March 26, 2013
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer

SymBio Initiates Japanese Phase I Trial of Oral rigosertib (SyB C-1101) in Frontline MDSTOKYO, Japan, March 26, 2013 -- SymBio Pharmaceuticals Limited (JASDAQ: 4582) announced today that itcommenced enrollment of its Phase I clinical trial for oral rigosertib (SyB C-1101) in frontline myelodysplastic
syndrome (MDS) patients in Japan.
Under the terms of the license agreement concluded with Onconova Therapeutics, Inc. in July, 2011, SymBio
has an exclusive license to develop and commercialize rigosertib in Japan and Korea. Rigosertib is a novel,patent protected inhibitor of PI3-kinase and PLK pathways in cancer cells.

MDS patients often require frequent blood transfusions due to the development of severe anemia (decreasein number of red blood cells), with a high rate of progression to acute myelogenous leukemia (AML). There
are an estimated 11,000 MDS patients in Japan alone. Currently there is no approved drug for patients who
have experienced drug failure after frontline treatment of MDS using hypomethylating agents, and there is anurgent need to develop new therapies for the treatment of both relapsed/refractory (r/r) and frontline MDS.

Onconova Therapeutics, Inc. is currently conducting late-stage clinical trials with rigosertib (ON 01910.Na) inthe U.S. and Europe for the treatment of hematologic malignancies and solid tumors. A pivotal trial in r/r MDS
is underway using the intravenous (IV) formulation of rigosertib (SyB L-1101). The U.S. FDA has grantedorphan drug designation for the use of rigosertib in MDS, and has agreed to a Special Protocol Assessment(SPA) for this Phase III trial.
A pair of Phase II trials are underway in the U.S. for development of the oral formulation of rigosertib asfrontline treatment for lower-risk MDS.

In addition to SymBio’s Phase I trial with oral rigosertib in frontline MDS, a Phase I trial in r/r MDS patientsusing the IV formulation of the drug is also underway in Japan. SymBio is developing rigosertib expeditiously,
shortening development time and making this innovative drug available to MDS patients in need.

[Please read the following for additional information on MDS, rigosertib, and Onconova ][Contact]
Tomoyuki Watanabe
Director, Head of Corporate Planning Division
Tel: +081(0)3 5472 1125

Note to Editors

About Myelodysplastic Syndrome (MDS)MDS represents a group of diverse myeloid (bone marrow) stem cell disorders that gradually affect the abilityof bone marrow to produce normal red blood cells, white blood cells, and platelets. Blood stem cells fail tomature into healthy blood cells, and the immature blood cells, called blasts, do not function normally andeither die in the bone marrow or enter the blood. A higher percent of blasts is linked to a higher likelihood ofdeveloping leukemia and poorer overall prognosis. The risk of MDS increases with age and the diseasecommonly affects the elderly.
About rigosertib
Rigosertib (ON 01910.Na) is a small molecule inhibitor that targets the PI3-kinase and PLK mitotic pathways,
critical pathways to the growth and survival of cancer cells. Phase I-III studies with rigosertib have been
conducted at leading institutions in more than 800 patients with solid tumors and hematological cancers,
including myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). ONTIME, a multi-site Phase III
trial in r/r MDS patients, is being conducted under a Special Protocol Assessment (SPA) from the U.S. Foodand Drug Administration (FDA) and is being supported by an award from the Therapeutics Acceleration
Program of The Leukemia and Lymphoma Society. Both the FDA and European Medicines Agency have
granted Orphan Drug Designation for the use of rigosertib in r/r MDS. The rigosertib clinical program in solidtumors is also advancing in ONTRAC, a Phase III adaptive design trial for pancreatic cancer. ONTRAC is aPhase III, multicenter, randomized, controlled study (with an interim analysis for futility) that compares theefficacy and safety of gemcitabine alone vs. rigosertib combined with gemcitabine in patients with previously
untreated metastatic pancreatic cancer. ONTARGET is a Phase II, randomized, two-arm study that will assess
the efficacy and safety of oral rigosertib in transfusion-dependent low or intermediate-1 MDS patients, basedon IPSS classification. Primary endpoints of the study are transfusion independence and erythroid response.

About Onconova Therapeutics, Inc.
Onconova Therapeutics, based in Newtown, PA and Pennington, NJ, discovers and develops novel small
molecule therapeutics directed against targets involved in signal transduction, cell-cycle, and DNA repair. Thecompany’s most advanced product, rigosertib (ON 01910.Na), is now in a pivotal trial being conducted under aSpecial Protocol Assessment (SPA) from the U.S. Food and Drug Administration (FDA) for r/r MDS as well as
in a Phase III trial for pancreatic cancer. In addition to rigosertib, Onconova is developing two other clinicalstage products: Ex-RAD® (recilisib, a radioprotectant) and ON 013105 (a novel anti-cancer agent initiallydirected toward refractory lymphoma, including mantle cell lymphoma). For additional information, please visit
http://www.onconova.com.

About SymBio Pharmaceuticals Limited
SymBio Pharmaceuticals Limited, based in Tokyo, Japan, was established in March, 2005, by Fuminori
Yoshida, who previously served concurrently as Corporate VP of Amgen Inc. and founding President ofAmgen Japan. The company’s underlying corporate mission is to “deliver hope to patients in need” as itaspires to be a leading specialty pharma in Asia Pacific dedicated to addressing underserved medical needs
with focus in the areas of oncology, hematology and autoimmune disease. The company’s lead drug,
bendamustine hydrochloride, has been successfully developed and launched in Japan for refractory/relapsed(r/r) low-grade non-Hodgkin’s lymphoma (LG-NHL) and mantle cell lymphoma. SymBio is also actively
developing bendamustine in frontline LG-NHL, r/r aggressive NHL and multiple myeloma in Japan. The drug
has also been launched in Hong Kong, Singapore, Korea and Taiwan. For additional information, please visit
our homepage at http://www.symbiopharma.com.