As filed with the Securities and Exchange Commission on October 22, 2020

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ITERUM THERAPEUTICS PLC

(Exact name of registrant as specified in its charter)

Block 2 Floor 3, Harcourt Centre,

Harcourt Street,

Dublin 2,

Ireland

+353 1 9038920

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

Corey N. Fishman

President and Chief Executive Officer

200 South Wacker Drive, Suite 2550

Chicago, Illinois 60606

(312) 778-6070

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

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement is declared effective.

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.  ☒    333-249432

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.  ☒

CALCULATION OF REGISTRATION FEE

The Registration Statement shall become effective upon filing in accordance with Rule 462(b) under the Securities Act of 1933, as amended.

EXPLANATORY NOTE AND INCORPORATION BY REFERENCE

This registration statement is being filed with respect to the registration of (i) additional ordinary shares, nominal value $0.01 per share (each an “Ordinary Share”), together with a warrant to purchase 0.75 of an Ordinary Share (each a “Warrant”), (ii) additional pre-funded warrants to purchase one Ordinary Share (each a “Pre-funded Warrant”), together with a Warrant and (iii) additional placement agent warrants to purchase 7.0% of the aggregate number of Ordinary Shares and Pre-funded Warrants being offered (each a “Placement Agent Warrant”), of Iterum Therapeutics plc, an Irish public limited company, as set forth in the Registration Statement and the prospectus contained therein, pursuant to Rule 462(b) under the Securities Act of 1933, as amended. The contents of the earlier registration statement on Form S-1, as amended (File No. 333-249432), which was declared effective by the Securities and Exchange Commission (the “Commission”) on October 22, 2020, are incorporated in this registration statement by reference.

The required opinions and consents are listed on an Exhibit Index attached hereto and filed herewith.

The registrant hereby certifies to the Commission that (i) it has instructed its bank to pay the Commission the filing fee set forth in the cover page of this registration statement by wire transfer of such amount to the Commission’s account as soon as practicable (but no later than the close of business on October 23, 2020); (ii) it will not revoke such instruction; and (iii) it has sufficient funds in the relevant account to cover the amount of such filing fee.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this Registration Statement on Form S-1 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Chicago, State of Illinois, on October 22, 2020.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated.