Hanmi Pharmaceutical Co. Ltd.

On November 4, 2021, Aptose entered 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 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 three months ended March 31, 2025 and 2024, expenses related to the Supply Agreement totaled nil for both periods. Since inception to March 31, 2025, $7.1 million had 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 three months ended March 31, 2025 and 2024, respectively. At March 31, 2025 and December 31, 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. During the three months ended March 31, 2025, Aptose recognized interest expense of $0.1 million and paid nil in interest pursuant to the Hanmi Loan Agreement.

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 may be deferred and made on or before the final closing date of a financing, not including the amount being

Pursuant to FASB’s Accounting Standards Codification (“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 their carrying value, and accordingly, no gain or loss was recognized in connection with the Debt Conversion Agreement.

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 $8.5 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 March 31, 2025, Hanmi held 508,710 Common Shares and 77,972 warrants to purchase Common Shares at at exercise price of $51.30 per Common Share of Aptose. Also see Note 11, Share capital.