Theriva Biologics sold assets for $350k

Item 1.01. Entry into a Material Definitive Agreement.

On October 30, 2026 (the "Effective Date"),

Theriva Biologics, Inc. (the "Company") entered into an Asset Purchase and Sale Agreement (the "Purchase Agreement") with Biossil Labs Inc., a corporation organized under the laws of Canada (the "Biossil"), pursuant to which the Company sold to Biossil, and Biossil purchased from the Company, the Company's assets exclusively relating to SYN-004 (ribaxamase), the Company's oral β-lactamase product candidate, including its improvements, modifications and reformulations, including SYN-007 (collectively, "Ribaxamase"), as well as certain assets exclusively related to SYN-006, the Company's carbapenemase product candidate (collectively, the "Purchased Assets"). The closing of the transaction (the "Closing") occurred concurrently with the execution of the Purchase Agreement on the Effective Date².

The Purchased Assets include, among other things, the patents and other intellectual property relating exclusively to Ribaxamase¹, specified contracts, regulatory filings and approvals (including an investigational new drug application), existing inventory and materials, books, records and data, related claims and rights of recovery, and the specified SYN-006 assets. Biossil assumed only specified liabilities, consisting generally of liabilities arising after the Closing from Biossil's ownership or exploitation of the Purchased Assets³ and post-Closing obligations under the assumed contracts. The Company retained all other liabilities, including liabilities arising from its ownership or exploitation of the Purchased

Assets prior to the Closing. All cash, contracts not assumed by Biossil, intellectual property other than the purchased intellectual property, and certain other assets were excluded from the sale. At the Closing, the Company also granted Biossil a non-exclusive, perpetual, irrevocable, worldwide, fully paid-up, royalty-free license under certain Company intellectual proper

Item 2.01. Completion of Acquisition or Disposition of Assets.

The information set forth in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 2.01. The Closing occurred on October 30, 2026.

Item 7.01. Regulation FD Disclosure.

On November 2, 2026, the Company issued a press release announcing the Agreement⁴, a copy of which is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

The information in this Item 7.01 and in the press release attached as Exhibit 99.1 to this Current Report on Form 8-K shall not be deemed to be "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended⁶, or otherwise subject to the liabilities of that section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended. The information contained in this Item 7.01 and in the press release furnished as Exhibit 99.1 to this Current Report on Form 8-K shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

The press release furnished as Exhibit 99.1 to this Current Report on Form 8-K includes "safe harbor" language pursuant to the Private Securities Litigation Reform⁵

Act of 1995, as amended, indicating that certain statements contained therein are "forward-looking" rather than historical⁵.

The Company undertakes no duty or obligation to update or revise the information contained in this Current Report on Form 8-K, although it may do so from time to time if its management believes it is appropriate. Any such updating may be made through the filing of other reports or documents with the Securities and Exchange Commission, through press releases or through other public disclosures.

Forward-Looking Statements

This Current Report on Form 8-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding the potential receipt of milestone, royalty and license consideration payments under the Purchase Agreement and the development, regulatory approval and commercialization of the products.