Proposed plan of arrangement

On November 18, 2025, the Company entered into a definitive arrangement agreement (the “Arrangement Agreement”) with Hanmi and HS North America Ltd., a wholly owned subsidiary of Hanmi (“Hanmi Purchaser” and together with Hanmi, the "Hanmi Purchasers") pursuant to a plan of arrangement of the Company under the Canada Business Corporations Act (the "Arrangement") whereby Hanmi Purchaser will acquire all of the issued and outstanding Common Shares of the Company that are not currently owned or controlled by the Hanmi Purchasers or their respective affiliates. Pursuant to the Arrangement, each shareholder of the Company will receive an amount in cash equal to C$2.41 for each Common Share of the Company held by such shareholder. All incentive securities and warrants of the Company, whether vested or unvested, outstanding on the effective date of the Arrangement shall be deemed (i) cancelled and/or (ii) surrendered and cancelled, and each holder of options, restricted stock units or warrants shall cease to be a holder of such options, restricted stock units or warrants. Following the completion of the Arrangement, the Company’s securities will be delisted from the Toronto Stock Exchange.

On February 23, 2026, the Arrangement Agreement was amended and restated to among other things, extend the outside date for completing the Arrangement from March 15, 2026 to June 30, 2026. On March 31, 2026, shareholders of the Company approved the Arrangement at a special meeting of shareholders held for such purpose. In connection with the Arrangement, the Company will continue from the Canada Business Corporations Act to the Business Corporations Act (Alberta). The Arrangement is expected to close in the first half of 2026, subject to the satisfaction of customary closing conditions (see Note 18).

Transactions with Hanmi Pharmaceutical Co. Ltd.

On November 4, 2021, Aptose entered into a licensing agreement (the "Tuspetinib Licensing Agreement") with the South Korean company Hanmi for the clinical and commercial development of tuspetinib. Under the terms of the Tuspetinib Licensing Agreement, Hanmi granted Aptose exclusive worldwide rights to tuspetinib for all indications.

Hanmi received an upfront payment of $12.5 million, including $5.0 million in cash and $7.5 million in Common Shares. Aptose issued Hanmi 7,190 Common Shares as part of the upfront licensing payment. Hanmi will also receive up to $407.5 million in future milestone payments contingent upon achieving certain clinical, regulatory and sales milestones across several potential indications, as well as tiered royalties on net sales. The term of the Tuspetinib Licensing Agreement will continue on a product-by-product and country-by-country basis until the expiration of the royalty period for such product in such country. The licenses to Aptose pursuant to the Tuspetinib Licensing Agreement will survive and become non-exclusive, perpetual, irrevocable and fully paid-up on a product-by-product and country-by-country basis, upon their natural expiration under the terms of the Tuspetinib Licensing Agreement.

In 2022, the Company and Hanmi also entered into a separate supply agreement for additional production of new drug substance and drug product to support further tuspetinib clinical development (the “Supply Agreement”), for which the Company pays Hanmi per batch of production. For the years ended December 31, 2025 and 2024, expenses related to the Supply Agreement totaled nil for both periods. Since inception to December 31, 2025, $7.1 million has been expended under the Supply Agreement.

Under the Supply Agreement, the Company paid supply costs to Hanmi of nil and $2.6 million for the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025 and 2024, the Company did not have either accounts payable or accrued liabilities related to the Supply Agreement.

On August 27, 2024, the Company and Hanmi entered into the Hanmi Loan Agreement, pursuant to which Hanmi loaned $10.0 million to the Company. Under the terms of the Hanmi Loan Agreement, the loan proceeds are restricted to use for tuspetinib-related business operation purposes, unless otherwise authorized by Hanmi. The use of the funds is also contingent upon the Company meeting specific manufacturing and clinical milestones as outlined in the agreement. The loan is repayable in full on January 31, 2027, with an initial interest period ending on September 30, 2024 and subsequent interest payments due at the end of each three-month period thereafter. Aptose may repay all or any portion of the outstanding principal at any time without penalty, provided that any accrued and unpaid interest on the principal amount being repaid is also settled. The accrued interest on the unpaid principal loan amount is payable at the periods specified in the Hanmi Loan Agreement at a rate of 6% per annum.

On March 18, 2025, the Company entered into a debt conversion and interest payment agreement ("Debt Conversion Agreement") with Hanmi pursuant to which the Company and Hanmi agreed to convert $1.5 million of Hanmi's indebtedness under the Hanmi Loan Agreement into 409,063 Common Shares at $3.70 per share, which was the average closing price of the Company's Common Shares on Nasdaq for the five trading days immediately prior to entering into the Debt Conversion Agreement. Additionally, pursuant to the Debt Conversion Agreement, the Company and Hanmi agreed that the interest payment associated with the period from December 21, 2024 through March 31, 2025 (the "First Deferred Interest Period") may be deferred and made on or before the final closing date of a financing, not including the amount being converted pursuant to the Debt Conversion Agreement, totaling $15.0 million ("Capital Raise"), but no later than June 27, 2025. On June 24, 2025, the Company and Hanmi entered into an interest payment agreement whereby the interest due for the First Deferred Interest Period and interest associated with the period from March 31, 2025 through June 30, 2025 (the "Second Deferred Interest Period") may be deferred and made no later than December 31, 2025. Further, pursuant to the Debt Conversion Agreement, Hanmi, at its sole discretion, can opt to convert the remaining indebtedness amount, or a portion thereof, to Aptose Common Shares upon the successful completion of the Capital Raise, provided that the amount of Aptose Common Shares delivered to Hanmi pursuant to such subsequent conversion shall not cause Hanmi to own more than 19.99% of the Company. Subsequently, pursuant to the Hanmi Facility Agreement, the maturity date for the Hanmi Loan Agreement was modified such that the outstanding principal amount and accrued and unpaid interest under the Hanmi Loan Agreement would be repayable on August 31, 2028 as discussed below.

Pursuant to FASB’s ASC Topic 470, Debt (“ASC 470”), the Company accounted for the debt conversion as a troubled debt restructuring as the Company was experiencing financial difficulties and a concession had been granted whereby by the effective interest rate of the modified debt was lower than the original interest rate pursuant to the Hanmi Loan Agreement. The carrying value of the loan was reduced by the fair value of the Common Shares issued in connection with the transaction. The Company determined that the future undiscounted cash flows of the loan exceeded its carrying value, and accordingly, no gain was recognized in connection with the Debt Conversion Agreement.

On June 18, 2025, the Company and Hanmi entered into the Hanmi Facility Agreement, pursuant to which Hanmi provided an uncommitted facility ("Facility #1") for up to $8.5 million, administered through multiple advances for the purpose of the continued clinical development of tuspetinib and to fund operations of the Company. Advances under the Hanmi Facility Agreement may be provided in one or more (but no more than five advances) until December 31, 2025. No single advance shall be for an amount in excess of $2.5 million. Any amounts repaid under the Hanmi Facility Agreement may not be re-borrowed. As of December 31, 2025, the Company fully utilized this facility and received a total of $8.5 million under the Hanmi Facility Agreement. Amounts outstanding pursuant to the Hanmi Facility Agreement are repayable in full on August 31, 2028, with an initial interest period commencing on June 20, 2025 and ending on December 31, 2025 and subsequent interest periods calculated based on each three-month period thereafter. Unpaid principal with respect to each advance shall accrue interest at a rate of 6% per annum.

Pursuant to the Hanmi Facility Agreement, the maturity date for the Hanmi Loan Agreement was modified such that the outstanding principal amount and accrued and unpaid interest under the Hanmi Loan Agreement would be repayable on August 31, 2028. The Company evaluated whether the amended maturity date represented a debt modification or extinguishment in accordance with ASC 470-50, Debt – Modifications and Extinguishments. The amendment to the Hanmi Loan Agreement was accounted for as a debt modification since the amendment did not result in substantially different terms as the present value of the cash flows pursuant to the revised terms is less than 10% different from the remaining cash flows under the terms of the original agreement.

On September 22, 2025, the Company and Hanmi entered into the Amended Facility Agreement, pursuant to which Hanmi provided an additional uncommitted facility ("Facility #2") for up to $11.9 million, administered through multiple advances for the purpose of the continued clinical development of tuspetinib and to fund operations of the Company. Advances under the Amended Facility Agreement may be provided in one or more (but no more than eight advances) until December 31, 2025, subsequently extended to January 31, 2026 (see Note 18). No single advance shall be for an amount in excess of $2.0 million or for an amount that is less than $0.5 million. Additionally, Hanmi may cancel availability under the Amended Facility Agreement at any time without notice, acting solely at its discretion. Any amounts repaid under the Amended Facility Agreement may not be re-borrowed. As of December 31, 2025, Aptose received a total of $10.0 million under the Amended Facility Agreement with the remaining available amount of $1.9 million received in January 2026 (see Note 18). Amounts outstanding pursuant to the Amended Facility Agreement are repayable in full on August 31, 2028, with an initial interest period commencing on September 22, 2025 and ending on December 31, 2025 and subsequent interest periods calculated based on each three-month period thereafter. Unpaid principal with respect to each advance shall accrue interest at a rate of 6% per annum.

Pursuant to the Amended Facility Agreement, the Amended Facility Agreement effectively replaced the Hanmi Facility Agreement. The Company evaluated whether the Facility #2 transaction resulted in a debt modification or extinguishment to Facility #1 in accordance with ASC 470-50, Debt – Modifications and Extinguishments. The amendment to Facility #1 was accounted for as a debt modification since the amendment did not result in substantially different terms as the present value of the cash flows pursuant to the revised terms is less than 10% different from the remaining cash flows under the terms of the original agreement.

During the years ended December 31, 2025 and 2024, Aptose recognized interest expense of $0.8 million and $0.2 million, respectively, and paid nil and $0.2 million, respectively, in interest pursuant to the Hanmi Loan Agreement, Hanmi Facility Agreement and Amended Facility Agreement. As of December 31, 2025 and 2024, accrued interest on the related party loan payable was $0.9 million and $18,000, respectively, with such amounts classified as a long-term liability given unpaid interest is due on August 31, 2028.

Pursuant to the Hanmi Facility Agreement and Amended Facility Agreement, the Company granted a first ranking general security interest to Hanmi over all present and after acquired personal property, including over all inventory of drug substances and drug products that the Company has purchased or manufactured or will purchase or manufacture, and the Tuspetinib Licensing Agreement and all tuspetinib clinical trial data.

In connection with the Hanmi Loan Agreement, on September 2, 2024, Aptose and Hanmi executed a letter of understanding, which outlines the steps associated with the negotiation of a co-development collaboration agreement for the advancement of tuspetinib (the "Future Collaboration Agreement"). Under the terms of the Future Collaboration Agreement, upon execution, the loan principal and any accrued and unpaid interest under the Hanmi Loan Agreement will automatically convert to Hanmi's prepayment of future milestone obligations under the Future Collaboration Agreement. Upon conversion, the Hanmi Loan Agreement, consisting of the $10.0 million loan principal with any accrued and unpaid interest, would be deemed fully paid and satisfied. Hanmi has a security interest over all inventory of drug substance and drug products related to the Tuspetinib License Agreement.

As of December 31, 2025, Hanmi held 508,710 Common Shares and 77,972 warrants to purchase Common Shares at an exchange price of $51.30 per Common Share of Aptose. See also Note 13: Share capital.

Short-term advance from CEO

On June 17, 2025, the Company's CEO provided an interest-free short-term advance of $100,000 to support operations. The amount was repaid in full on June 26, 2025. The loan balance was not outstanding at December 31, 2025.