October 17, 2018
SymBio Pharmaceuticals Limited
Fuminori Yoshida
Representative Director
President and Chief Executive Officer(Securities Code: 4582)

Onconova Announces Issuance of a New U.S. Patent for Rigosertib
TOKYO, Japan, October 17, 2018 -- SymBio Pharmaceuticals Limited (Headquarters: Tokyo,"SymBio,") announced today that its U.S. partner, Onconova Therapeutics, Inc. (Headquarters:Newtown, PA, “Onconova”) announced on October 17, 2018 that a new patent protecting rigosertib hasbeen issued by the United States Patent and Trademark Office (USPTO), extending U.S. patent
protection for rigosertib through 2037. Onconova plans to promptly apply for equivalent patents inboth Japan and Korea, where SymBio holds the exclusive license rights for the development andcommercialization of rigosertib.
For Onconova's full press release , please visit Onconova's website.
https://investor.onconova.com/press-releases
SymBio has been actively developing rigosertib (IV:injectable and oral formulations) for
myelodysplastic syndromes (MDS), for which there is high medical need. For rigosertib IV, SymBio
leads clinical development in Japan as part of an international phase III clinical trial conducted by
Onconova for patients with high-risk myelodysplastic syndrome (MDS) who have failed to respond tohypomethylating agents, relapsed after treatment, or were intolerant of hypomethylating agents. The
trial in Japan began in December 2015, and 37 patients have been enrolled as of the end of September
2018. For rigosertib oral, Onconova is conducting a phase I/II clinical trial targeting high-risk
myelodysplastic syndrome (MDS) for initial treatment (in combination with azacytidine) and a phase
II clinical trial targeting low-risk myelodysplastic syndrome (MDS), which is transfusion-dependent in
the United States. In June 2017, SymBio commenced a phase I clinical trial in Japan to confirm
tolerability and safety, and the trial has steadily progressed since the first patient enrollment inOctober 2017.

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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 development
candidates 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. In
addition 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 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 rights to develop and commercialize rigosertib in Japan and Korea from
Onconova in July 2011.
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 of
the 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).

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