Dicerna Announces Patent Issuance for DsiRNAs Directed at the KRAS Gene, a Key Cancer Regulator

March 19, 2013

WATERTOWN, Mass. – March 19, 2013 – Dicerna Pharmaceuticals, Inc. (Dicerna), a second generation RNA interference (RNAi) company developing novel therapeutics utilizing its proprietary Dicer Substrate Technology™ and Dicer Substrate siRNA (DsiRNA) molecules, today announced that the United States Patent and Trademark Office (USPTO) has issued patent claims specific to double-stranded RNAs directed against the important oncology gene target KRAS. U.S. patent 8,372,816, titled “Methods and compositions for the specific inhibition of KRAS by asymmetric double-stranded RNA” was recently issued to Dicerna. This issuance continues the expansion of Dicerna’s patent portfolio around RNAi-related technology, including the DsiRNA class defining claims of U.S. patent 8,084,599, titled “Methods and compositions for the specific inhibition of gene expression by double-stranded RNA.”

“We are extremely pleased the USPTO has granted these most recent patent claims specific to the KRAS gene, further adding to our strong patent estate and allowing for broad therapeutic use claims in the RNAi field,” said Douglas Fambrough, chief executive officer of Dicerna. “The KRAS gene has been recognized as a target of great therapeutic potential for decades, and yet has remained undruggable. The successful application of Dicer Substrate Technology against KRAS is a key advancement that could lead to important new therapeutics for cancer treatment.”

On February 26, 2013, scientists from Kyowa Hakko Kirin Co., Ltd. (KHK) presented a talk entitled “Development of Lipid Nanoparticle (LNP) Based Delivery System of siRNA Targeting Extrahepatic Tumor,” at Asia TIDES: Oligonucleotide and Peptide Research, Technology and Product Development. The presentation highlighted in vivo tumor efficacy data obtained with DsiRNA targeting the KRAS gene, one of the programs from the research and development collaboration between Dicerna and KHK. The partners had previously announced in December 2011 that KHK had elected to advance this first collaborative therapeutic oncology candidate from the research stage into formal development studies, triggering a $5 million milestone payment for Dicerna.

About Dicer Substrate RNAi
Dicer is a critical enzyme involved in the RNAi gene silencing cascade and acts as the natural
initiation point for this pathway by processing double-stranded RNA so that it can be used for gene silencing. Dicer then delivers these modified small RNA molecules to the mature gene silencing complex. Dicerna’s synthetic Dicer Substrate siRNA (DsiRNA) molecules are 25 or more base pairs in length and are processed by Dicer. By utilizing this distinct early entry point into the pathway, DsiRNA molecules have greater potency and longer duration of action than other RNAi approaches. In addition, DsiRNA molecules have enhanced delivery potential because their structure creates a natural conjugation point for cellular targeting agents.

About Dicerna Pharmaceuticals
Dicerna Pharmaceuticals is a private, venture-backed RNAi-focused biopharmaceutical company
developing novel therapeutic agents and related drug delivery systems in oncology and other disease areas based on its proprietary Dicer Substrate Technology™ platform and Dicer Substrate siRNA (DsiRNA) molecules. Dicer Substrate Technology™ is a second generation RNAi approach that results in greater potency, longer duration of action and enhanced delivery potential, differentiating it from other RNAi approaches. Dicerna has a major alliance with Kyowa Hakko Kirin for DsiRNA pharmaceuticals and drug delivery systems focused in oncology, immunology and inflammation. The company also has a partnership with Ipsen to research and develop novel DsiRNA therapeutics with targeted delivery in oncology and endocrinology. Dicerna is based in Watertown, Massachusetts. For more information, please visit www.dicerna.com.

About Kyowa Hakko Kirin
Kyowa Hakko Kirin is a leading biopharmaceutical company in Japan focusing on its core
business area of oncology, nephrology and immunology/allergy. Kyowa Hakko Kirin leverages antibody-related leading-edge technologies to discover and develop innovative new drugs aiming to become a global specialty pharmaceutical company which contributes to the health and well- being of people around the world.  For more information, visit http://www.kyowa-kirin.com.