pivotal Phase 3 trial in HMAnaïve HR-MDS patients is planned.”
For more information, please see Onconova’s website:
https://investor.onconova.com/press-releases
Statement from Fuminori Yoshida, President and CEO of SymBio: “Based on the favorable trial resultspresented at the American Society of Hematology, SymBio plans to participate with respect to Japan in
an Onconova intiated international Phase 3 clinical trial for oral rigosertib in combination withazacytidine in HMA naïve HR-MDS patients.”1

About myelodysplastic syndromes (MDS)MDS patients often require frequent blood transfusions due to the development of severe anemia(decrease in the number of red blood cells), with a high rate of progression to acute myelogenous
leukemia (AML). The number of MDS cases are expected to increase as the population ages. MDS andAML are widely recognized as two blood disorders that are difficult to manage given the limited
therapeutic options available for patients, particularly for patients who have a drug-resistant form ofthe disease. A high unmet medical need clearly exists for the establishment of new effective therapies
to treat both lower-risk and higher-risk MDS. The number of drug-treated MDS patients is estimatedto be about 7,700 in Japan (CancerMPact 2016).
About Rigosertib
Rigosertib is a small molecule inhibitor that has a new mechanism of action: it inhibits the activationof Ras as an oncogene-related product, thereby blocking the action of multikinases, including PI3K,and inhibits cellular signaling in cancer cells necessary for their survival and proliferation, thus
killing cancer cells.
SymBio obtained the development and commercialization licensing rights for Rigosertib from
Onconova in July, 2011 for Japan and Korea.
About Onconova Therapeutics, Inc.
Onconova Therapeutics, Inc. is a clinical-stage biopharmaceutical company focused on discovering anddeveloping novel products to treat cancer. Onconova's clinical and pre-clinical stage drug developmentcandidates are derived from its extensive chemical library and are designed to work against specificcellular pathways that are important in cancer cells, while causing minimal damage to normal cells. Inaddition to Rigosertib, Onconova's most advanced drug candidate under development, two other drugcandidates are in clinical trials and several other compounds are in the pre-clinical stage ofdevelopment. For more information, please visit http://www.onconova.com.
About SymBio Pharmaceuticals Limited
SymBio Pharmaceuticals Limited was established in March, 2005 by Fuminori Yoshida whopreviously 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 medical
needs with main therapeutic focus in oncology, hematology and pain management.

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