August 14, 2014
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer

Onconova’s Announcement in the Development of Rigosertibfor patients with MDS in Second Quarter 2014
TOKYO, Japan, August 12, 2014 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo, “SymBio”)
announced today that Onconova Therapeutics, Inc. (Headquarters: Newtown, PA, “Onconova”) has
discussed plans for further development of rigosertib for patients with myelodysplastic syndromes(“MDS”) in their announcement of second quarter 2014 financial and operational results.

After Onconova’s announcement in February 2014 regarding the top-line results of the Phase 3
ONTIME trial of IV rigosertib in higher risk MDS (“HR-MDS”), Onconova has continued discussions withUS and European regulatory agencies.

As a result, the discussions with the FDA and several European regulatory agencies have led
Onconova to focus its development efforts for the unmet medical need in patients who do not respond toinitial treatment with the current standard of care hypomethylating agents (“Primary HMA Failure”).
Onconova plans to announce development plan for IV rigosertib in HR-MDS in the fourth quarter of 2014
following additional regulatory discussions.

SymBio will investigate its IV rigosertib development plan for Japan and Korea by contemplating
Onconova’s IV rigosertib in HR-MDS development plan which will be announced in due course.

Onconova has also announced progress in development of oral rigosertib; (1) a pivotal study of oral
rigosertib in Lower Risk MDS is now expected to commence in the first half of 2015 and (2) In a phase
1/2 study to evaluate the potential synergetic activity of rigosertib and azacitidine, the phase 2 portion ofthis trial has commenced following successful completion of the Phase 1 portion of this study. The Phase
2 portion is being conducted at multiple sites in the US and Europe.

[For more information, please visit Onconova’s website at http://investor.onconova.com/releases.cfm]

[Please read the following for more information on MDS, rigosertib, and Onconova][Contact]
Investor Relations, Corporate Planning Department
Tel: +81(0)3 5472 1125
About Onconova Therapeutics, Inc.
Onconova Therapeutics is a clinical-stage biopharmaceutical company focused on discovering anddeveloping novel products to treat cancer. Onconova's clinical and pre-clinical stage drug development
candidates are derived from its proprietary chemical library and are designed to work against specificcellular pathways that are important in cancer cells, while causing minimal damage to normal cells. In
addition to rigosertib, the Company's most advanced product candidate, two other candidates, bricicliband recilisib, are in clinical trials, and several candidates are in pre-clinical stages. For more information,please visit http://www.onconova.com.

About Rigosertib
Rigosertib is a small molecule inhibitor of two important cellular signaling pathways, phosphoinositide
3-kinase, or PI3K, and polo-like kinase, or PLK, both of which are frequently activated in cancer cells.
Recently, it was shown that rigosertib inhibits these pathways by interacting with the Ras Binding
Domain (RBD) of several signaling molecules. Due to the dual effect of inhibiting PI3K and PLK
pathways, rigosertib has shown activity in a variety of cancers including solid tumors and hematologicalmalignancies. Clinical trials with IV and oral formulations of rigosertib have been conducted at leading
institutions in the US and abroad. To date, more than 1,100 patients with solid tumors or hematologicaldiseases have been enrolled in clinical trials with rigosertib.

Rigosertib has been granted orphan drug

status for MDS in the US, Europe and Japan. Rigosertib is being developed in partnership with Baxter
International (commercialization rights in Europe) and SymBio Pharmaceuticals (Japan and Korea).
Onconova has retained all other territories for commercialization.