Aptose to Report First Quarter 2021 Financial Results and Hold Conference Call on Tuesday, May 4, 2021  

SAN DIEGO and TORONTO, April 26, 2021 (GLOBE NEWSWIRE) — Aptose Biosciences Inc. (Nasdaq: APTO; TSX: APS), a clinical stage company developing highly differentiated therapeutics that target the underlying mechanisms of cancer, will report financial results for the quarter ended March 31, 2021, and provide a corporate update on Tuesday, May 4, 2021, after the close of the market. Conference Call & Webcast: Date:Tuesday, May 4, 2021Time:4:30 PM ETDial In – Toll-Free:1 844-882-7834Dial In – International:1 574-990-9707Conference ID:2788133Webcast:https://edge.media-server.com/mmc/p/bnrjs6pf  Replay available through May 11, 2020:  Dial In – Toll-Free:1 855-859-2056Dial In – International:1 404-537-3406Conference ID:2788133 The live conference call can also be accessed through a link on the Investor Relations section of Aptose’s website at https://www.aptose.com/investors/news-events/ir-calendar. An archived version of the webcast along with a transcript will be available on the company’s website for 30 days.  The press release, the financial statements and the management’s discussion and analysis for the year and quarter ended March 31, 2021 will be available on SEDAR at www.sedar.com and EDGAR at www.sec.gov/edgar.shtml. About Aptose Aptose Biosciences is a clinical-stage biotechnology company committed to developing personalized therapies addressing unmet medical needs in oncology, with an initial focus on hematology. The Company’s small molecule cancer therapeutics pipeline includes products designed to provide single agent efficacy and to enhance the efficacy of other anti-cancer therapies and regimens without overlapping toxicities. The Company has two clinical- stage investigational products for hematologic malignancies: luxeptinib (formerly CG-806), an oral, first-in-class mutation-agnostic FLT3/BTK kinase inhibitor, is in a Phase 1a/b trial in patients with relapsed or refractory B cell malignancies, including chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL) and non-Hodgkin lymphoma (NHL), who have failed or are intolerant to standard therapies, and is in a separate Phase 1a/b trial in patients with relapsed or refractory acute myeloid leukemia (AML); APTO-253, the only clinical-stage agent that directly targets the MYC oncogene and suppresses its expression, is in a Phase 1a/b clinical trial for the treatment of patients with relapsed or refractory AML or high risk myelodysplastic syndrome (MDS). For further information, please contact: Aptose Biosciences Inc.LifeSci Advisors, LLCSusan PietropaoloDan Ferry, Managing DirectorInvestor Relations617-535-7746201-923-2049Daniel@[email protected]