Xenetic Biosciences Strengthens Technology Patent Portfolio

LEXINGTON, Mass., June 9, 2014 (GLOBE NEWSWIRE) -- Xenetic Biosciences, Inc. (OTCBB:XBIO), a biopharmaceutical company focused on developing next-generation biologic drugs and novel oncology therapeutics, today announced that the U.S. Patent and Trademark Office has granted U.S. Patent No. 8,735,557, entitled "Activated Sialic Acid Derivatives for Protein Derivatization and Conjugation," with claims that cover lead compound, ErepoXen®, and Xenetic's broader polysialic acid technologies.

"This newly issued patent further fortifies and extends our robust patent portfolio covering the PolyXen® delivery technology platform, including our lead product candidate, ErepoXen®," said Scott Maguire, Chief Executive Officer of Xenetic. "This patent is one of thirteen patents allowed or issued in the last three months, and demonstrates Xenetic's recent efforts to protect our broad and unique intellectual property both domestically and abroad. We now have over 140 issued patents that serve as the foundation for our drug developments."

ErepoXen® is a polysialylated form of erythropoietin (EPO), a hormone produced by the kidneys to maintain red blood cell production and prevent anaemia. Chronic renal failure or chemotherapy can cause anaemia. ErepoXen is a polysialylated form of EPO designed to reduce the required frequency of dosage, side effects and to be less immunogenic than existing treatments. Clinical results of ErepoXen suggest that the drug candidate can be administered once a month. ErepoXen is currently in Phase 2/3 clinical development in collaboration with the Serum Institute of India and SynBio.

About Xenetic Biosciences

Xenetic Biosciences is a biopharmaceutical company developing next-generation biologic drugs and novel oncology therapeutics. Xenetic's proprietary drug technology platforms include PolyXen® for creating next generation biologic drugs by extending the efficacy, safety and half-life of biologic drugs and OncoHist® for the development of novel oncology drugs focused on orphan indications. Xenetic's lead product candidates include ErepoXen®, an improved, polysialylated form of erythropoietin (EPO) for the treatment of anemia in pre-dialysis patients with chronic kidney disease and OncoHist®, a recombinant human histone H1.3 molecule which Xenetic is developing for the treatment of refractory Acute Myeloid Leukemia (AML). Xenetic is developing a novel series of polysialylated blood coagulation factors through its license agreement with Baxter International Inc. Xenetic is also developing a broad pipeline of clinical candidates for next generation biologics and novel oncology therapeutics in a number of orphan disease indications. For more information, please visit the company's website at www.xeneticbio.com.

Forward-Looking Statements

This release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by terminology such as "anticipate," "believe," "could," "could increase the likelihood," "estimate," "expect," "intend," "is planned," "may," "should," "will," "will enable," "would be expected," "look forward," "may provide," "would" or similar terms, variations of such terms or the negative of those terms. Any forward-looking statements in this press release are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to, the risk of cessation or delay of any of the ongoing or planned clinical trials and/or our development of our product candidates, the risk that the results of previously conducted studies involving similar product candidates will not be repeated or observed in ongoing or future studies involving current product candidates, the risk that our collaboration with Baxter will not continue or will not be successful, and the risk that any one or more of our product candidates will not be successfully developed and commercialized. For a discussion of other risks and uncertainties, and other important factors, any of which could cause our actual results to differ from those contained in the forward-looking statements, see the section entitled "Risk Factors" in our Annual Report on Form 10-K, as well as discussions of potential risks, uncertainties, and other important factors in our subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Xenetic undertakes no duty to update this information unless required by law.

CONTACT: Xenetic Biosciences Inc.
         www.xeneticbio.com
         M. Scott Maguire, Chief Executive Officer
         781 778 7720
         j.mccusker@xeneticbio.com

         US Contact:
         Stern Investor Relations
         Paul Cox
         212 362 1200
         paul@sternir.com

         UK/European contact:
         Walbrook PR
         Mike Wort
         +44 (0)20 7933 8780
         mike.wort@walbrookpr.com

Released June 9, 2014