As filed with the Securities and Exchange Commission on December 9, 2020.

Registration No. 333-                

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ALX ONCOLOGY HOLDINGS INC.

(Exact name of Registrant as specified in its charter)

866 Malcolm Road, Suite 100

Burlingame, California 94010

650-466-7125

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

Jaume Pons, Ph.D.

Chief Executive Officer

ALX Oncology Holdings Inc.

866 Malcolm Road, Suite 100

Burlingame, California 94010

650-466-7125

(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 becomes 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, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☒ Registration No. 333-251171

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

This Registration Statement shall become effective upon filing in accordance with Rule 462(b) under the Securities Act.

EXPLANATORY NOTE AND INCORPORATION OF

CERTAIN INFORMATION BY REFERENCE

Pursuant to Rule 462(b) under the Securities Act of 1933, as amended, ALX Oncology Holdings Inc., a Delaware corporation, is filing this registration statement with the Securities and Exchange Commission (SEC). This registration statement relates to the public offering of securities contemplated by the Registration Statement on Form S-1, as amended (File No. 333-251171), which we originally filed on December 7, 2020 (the Earlier Registration Statement), and which the SEC declared effective on December 9, 2020.

We are filing this registration statement for the sole purpose of increasing the aggregate number of shares of common stock, par value $0.001 per share, offered by us by 437,000 shares, 57,000 of which are subject to purchase upon exercise of the underwriters’ option to purchase additional shares of common stock. The additional shares of common stock that are being registered for issuance and sale pursuant to this registration statement are in an amount and at a price that together represent no more than 20% of the maximum aggregate offering price set forth in the Calculation of Registration Fee table contained in the Earlier Registration Statement. The information set forth in the Earlier Registration Statement is incorporated by reference in this filing.

The required opinion and consents are listed on the Exhibit Index attached hereto and filed herewith.

EXHIBIT INDEX

II-1

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, 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 Burlingame, State of California, on the 9th day of December 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.

II-2

Exhibit 5.1

		Wilson Sonsini Goodrich & Rosati Professional Corporation 650 Page Mill Road Palo Alto, California 94304-1050 O: 650.493.9300 F: 650.493.6811

December 9, 2020

ALX Oncology Holdings Inc.

866 Malcolm Road, Suite 100

Burlingame, California 94010

Re: Securities Registered under Registration Statement on Form S-1 (File No. 333-251171) and Registration Statement filed pursuant to Rule 462(b) of the Securities Act of 1933, as amended (the “Securities Act”)

Ladies and Gentlemen:

This opinion is furnished to you in connection with the Registration Statement on Form S-1 (the “Registration Statement”), filed by ALX Oncology Holdings Inc. (the “Company”) with the Securities and Exchange Commission pursuant to Rule 462(b) of the Securities Act in connection with the registration under the Securities Act of 437,000 shares of the Company’s common stock, $0.001 par value per share (the “Shares”), including up to 57,000 shares issuable upon exercise of an option to purchase additional shares granted by the Company. The Registration Statement incorporates by reference the Registration Statement on Form S-1 (No. 333-251171) (the “Prior Registration Statement”), which was declared effective on December 9, 2020, including the prospectus which forms part of the Registration Statement. We understand that the Shares are to be sold by the Company to the underwriters for resale to the public as described in the Registration Statement and the Prior Registration Statement and pursuant to an underwriting agreement, substantially in the form filed as an exhibit to the Prior Registration Statement, to be entered into by and among the Company and the underwriters (the “Underwriting Agreement”).

We are acting as counsel for the Company in connection with the sale of the Shares by the Company. In such capacity, we have examined originals or copies, certified or otherwise identified to our satisfaction, of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary for the purposes of rendering this opinion. In our examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity with the originals of all documents submitted to us as copies, the authenticity of the originals of such documents and the legal competence of all signatories to such documents.

We express no opinion herein as to the laws of any state or jurisdiction other than the General Corporation Law of the State of Delaware (including the statutory provisions and all applicable judicial decisions interpreting those laws) and the federal laws of the United States of America.

AUSTIN        BEIJING        BOSTON         BRUSSELS        HONG KONG        LONDON        LOS ANGELES        NEW YORK        PALO ALTO

SAN DIEGO        SAN FRANCISCO        SEATTLE        SHANGHAI        WASHINGTON, DC        WILMINGTON, DE

December 9, 2020

Page 2

On the basis of the foregoing, we are of the opinion that the Shares to be issued and sold by the Company have been duly authorized and, when such Shares are issued and paid for in accordance with the terms of the Underwriting Agreement, will be validly issued, fully paid and nonassessable.

We consent to the use of this opinion as an exhibit to the Registration Statement, and we consent to the reference of our name under the caption “Legal Matters” in the prospectus forming part of the Prior Registration Statement, which is incorporated by reference into the Registration Statement.

Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

The Board of Directors

ALX Oncology Holdings Inc.:

We consent to the use of our report dated June 12, 2020, except for the retroactive effect of the reverse stock split as described under the heading ‘Reverse Stock Split’ in Note 4, which is as of July 13, 2020, with respect to the balance sheet of ALX Oncology Holdings Inc. as of April 1, 2020 (inception), and the related notes, in the registration statement (No. 333-251171) on Form S-1, included therein and incorporated by reference herein, and to the reference to our firm under the heading “Experts”.

Exhibit 23.2

Consent of Independent Registered Public Accounting Firm

The Board of Directors

ALX Oncology Limited:

We consent to the use of our report dated May 5, 2020, except for the retroactive effect of the reverse stock split as described under the heading ‘Reverse Stock Split’ in Note 13, which is as of July 13, 2020, with respect to the consolidated balance sheets of ALX Oncology Limited and subsidiaries as of December 31, 2018 and 2019, the related consolidated statements of operations and comprehensive loss, convertible preferred shares and shareholders’ deficit, and cash flows for each of the years in the two-year period ended December 31, 2019, and the related notes, in the registration statement (No. 333-251171) on Form S-1, included therein and incorporated by reference herein, and to the reference to our firm under the heading “Experts”.