Business Description

— Cautionary Note Regarding Forward-Looking Statements.” As used in this report, the terms “Aptose,” “Aptose Biosciences,” the “Company,” "the "Corporation," “we,” “us,” “our” and similar references refer to Aptose Biosciences Inc. (formerly known as Lorus Therapeutics Inc.) and our consolidated subsidiaries, and the term “Common Shares” refers to our common shares, no par value. Aptose had historically qualified as a “foreign private issuer” for purposes of reporting under the Exchange Act, and filing registration statements under the Securities Act of 1933, as amended. Effective December 31, 2018, however, Aptose ceased qualifying as a foreign private issuer and began filing reports with the United States Securities and Exchange Commission ("SEC") as a “domestic issuer.” As a result, Aptose changed the accounting standards by which it prepares its financial statements from International Financial Reporting Standards to generally accepted accounting principles in the United States, or “U.S. GAAP.” All financial statements contained in this Annual Report are presented in accordance with U.S. GAAP. This report contains the following trademark, trade name and service mark of ours: Aptose. This report also contains