Regulation FD Disclosure. On September 23, 2026, Xenetic Biosciences, Inc. (“Xenetic”) released an updated investor presentation in connection with its pending share exchange transaction with Santersus AG (“Santersus”) as previously announced on September 16, 2026. Attached as Exhibit 99.1 is a copy of the updated investor presentation. The information in this Item 7.01, including Exhibit 99.1 attached hereto, is being furnished, shall not be deemed “filed” for any purpose, and shall not be d…

Unregistered Sales of Equity Securities. The disclosure contained in

Entry into a Material Definitive Agreement. Share Exchange Agreement On September 14, 2026, Xenetic Biosciences, Inc., a Nevada corporation (“Xenetic” or the “Company”), entered into a Share Exchange Agreement (the “Exchange Agreement”) with Santersus AG, a Swiss corporation ( Aktiengesellschaft ) (“Santersus”), the sellers listed on Schedule I thereto (each, a “Seller,” and collectively with the holders of Santersus securities who subsequently become parties to the Exchange Agreement, the “S…

Regulation FD Disclosure. Attached as Exhibit 99.1 is a copy of the joint press release issued by Xenetic and Santersus on September 16, 2026 announcing the execution of the Exchange Agreement. Xenetic and Santersus will host a joint conference call and webcast on September 16, 2026 at 8:30 a.m. Eastern Time to discuss the proposed Acquisition. A copy of the slide presentation to be used during the joint conference call is attached hereto as Exhibit 99.2. The information in this Item 7.01, in…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

James Parslow: Compensatory arrangement and equity grant to an existing officer.

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

Entry into a Material Definitive Agreement. On October 10, 2025, Xenetic Biosciences, Inc., a Nevada corporation (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Canaccord Genuity LLC as representative of the several underwriters named therein, relating to an underwritten public offering (the “Offering”) of 735,000 shares (the “Shares”) of the Company’s common stock, par value $0.001 per share, at a public offering price of $6.12 per share. The Offeri…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

Changes in Registrant’s Certifying Accountant. (a) Resignation of Independent Registered Public Accounting Firm On November 1, 2024, CBIZ CPAs P.C. (“CBIZ”) acquired the attest business of Marcum LLP (“Marcum”). On April 8, 2025, Xenetic Biosciences, Inc. (the “Company”) was notified by Marcum that Marcum resigned as the Company’s independent registered public accounting firm as a result of such acquisition, and the Company’s Audit Committee approved the resignation. The audit report of Marcu…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

Entry into a Material Definitive Agreement. On November 1, 2024, Xenetic Biosciences, Inc. (the “Company”) and The Scripps Research Institute (“Scripps Research”) entered into a Second Amendment to Research Funding and Option Agreement (the “Amendment”), pursuant to which the Company amended that certain Research Funding and Option Agreement, dated March 17, 2023, by and between the Company and Scripps (the “Original Agreement”), in order to extend the term of the Original Agreement for an ad…

Director — James E. Callaway and Adam Logal: Dr. Callaway and Mr. Logal informed the Company of their intention to not stand for re-election at the 2024 Annual Meeting.

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

Chief Executive Officer — Jeffrey F. Eisenberg: The former CEO, Jeffrey F. Eisenberg, departed the company and entered into a separation agreement.

Chief Executive Officer — Jeffrey F. Eisenberg: Mr. Eisenberg stepped down as CEO and resigned from the board.

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

by reference. The information in this Item 2.02, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing. FORWARD-LOOKING STATEMENTS This Form 8-K, including the press release, contains forward-looking statements that we…

Material Modification to Rights of Security Holders. To the extent required by