December 13, 2011
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer

Onconova Presents Phase I Data for Oral Rigosertib
at the 53rd American Society of Hematology Annual Meeting- Oral Rigosertib (ON 01910.Na) Advancing to Phase II -TOKYO, Japan, December 13, 2011 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo,“SymBio”) announces that Onconova Therapeutics®, Inc. (Headquarters: Newtown, PA and Pennington,
NJ, “Onconova”) presented positive data from its US Phase I trial in myelodysplastic syndrome (MDS)
patients treated with oral rigosertib (ON 01910.Na) at the 53rd American Society of Hematology (ASH)
Annual Meeting and Exposition in San Diego, CA on December 12, 2011. SymBio signed a license
agreement with Onconova in July, 2011, for the exclusive right to develop and commercialize both theintravenous and oral forms of rigosertib in Japan and Korea.

An oral dosage form of rigosertib has completed a Phase I dose escalation trial with 33 MDS patients inthe U.S. The rigosertib capsule formulation was well tolerated and pharmacodynamically relevant
doses were achieved in MDS patients with encouraging signs of clinical activity observed, including twocases of bone marrow responses in higher-risk patients refractory to hypomethylating agents, reduced
need for red cell transfusions in low-risk, transfusion-dependent patients, and transition to transfusion
independence in some patients. Based on these results, Phase II studies will be conducted using oral
rigosertib in Low or Intermediate-1 risk, transfusion-dependent MDS patients.

Onconova is conducting late-stage clinical trials with rigosertib, a patent protected multi-kinase inhibitorwith a unique mode of action, in the U.S., Europe and India for the treatment of MDS and solid tumors.
A pivotal Phase III trial in the refractory/relapsed MDS clinical program is underway in the U.S. andEurope..
SymBio is now preparing to initiate a Phase I clinical trial in Japan and Korea for the treatment ofrefractory/relapsed MDS patients using the intravenous form (SyB L-1101) of rigosertib, with thetreatment of frontline MDS using the oral form (SyB C-1101) to follow based on results generated in US
Phase II clinical trials.

[Please see the following for further information on Onconova ][Contact]
Hiroki Maekawa
Board Director, Corporate Officer, Chief Financial Officer
Tel: +081(0)3 5472 1125
Note to Editors

About Myelodysplastic Syndrome (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 and the disease commonly affects the elderly.

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 450 patients with solid tumors and hematologicalcancers, including MDS and AML. MDS and AML are blood disorders widely recognized as difficult tomanage with limited therapeutic options available for patients, especially those with drug-resistantdisease. Onconova’s multi-site Phase III ONTIME trial in MDS patients is under a Special ProtocolAssessment (SPA) from the U.S. FDA and is being supported by an award from the Therapeutics
Acceleration Program (TAP) of the Leukemia and Lymphoma Society (LLS). FDA has granted Orphan
Drug Designation for the use of rigosertib in MDS. The clinical program in solid tumors is also
advancing with initiation of the Phase II/III combination ONTRAC trial (ON 01910.Na TRial in Patientswith Advanced Pancreatic Cancer) and Phase II single agent trial in ovarian cancer. A U.S. patent
covering ON 01910.Na is issued 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 DNA
repair. These candidates are derived from a proprietary new chemical entities and non-ATP
competitive chemotypes. In addition to rigosertib sodium (ON 01910.Na), Onconova is developing twoother products 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 inhibitorsof Plk2, ALK, CDK, JAK, and Bcr-Abl pathways and a novel immunoconjugate platform for arming
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 the areas of oncology, hematology and autoimmune. 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. The product has been launched in Hong Kong, Singapore and Korea,
with market approval recently granted in Taiwan. For additional information, please visit our homepage
at http://www.symbiopharma.com.