Company: INTS
Filing Date: 2025-06-18
Form Type: 424B5
Source: 0001628280-25-032094
Chunk: 0

Company: INTENSITY THERAPEUTICS, INC.
Filing Date: 2025-06-18
Form: 424B5
Chunk 0
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#### Filed Pursuant to Rule 424(b)(5)

#### Registration No. 333-280681

#### PROSPECTUS SUPPLEMENT No. 3
(To the Sales Agreement Prospectus dated July 11, 2024 and

#### the Base Prospectus, dated July 11, 2024)

#### INTENSITY THERAPEUTICS, INC.

#### Up to $9,650,000

#### Common Stock
We have previously entered into an at the market offering agreement (the “Offering Agreement”) with H.C. Wainwright & Co., LLC (“Wainwright”) relating to shares of our common stock offered by this prospectus supplement and the sales agreement prospectus dated July 11, 2024 (the “July 11, 2024 sales agreement prospectus”) and the base prospectus dated July 11, 2024 (the “July 11, 2024 prospectus”). In accordance with the terms of the Offering Agreement, we may offer and sell shares of our common stock, $0.0001 par value per share, from time to time through Wainwright acting as our agent (the “ATM Offering”).

Our common stock is listed on The Nasdaq Capital Market under the symbol “INTS.” On June 17, 2025, the last reported sale price of our common stock on The Nasdaq Capital Market was $0.2859 per share.

We are filing this prospectus supplement to supplement and amend, as of June 18, 2025, the July 11, 2024 sales agreement prospectus and July 11, 2024 base prospectus to increase the maximum aggregate gross sales price of our common stock that may be offered, issued and sold under the Offering Agreement from and after the date hereof to $9,650,000 (the “ATM Offering Size Increase”), not including the shares of common stock previously sold. Under the July 11, 2024 sales agreement prospectus, we initially registered up to $15,000,000 of our common stock for offer and sale pursuant to the Offering Agreement, which was reduced to $7,000,000 on November 20, 2024, and further reduced to $15,000 on June 11, 2025. As of the date of the filing of this prospectus supplement, we have sold 193,816 shares of our common stock that are covered by the July 11, 2024 sales agreement prospect