Dr. William Rice reports

APTOSE AND HANMI PHARMACEUTICAL EXTEND LOAN AGREEMENT TO CONTINUE DEVELOPMENT OF TUSPETINIB IN TRIPLET THERAPY FOR AML

Aptose Biosciences Inc. has entered into an $11.9-million (U.S.) amended loan facility agreement with Hanmi Pharmaceutical Co. Ltd.

The facility agreement is uncommitted and administered through multiple advances until Dec. 31, 2025, and will be used to finance Aptose's business and clinical operations expenses reasonably related to the advancement of tuspetinib. Aptose has not yet received funds from this facility agreement but expects the first advance soon. This facility agreement has been amended and restated from the prior June, 2025, facility agreement between Hanmi and Aptose. No single advance shall be for an amount in excess of $2-million (U.S.), and any unpaid principal amount with respect to each advance shall accrue interest at 6 per cent per annum. The facility agreement contains customary affirmative and negative covenants and securities that are subject to a number of limitations and exceptions.

In addition, Aptose has received the final advance of $1.4-million (U.S.) for a total of $8.5-million (U.S.) from the prior June, 2025, facility agreement with Hanmi.

"The growing body of positive data on tuspetinib demonstrates that, by adding TUS to the VEN+AZA standard of care in AML, we can safely and more effectively treat some of AML's largest patient populations, in addition to subgroups having adverse genetics defined by FLT3, NKRAS and TP53 genes," said Dr. William G. Rice, PhD, chairman, president and chief executive officer of Aptose. "We are very grateful for Hanmi's support for the continued development of an important new treatment in the AML armamentarium."

Tuspetinib is a convenient once-daily oral agent that potently targets SYK, mutated and wild type forms of FLT3, mutated KIT, JAK1/2, and RSK2 kinases, while avoiding many typical toxicity concerns observed with other agents. The continuing Tuscany triplet phase 1/2 study is designed to test various doses and schedules of TUS in combination with standard dosing of azacitidine and venetoclax in newly diagnosed patients with AML who are ineligible to receive induction chemotherapy. Aptose recently reported data from the first three dose cohorts that have demonstrated safety, CRs and minimal residual disease negativity across patients with diverse mutations. The early data showed that nine out of 10 patients responded to the TUS triplet therapy, with 100-per-cent complete remission achieved in the 80-milligram and 120-milligram cohorts. Notably, patients with difficult-to-treat mutations in TP53, RAS and FLT3 genes also achieved a 100-per-cent CR/CRh rate.

The September, 2025, loan facility agreement constitutes a related-party transaction within the meaning of Multilateral Instrument 61-101 (Protection of Minority Security Holders in Special Transactions) as Hanmi is a related party of the company under Canadian securities laws. However, the company is relying on the exemption from the formal valuation and minority shareholder approval requirements contained in MI 61-101 on the basis of the financial hardship exemption therein. In its consideration and approval of the September, 2025, loan facility agreement, the board of directors of the company, acting in good faith and having taken into account the liquidity, financial position and cash needs of the company, the alternatives available to the company, relevant benefits, risks, and other factors, including the relative impacts on applicable stakeholders, and such matters they considered relevant or appropriate, unanimously determined that entering into the September, 2025, loan facility agreement will result in an improvement of the company's financial position, and that the terms of the September, 2025, loan facility agreement are reasonable in the circumstances of Aptose. The company did not file a material change report 21 days prior to the execution of the September, 2025, loan facility agreement as details of the September, 2025, loan agreement were unknown at such time.

About Aptose Biosciences Inc.

Aptose Biosciences is a clinical-stage biotechnology company committed to developing precision medicines 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's lead clinical-stage compound tuspetinib is an oral kinase inhibitor that has demonstrated activity as a monotherapy and in combination therapy in patients with relapsed or refractory acute myeloid leukemia, and is being developed as a front line triplet therapy in newly diagnosed AML.

We seek Safe Harbor.