Entero Therapeutics, Inc.

S-11 tm2524242d1_s1.htm FORM S-1

As filed with the Securities and Exchange Commission on****August 26, 2025

Registration Statement No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

ENTERO THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

777 Yamato Road, Suite 502

Boca Raton, Florida 33431

(561) 589-7020

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Richard Paolone

Interim Chief Executive Officer

ENTERO THERAPEUTICS, INC.

777 Yamato Road, Suite 502

Boca Raton, Florida 33431

(561) 589-7020

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Ross Carmel, Esq.

Avital Perlman, Esq.

Sichenzia Ross Ference Carmel LLP

1185 Avenue of the Americas, 31 st** Floor**

New York, NY 10036

(212) 930-9700

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.¨

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.¨

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission acting pursuant to said Section 8(a), may determine.

The information contained in this preliminary prospectus is not complete and may be changed. The selling stockholders listed herein may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED****AUGUST 26, 2025

PRELIMINARY PROSPECTUS

4,945,510 Shares of Common Stock

The selling stockholders named in this prospectus may use this prospectus to offer and resell from time to time up to an aggregate of 4,945,510 shares of our common stock, par value $0.0001 per share (the “Common Stock”), which are comprised of (i) 1,626,282 shares of common stock issuable upon exercise of pre-funded warrants (the “Pre-funded Warrants”) and (ii) 3,319,228 shares of common stock issuable upon exercise of common warrants (the “Common Warrants” and collectively with the Pre-funded Warrants, the “Warrants”) issued by us in a private placement to the selling stockholders that are party to the Securities Purchase Agreement, dated August 9, 2025 (the “Purchase Agreement”). The shares of common stock issuable upon exercise of the Warrants are collectively referred to herein as the “Shares”.

We are not selling any shares of our common stock under this prospectus and will not receive any of the proceeds from the sale of the Shares by the selling stockholders. We will, however, receive the net proceeds of any Warrants exercised for cash.

The selling stockholders may sell or otherwise dispose of the Shares in a number of different ways and at varying prices. We provide more information about how the selling stockholders may sell or otherwise dispose of the Shares covered by this prospectus in the section entitled “Plan of Distribution” on page 29. Discounts, concessions, commissions and similar selling expenses attributable to the sale of the Shares will be borne by the selling stockholders. We will pay all expenses (other than discounts, concessions, commissions and similar selling expenses) relating to the registration of the Shares with the Securities and Exchange Commission (the “SEC”).

Except for the financial statements from the Annual Report on Form 10-K for the year ended December 31, 2024 and the Quarterly Reports on Form 10-Q for the quarters ended March 31, 2025 and June 30, 2025, which are incorporated by reference herein, all historical share and per share information in this prospectus gives retroactive effect to a 1-for-3 reverse split of our common stock that became effective on August 18, 2025.

Our common stock is listed on the Nasdaq Capital Market under the symbol “ENTO”. On August 25, 2025, the last reported sale price of our common stock on the Nasdaq Capital Market was $2.05 per share.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page****19 of this prospectus and under similar headings in the documents incorporated by reference into this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed on the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is[ ], 2025

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