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Press Release


Bayer's Stivarga Patent Challenged in Inter Partes Review

SAN FRANCISCO, July 27, 2016 /PRNewswire/ -- Fustibal LLC (Fustibal), a targeted therapeutics biotechnology startup, today announced that it has filed an inter partes review (IPR) petition of United States Patent No. 8,637,553 (the '553 patent) owned by Bayer Healthcare LLC (Bayer) with the Patent Trial and Appeal Board (PTAB). The petitioner challenges the validity of the '553 patent and requests that all claims be found unpatentable and canceled.

The '553 patent currently provides the pharmaceutical drug Stivarga® (regorafenib) FDA Orange Book exclusivity through February 16, 2031. The structure of the claimed compound regorafenib is identical to that of its predecessor compound sorafenib (Nexavar® also by Bayer) but for the substitution of a single fluorine atom. Stivarga, one of Bayer's best-selling pharmaceuticals products, is a FDA-approved oral multi-kinase inhibitor for the treatment of select patients with colorectal cancer and gastrointestinal stromal tumors. Regorafenib is the active pharmaceutical ingredient used in Bayer's Stivarga and a leading drug candidate for Fustibal's Drug Targeting Platform.

"We believe that the patent in question is invalid and thwarts the spirit of innovation," stated Dr. David Tran, Founding Scientist at Fustibal. "The IPR process is being utilized to clear questionable intellectual property rights that would unduly delay the development of our novel antibody-based drug for multi-targeted cancer therapy. We believe oncology products should be developed and accessible to all cancer patients, not only for those patients who can afford it. We look forward to the uninterrupted development of medicine, whether innovative or generic, and the submission of New Drug Application (NDA) and Abbreviated NDA (ANDA) for future formulations."

The first petition for inter partes review is assigned the processing number IPR2016-01490 by the United States Patent and Trademark Office's PTAB.

About Fustibal

Fustibal is a biotechnology company focused on fostering affordable healthcare through simpler science. To evolve the medical industry, our team dissects life science big data through scientific investigation, reverse engineering, data mining, and computational science. In synergy with our Drug Targeting Platform, we design genomic- and proteomic-driven pharmaceuticals. Our mission is to develop data-based computational and accessible molecular diagnostics and therapeutics. Learn more at and


David Tran, PhD
(415) 935-4422


Bayer's regorafenib (Stivarga) vs sorafenib (Nexavar)

The contents of this press release were made available online July 26, 2016.

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