Ms. Susan Pietropaolo reports

APTOSE ANNOUNCES CLOSING OF $9.7 MILLION PUBLIC OFFERING AND CONCURRENT $4 MILLION PRIVATE PLACEMENT WITH HANMI PHARMACEUTICAL, INCLUDING FULL EXERCISE OF OVER-ALLOTMENT OPTION

Aptose Biosciences Inc. has closed the previously announced public offering of 5,649,122 common shares of the company and warrants at a combined offering price of $1.71 (U.S.) per share. This includes 736,842 common shares and warrants pursuant to a full exercise by the underwriter of its overallotment option. Each common share was sold with a warrant to purchase a common share at an exercise price of $1.71 (U.S.) per warrant share.

Aptose also announced the closing of the previously announced $4-million (U.S.) private placement of common shares with Hanmi Pharmaceutical Inc., Seoul, South Korea, yielding ownership of 19.03 per cent of the outstanding common shares of the company. Under the terms of the strategic investment, Hanmi purchased each common share at a price of $1.90 (U.S.), representing an 11-per-cent premium over the price of the common shares issued as part of the public offering. The company also issued Hanmi warrants to purchase common shares at an exercise price of $1.71 (U.S.) per warrant share.

Total gross proceeds from the public offering and private placement were approximately $13.7-million, excluding underwriting discounts, placement agent commissions and other offering-related expenses. The total number of common shares outstanding after the closing of the public offering, including the overallotment option, and private placement is 15,706,810 and warrants outstanding are 8,332,163.

Aptose intends to use the net proceeds of the public offering and private placement to (i) support clinical trials for tuspetinib; (ii) support manufacture of tuspetinib clinical supplies; and (iii) for working capital and general corporate purposes.

Newbridge Securities Corp. acted as the sole book-running manager for the public offering and as placement agent for the private placement.

No common shares or warrants have been offered or sold in Canada as part of the public offering or private placement. The public offering and private placement have been subject to the approval of the Toronto Stock Exchange and Nasdaq. For the purposes of TSX approval, the company is relying on the exemption set forth in Section 602.1 of the TSX company manual, which provides that the TSX will not apply its standards to certain transactions involving eligible interlisted issuers on a recognized exchange, such as Nasdaq.

The securities sold in the public offering were offered by Aptose pursuant to a registration statement on Form S-1 (file No. 333-275870), including a base prospectus, that was previously filed by Aptose with the Securities and Exchange Commission (SEC) and was declared effective on Jan. 25, 2024. The public offering was made only by means of a written prospectus and prospectus supplement that form a part of the registration statement. Before you invest, you should read the prospectus supplement and the accompanying prospectus and other documents the company has filed with the SEC for more complete information about the company and the public offering. You may get these documents for free by visiting EDGAR on the SEC website. Alternatively, copies of the final prospectus supplement may be obtained by contacting Newbridge Securities, attention: equity syndicate department, 1200 North Federal Highway, suite 400, Boca Raton, Fla., 33432, by e-mail at syndicate@newbridgesecurities.com or by telephone at 877-447-9625. The securities to be sold to Hanmi have not been registered under the U.S. Securities Act of 1933, as amended, and will be issued in reliance on an exemption from the registration requirements thereof.

About Aptose Biosciences Inc.

Aptose Biosciences is a clinical-stage biotechnology company 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 product, tuspetinib, is a once-daily oral therapy being studied as monotherapy and in combination therapy in the Aptivate international phase 1/2 expansion trial in patients with relapsed or refractory acute myeloid leukemia (AML).

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