Xenetic Biosciences, Inc.

Proxy Statement described below under “Additional Information and Where to Find It . ” You should not place undue reliance on these forward - looking statements, which are made only as of the date hereof or as of the dates indicated in the forward - looking statements . Xenetic Biosciences , Santersus and the combined company expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward - looking statements contained herein to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based . Xenetic Biosciences and Santersus obtained the industry, market and competitive position data used throughout this presentation from its own internal estimates and research, as well as from industry and general publications, and research, surveys and studies conducted by third parties . Internal estimates are derived from publicly available information released by industry analysts and third - party sources, Xenetic Biosciences and Santersus internal research and its industry experience, and are based on assumptions made by Xenetic Biosciences and Santersus based on such data and its knowledge of the industry and market, which it believes to be reasonable . In addition, while Xenetic Biosciences and Santersus believes the industry, market and competitive position data included in this presentation is reliable and based on reasonable assumptions, Xenetic Biosciences and Santersus has not independently verified any third - party information, and all such data involve risks and uncertainties and are subject to change based on various factors . This presentation contains trademarks, services marks, trade names and copyrights of Xenetic Biosciences and Santersus and other companies, which are the property of their respective owners . The use or display of third parties’ trademarks, service marks, trade name or products in this presentation is not intended to, and does not imply, a relationship with Xenetic Biosciences and Santersus , or an endorsement of sponsorship by Xenetic Biosciences and Santersus . Solely for convenience, the trademarks, service marks and trade names referred to in this presentation may appear with the ®, TM or SM symbols, but such references are not intended to indicate, in any way, that the company will not assert, to the fullest extent under applicable law, their rights or the right of the applicable licensor to these trademarks, service marks and trade name . Additional Information and Where to Find It This communication relates to the proposed acquisition transaction involving Xenetic Biosciences and Santersus and may be deemed to be solicitation material in respect of the proposed transaction. In connection with the proposed transac ti on, Xenetic Biosciences will file with the SEC a proxy statement (“Proxy Statement”) and Registration Statement on Form S - 1 (“Registration Statement”). INVESTORS AND SECURITY HOLDERS ARE URGED TO READ CAREFULLY THE PROXY STATEMENT, REGISTRATION STATEMENT, AND OTHER RELEVANT DOCUMENTS FILED OR WILL BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS THERETO AND ANY DOCUME NTS INCORPORATED BY REFERENCE THEREIN, IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION, RELATED MATTERS AND THE PARTIES TO TH E PROPOSED TRANSACTION. Investors and security holders may obtain a free copy of the Proxy Statement, the Registration Statement, and other relevant doc uments (if and when they become available) that are or will be filed with the SEC for free at the SEC’s website at www.sec.go v. Copies of the documents (when they become available) filed with the SEC by Xenetic Biosciences will be available free of charge on Xene tic Biosciences’ website at http://xeneticbio.com. Participants in the Solicitation Xenetic Biosciences and its directors and executive officers and Santersus and its directors and executive officers, may be deemed to be participants in the solicitation of proxies from the stockholde rs of Xenetic Biosciences in connection with the proposed transaction under the rules of the SEC. Information about the interests of the directors and executive officers of Xenetic Biosciences an d o ther persons who may be deemed to be participants in the solicitation of stockholders of Xenetic Biosciences in connection wi th the proposed transaction and a description of their direct and indirect interests, by security holdings or otherwise, will be included in the Proxy Statement related to the proposed transaction, which will be filed with the SEC. Additional information about Xenetic B io sciences, the directors and executive officers of Xenetic Biosciences and their ownership of Xenetic Biosciences common stock can also be f oun d in its Annual Report on Form 10 - K for the year ended December 31, 2025, as filed with the SEC on March 12, 2026, and its defin itive proxy statement, as filed with the SEC on October 31, 2025, and other documents subsequently filed by Xenetic Biosciences wit h t he SEC. Free copies of these documents may be obtained as described above. To the extent holdings of Xenetic Biosciences secu rit ies by its directors or executive officers have changed since the amounts set forth in such documents, such changes have been or are ex pected to be reflected on Initial Statements of