UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 10-K/A

(AMENDMENT NO. 3)

(Mark one)

For the fiscal year ended December 31, 2018.

Commission file number 001-3200

APTOSE BIOSCIENCES INC.

(Exact name of registrant as specified in its charter)

251 Consumers Road, Suite 1105

Toronto, Ontario, Canada M2J 4R3

(Address of principal executive offices)

647-479-9828

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Common Shares, without par value                  The Nasdaq Stock Market

Securities registered pursuant to Section 12(g) of the Act:
None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YES ☐ NO ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. YES ☐ NO ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. YES ☒ NO ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§229.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). YES ☒ NO ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10 K or any amendment to this Form 10 K. ☒

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 definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

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 13(a) of the Exchange Act. ☒

Indicate by check mark whether registrant is a shell company (as defined in Rule 12b 2 of the Act). YES ☐ NO ☒

The aggregate market value of the voting stock and nonvoting common equity held by non-affiliates computed by reference to the price at which the common equity was last sold, or the average bid and asked prices of such common equity, as of June 30, 2018 was $134,370,583.00.

As of March 12, 2019, the registrant had 41,499,112 shares of common stock outstanding.

EXPLANATORY NOTE

This Amendment No. 3 to Form 10-K (this “Amendment No. 3”) amends the Annual Report on Form 10-K of Aptose Biosciences Inc. (the “Company”) for the year ended December 31, 2018, which was originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 12, 2019 (the “Original 10-K”) and amended on March 26, 2019 and April 12, 2019. This Amendment No. 3 is being filed solely for the purpose of replacing Exhibit 10.10 and Exhibit 10.15 from the Original 10-K with a new Exhibit 10.10 and Exhibit 10.15 in connection with the SEC’s new rules and procedures for exhibits containing immaterial, competitively harmful information and the Company’s withdrawal of its confidential treatment request pertaining to the same exhibits. In addition, as required by Rule 12b-15 under the Securities Exchange Act of 1934, new certifications by our principal executive officer and principal financial officer are filed as exhibits to this Amendment No. 3. However, because no financial statements are contained within this Amendment No. 3, we are not including new certifications pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

Except as specifically provided otherwise herein, this Amendment No. 3 does not reflect events occurring after March 12, 2019, the date of the filing of our Original 10-K, or modify or update those disclosures that may have been affected by subsequent events. Accordingly, this Amendment No. 3 should be read in conjunction with the Original 10-K.

PART IV.

ITEM 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES

(a) Documents filed as part of this report.

1. Financial Statements. Consolidated Financial Statements are included in our Original 10-K immediately following the signature page of the report.

2. Financial Statement Schedules.

All schedules were omitted because they were not applicable or the required information was shown in the Consolidated Financial Statements or notes thereto filed with our Original 10-K.

3. Exhibits.

See note below under (b).

(b) Exhibits

The exhibits listed in Part IV, Item 15. “Exhibits, Financial Statement Schedules” of the Original 10-K were filed or incorporated by reference as part of the Original 10-K and Exhibit 10.10 and Exhibit 10.15 listed in the Exhibit Index below are filed herewith as part of this Amendment No. 3 to replace Exhibit 10.10 and Exhibit 10.15 of the Original 10-K.

* Filed herewith.

^ Portions of this exhibit have been omitted pursuant to Rule 601(b)(10) of Regulation S-K.

SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Diego, State of California, on the 22nd day of April, 2019.

Aptose Biosciences Inc.

By: /s/ William G. Rice                            

William G. Rice

Chairman, Chief Executive Officer and President