Entry into a Material Definitive Agreement. On August 21, 2026, OS Therapies Incorporated (the “Company”) entered into an Open Market Sale Agreement℠ (the “Sales Agreement”) with Jefferies LLC (the “Sales Agent”), pursuant to which the Company may offer and sell shares of its common stock from time to time through or to the Sales Agent in connection with the Company’s “at the market offering” program (the “ATM Offering”). On August 21, 2026, the Company filed with the Securities and Exchange…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth under

The Shares, Notes, Warrants, Pre-Funded Warrants and Placement Agent Warrants, and the shares of the Company’s common stock issuable upon conversion of the Notes and exercise of the Warrants, Pre-Funded Warrants and Placement Agent Warrants, were offered and sold by the Company in reliance upon an exemption from the registration requirements of the Securities Act afforded by Section 4(a)(2) thereof and/or Regulation D promulgated thereunder. Each Purchaser represented that it is an “accredite…

Entry into a Material Definitive Agreement. Securities Purchase Agreement On August 10, 2026, OS Therapies Incorporated (the “Company”), together with its wholly owned subsidiaries, entered into a securities purchase agreement (the “Purchase Agreement”) with the purchasers signatory thereto (each, a “Purchaser” and, collectively, the “Purchasers”), pursuant to which the Company agreed to issue and sell to the Purchasers, in a private placement (the “August Private Placement”), senior secured…

The Bridge Note was offered and sold by the Company in reliance upon an exemption from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”), afforded by Section 4(a)(2) thereof and/or Regulation D promulgated thereunder. The purchaser of the Bridge Note represented that it is an “accredited investor” as defined in Rule 501(a) under the Securities Act.

Entry into a Material Definitive Agreement. Leonite 2026 Secured Financing As previously disclosed, on June 30, 2026, OS Therapies Incorporated (the “Company”), together with its wholly owned subsidiaries, entered into a securities purchase agreement (the “Leonite SPA”) with Leonite Fund I, LP (“Leonite”) and related transaction documents, pursuant to which the Company issued and sold to Leonite, in a private placement (the “Leonite Private Placement”), a senior secured convertible promissory…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth under

Termination of a Material Definitive Agreement. On July 23, 2026, OS Therapies Incorporated (the “Company”) delivered to B. Riley Securities, Inc. and JonesTrading Institutional Services LLC (together, the “Sales Agents”) written notice of termination of the At Market Issuance Sales Agreement, dated August 8, 2025 (the “Sales Agreement”), between the Company and the Sales Agents, pursuant to Sections 13(b) and 14 thereof. The termination became effective on July 28, 2026. As previously disclo…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth under

Director — Karim Galzahr: Mr. Galzahr resigned from the board of directors, and Dr. Craig Eagle was appointed to fill the vacancy.

Entry into a Material Definitive Agreement. On June 30, 2026, OS Therapies Incorporated (the “Company”), together with OS Animal Health Inc. (“OSAH”) and OS Therapies UK Ltd (“OSUK” and, collectively, the “Borrowers”), each a wholly owned subsidiary of the Company, entered into a securities purchase agreement (the “Purchase Agreement”) with Leonite Fund I, LP (the “Investor”), pursuant to which the Company agreed to issue and sell to the Investor, in a private placement (the “Private Placemen…

Other Events. On July 2, 2026, the Company issued a press release announcing the Private Placement and the appointment of Dr. Eagle to the Company’s board of directors, a copy of which is attached hereto as Exhibit 99.1 and is incorporated herein by reference. Forward-Looking Statements This Current Report on Form 8-K, including Exhibit 99.1 hereto, contains forward-looking statements that involve risks and uncertainties, such as statements related to the intended use of the net proceeds from…

The Securities are being offered and sold by the Company in reliance upon an exemption from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”), afforded by Section 4(a)(2) thereof and/or Regulation D promulgated thereunder. The Investor represented that it is an “accredited investor” as defined in Rule 501(a) under the Securities Act.

Entry into a Material Definitive Agreement. Securities Purchase Agreement On March 31, 2026, OS Therapies Incorporated (the “Company”) entered into a securities purchase agreement (the “Purchase Agreement”) with the purchasers identified on the signature pages thereto (the “Purchasers”), pursuant to which the Company offered for sale to the Purchasers in a registered direct offering (the “Offering”) an aggregate of 2,505,073 shares of its common stock and, in lieu thereof, pre-funded warrants…

Other Events. On March 31, 2026, OS Therapies Incorporated (the “Company”) filed with the U.S. Securities and Exchange Commission (the “SEC”) a prospectus supplement (the “Prospectus Supplement”), which forms a part of the Company’s registration statement on Form S-3 (File No. 333-289443), which was previously filed with the SEC on August 8, 2025 and declared effective on August 12, 2025. The Prospectus Supplement covers the resale from time to time of up to 10,529,417 shares of the Company’s…

Entry into a Material Definitive Agreement. Private Placement On March 4, 2026, OS Therapies Incorporated (the “Company”) entered into a securities purchase agreement (the “Purchase Agreement”) with certain accredited investors (collectively, the “Purchasers”), pursuant to which the Company agreed to issue and sell to the Purchasers, in a private placement (the “Private Placement”), (i) 10.0% original issue discount unsecured convertible promissory notes (the “Notes”) and (ii) warrants to pur…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth under

The Notes, Warrants and Underlying Shares are being offered and sold by the Company in reliance upon an exemption from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”), afforded by Section 4(a)(2) thereof and/or Regulation D promulgated thereunder. The Purchasers represented that they are “accredited investors” as defined in Rule 501(a) under the Securities Act.

The New Warrants and New Warrant Shares are being offered and sold by the Company in reliance upon an exemption from the registration requirements of the Securities Act afforded by Section 4(a)(2) of the Securities Act and Rule 506(b) of Regulation D promulgated thereunder.

Entry into a Material Definitive Agreement. Warrant Exercise Inducement On January 10, 2026, OS Therapies Incorporated (the “Company”) entered into inducement offer letter agreements (the “Inducement Letters”) with less than 10 accredited investors (the “Holders”) that hold certain existing warrants of the Company to purchase up to an aggregate of 5,382,148 shares of the Company’s common stock, originally issued to the Holders in connection with the Company’s previous warrant exercise inducem…

The filing pertains to an amendment of the Company's incentive compensation plan, which is a routine corporate action.

Other Events. On September 30, 2025, OS Therapies Incorporated (the “Company”) filed with the U.S. Securities and Exchange Commission (the “SEC”) a prospectus supplement (the “Prospectus Supplement”), which forms a part of the Company’s registration statement on Form S-3 (File No. 333-289443), which was previously filed with the SEC on August 8, 2025 and declared effective on August 12, 2025. The Prospectus Supplement covers the resale from time to time of up to 4,373,043 shares of the Compan…

Entry into a Material Definitive Agreement. Warrant Exercise Inducement On September 2, 2025, OS Therapies Incorporated (the “Company”) closed on a second warrant exercise inducement and exchange offer (the “Offering”). The Offering was made to remaining holders (the “Remaining Holders”) of the existing warrants of the Company to purchase shares of the Company’s common stock, having a current exercise price of $1.12 per share, originally issued to the Remaining Holders on December 31, 2024 an…

The New Warrants and New Warrant Shares were offered and sold by the Company in reliance upon an exemption from the registration requirements of the Securities Act afforded by Section 4(a)(2) of the Securities Act and Rule 506(b) of Regulation D promulgated thereunder.

Termination of a Material Definitive Agreement. On August 25, 2025, OS Therapies Incorporated (the “Company”) delivered to Square Gate Capital Master Fund, LLC — Series 3 (“Square Gate”) a notice to terminate the Equity Purchase Agreement, dated as of October 31, 2024 (the “ELOC Purchase Agreement”), pursuant to Section 10.6 thereof. The termination became effective on August 26, 2025. As previously disclosed, the ELOC Purchase Agreement provided the Company with the right to sell to Square G…