EFTR eFFECTOR Therapeutics Inc (CE)

As filed with the Securities and Exchange Commission on July 30, 2024.

Registration No. 333-259751

Registration No. 333-262339

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 3 TO:

Form S-1 Registration No. 333-259751

POST-EFFECTIVE AMENDMENT NO. 1 TO:

Form S-1 Registration No. 333-262339

UNDER

THE SECURITIES ACT OF 1933

eFFECTOR Therapeutics, Inc.

(Exact name of registrant as specified in its charter)

124 Washington Street, Suite 101

Foxboro, MA 02035

(508) 543-1720

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

Craig Jalbert

Chief Executive Officer

124 Washington Street, Suite 101

Foxboro, MA 02035

(508) 543-1720

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

Copies to:

Cheston Larson

Matthew T. Bush

Anthony Gostanian

Latham & Watkins LLP

12670 High Bluff Drive

San Diego, California

92130

(858) 523-5400

Approximate date of commencement of proposed sale to the public: This post-effective amendment is being filed to deregister all of the unsold securities previously registered under the Registration Statements.

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. ☒

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, 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. ☐

DEREGISTRATION OF SECURITIES

This Post-Effective Amendment relates to the following Registration Statements on Form S-1 (the “Registration Statements”), filed with the Securities Exchange Commission (the “SEC”) by eFFECTOR Therapeutics, Inc. (the “Registrant”):

The Registrant is filing this Post-Effective Amendment to deregister any and all securities that remain unsold under the Registration Statements as of the date hereof. In accordance with the undertakings made by the Registrant in the Registration Statements to remove from registration by means of a post-effective amendment any securities that had been registered for issuance but remain unsold at the termination of the offering, the Registrant hereby removes and withdraws from registration any and all securities registered pursuant to the Registration Statements that remain unsold as of the date hereof.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-1 and has duly caused this Post-Effective Amendment to the Registration Statements on Form S-1 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Foxboro, State of Massachusetts, on July 30, 2024.

No other person is required to sign this Post-Effective Amendment in reliance upon Rule 478 under the Securities Act of 1933.