March 29, 2012
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer

Clinical Trial Notification Accepted for SymBio’s Japan Phase 1 Trialof Rigosertib (SyB L-1101) in Refractory/Relapsed MDSTOKYO, Japan, March 29, 2012 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo, President &CEO: Fuminori Yoshida, “SymBio”) announced that clinical trial notification (CTN) has been accepted for
its Phase 1 clinical trial using rigosertib (SyB L-1101) in refractory and relapsed myelodysplastic
syndrome (MDS) patients.

Onconova Therapeutics, Inc., a U.S.-based biopharmaceutical company which has licensed rigosertib toSymBio, is conducting late-stage clinical trials with rigosertib (ON 01910.Na) in the U.S., Europe andIndia in hematological cancers and solid tumors.

A pivotal Phase III trial in refractory/relapsed MDS

patients was initiated under a Special Protocol Assessment from the U.S. FDA and is underway at morethan 50 centers in the U.S. and Europe.

The U.S. FDA has granted orphan drug designation for the useof rigosertib in MDS and pancreatic cancer.

In addition to the intravenous product in advanced-stage

development and with the successful completion of two Phase I trials, an oral formulation of rigosertib isbeing developed for frontline MDS in Phase II trials and other indications.

To date, more than 500

cancer patients have been treated with rigosertib in Phase I, II and III clinical trials conducted in the U.S.,
EU and India.

As well as this first trial for the treatment of refractory and relapsed MDS patients, SymBio is planning toinitiate a Phase I clinical trial for the treatment of frontline MDS using the oral form of rigosertib (SyBC-1101) based on promising results generated in U.S. Phase II clinical trials.

Patients with MDS often require frequent blood transfusions due to the development of severe anemia(decrease in number of red blood cells), with approximately one third of patients progressing to acute
myelogenous leukemia (AML). MDS remains an underserved therapeutic area with few available
treatment options for patients, hence SymBio is moving rigosertib through clinical development as
nimbly as possible.

[Please read the following for additional information on MDS, Rigosertib, and Onconova ][Contact]
Hiroki Maekawa
Board Director, Corporate Officer, Chief Financial Officer
Tel: +081(0)3 5472 1125

Note to Editors

About Myelodysplastic Syndromes (MDS)MDS represent a group of diverse myeloid (bone marrow) stem cell disorders with a poor prognosis that
gradually affect the ability of bone marrow to produce normal red blood cells, white blood cells, andplatelets.

Blood stem cells fail to mature into healthy blood cells, and the immature blood cells, calledblasts, do not function normally and either die in the bone marrow or enter the blood.

A higher percentof blasts is linked to a higher likelihood of developing leukemia and a poorer prognosis. The risk ofMDS increases with age with treatment being more difficult in the elderly population.

About Rigosertib Sodium
Rigosertib sodium is a small molecule inhibitor of critical pathways important in the growth and survivalof cancer cells.

Extensive Phase I and Phase II studies with rigosertib have been conducted at leading

institutions in the U.S. and abroad in more than 500 patients with solid tumors and hematologicalcancers, including MDS and AML. MDS and AML are blood disorders widely recognized as being
difficult to manage with limited therapeutic options available for patients, especially those withdrug-resistant disease. Onconova’s multi-site Phase III ONTIME trial in MDS patients is under aSpecial Protocol Assessment (SPA) from the U.S. FDA and is being supported by an award from theTherapeutics Acceleration Program (TAP) of the Leukemia and Lymphoma Society (LLS).
has granted Orphan Drug Designation for the use of rigosertib in MDS.

The FDA

The clinical program in solidtumors is also advancing with initiation of the Phase II/III combination ONTRAC trial (ON 01910.Na TRialin Patients with Advanced Pancreatic Cancer) and Phase II single agent trial in ovarian cancer.

Apatent for ON 01910.Na has been issued in the U.S. with international patent coverage.
®

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 DNArepair.

These candidates are derived from proprietary new chemical entities and non-ATP competitive

chemotypes.

In addition to rigosertib sodium (ON 01910.Na), Onconova is developing two otherproducts in clinical trials: ON 01210.Na (Ex-RAD®), an injectable and oral radioprotectant, andON 013105 for refractory lymphomas.

The oncology preclinical pipeline at Onconova includes

inhibitors of Plk2, ALK, CDK, JAK, and Bcr-Abl pathways and a novel immunoconjugate platform forarming therapeutic antibodies.

For additional information, please visit Onconova’s homepage at

http://www.onconova.com.

About SymBio Pharmaceuticals LimitedSymBio 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

it aspires to be a leading specialty pharma in Asia Pacific dedicated to addressing underserved medical

needs in oncology, hematology and autoimmune diseases.

The company’s lead drug candidate,bendamustine hydrochloride, has been successfully developed and launched in Japan forrefractory/relapsed indolent non-Hodgkin’s lymphoma (NHL) and mantle cell lymphoma.

SymBio isalso actively developing bendamustine in frontline indolent NHL, refractory/relapsed aggressive NHL
and multiple myeloma in Japan.
Taiwan.

The product has been launched in Hong Kong, Singapore, Korea andFor additional information, please visit our homepage at http://www.symbiopharma.com.