Aptose Biosciences : Corporate Presentation January 2023

Aptose Corporate Presentation January 2023

I n c o r p o r a t i n g c l i n i c a l d a t a f r o m 2 0 2 2 A S H A n n u a l M e e t i n g

P R E C I S I O N O N C O L O G Y F O R

T H E R A P I E S O F T O M O R R O W

NASDAQ: APTO TSX: APS

Disclosure

This presentation does not, and is not intended to, constitute or form part of, and should not be construed as, an offer or invitation for the sale or purchase of, or a solicitation of an offer to purchase, subscribe for or otherwise acquire, any securities, businesses and/or assets of any entity, nor shall it or any part of it be relied upon in connection with or act as any inducement to enter into any contract or commitment or investment decision whatsoever.

This presentation contains forward-lookingstatements, which reflect APTOSE Biosciences Inc.'s (the "Company") current expectations, estimates and projections regarding future events, including statements relating to our business strategy, our clinical development plans, our ability to obtain the substantial capital we require, our plans to secure strategic partnerships and to build our pipeline, our clinical trials and their projected timeline, the efficacy and toxicity of our product candidates, potential new intellectual

property, our plans, objectives, expectations and intentions; and other statements including words such as "anticipate", "contemplate", "continue", "believe", "plan", "estimate", "expect", "intend", "will", "should", "may", and other similar expressions. Such statements constitute forward-looking statements within the meaning of securities laws.

Although the Company believes that the views reflected in these forward-looking statements are reasonable, such statements involve significant risks and uncertainties, and undue reliance should not be placed on such statements. Certain material factors or assumptions are applied in making these forward-looking statements, and actual results may differ materially from those statements. Those factors and risks include, but are not limited to, our ability to raise the funds necessary to continue our operations, changing market conditions, the successful and timely completion of our clinical studies including delays, the demonstration of safety and efficacy of our drug candidates, our ability to recruit patients, the establishment and maintenance of corporate alliances, the market potential of our product candidates, the impact of competitive products and pricing, new product development, changes in laws and regulations, uncertainties related to the regulatory approval process and other risks detailed from time to time in the Company's ongoing quarterly filings and annual reports.

Forward-looking statements contained in this document represent views only as of the date hereof and are presented for the purpose of assisting potential investors

in understanding the Company's business and may not be appropriate for other purposes. The Company does not undertake to update any forward-looking statements, whether written or oral, that may be made from time to time by or on its behalf, except as required under applicable securities legislation. Investors should read

the Company's continuous disclosure documents available at www.sedar.comand EDGAR at www.sec.gov/edgar.shtml,especially the risk factors detailed therein.

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Precision Oncology Company Developing Oral Kinase Inhibitors to Treat Life-threatening Hematologic Malignancies

Tuspetinib │ Safely Treats AML Disease Heterogeneity │ Orphan Drug Status │ Fast Track Status

Disease heterogeneity is the greatest obstacle to the effective treatment of AML

• Caused by malleable and adaptable patchwork of adverse mutations and altered gene expression
• Renders patients unresponsive to current therapies, leading to diverse populations of R/R AML
• Suppressing a single target insufficient to disrupt redundant and adaptable signaling pathways

Tuspetinib is a Safe and Effective, Once Daily, Oral Drug to Treat AML Disease Heterogeneity

Best-in-Class TKI simultaneously targets clinically-validated oncogenic signaling kinases: SYK│JAK1/2│FLT3WT/MUT│cKITMUT

Non-myelosuppressive, favorable safety profile	Drug of choice for combination therapy
No drug-related SAE, QTC prolongation, differentiation syndrome	Safety and breadth of efficacy position for doublet & triplet therapy
Broad application across diverse AML populations	Accelerated paths to market as monotherapy
NPM1-mutant │ MLL-mutant | RAS-mutant │ TP53-mutant │ FLT3-mutant	Potential to treat R/R AML of high unmet need │ Prior FLT3i Failure

Single agent CRs across 4 dose levels with no DLT	$1B market potential & broad IP coverage
Once daily oral tablet │40 mg │ 80 mg │ 120 mg │ 160 mg	Potential to become preferred agent for multiple applications

Expect near term value creation as monotherapy in deep R/R AML populations of high unmet need

Expect long term value creation as ideal TKI for doublet/triplet combination therapy in 1L/2L AML

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Tuspetinib Treats AML Disease Heterogeneity

Why We Believe Tuspetinib Can Address the Greatest Needs of

AML Patients and Achieve ≥ $1B Commercial Success

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Tuspetinib Targets Clinically Validated Kinases in Oncogenic Signaling Pathways

C-KITMUT

Excessive levels of FLT3 ligand bind to FLT3 Receptor (WT & Mutated)

SYK

JAK

	STAT			Ras
	NPM1cMUT
				RAF
				MEK
Direct		BTK Pwy
Inhibition			ERK
				RSK
			NFkB	MAPK / ERK
			pathway

PI3K

AKT

mTOR

S6K

PI3K / AKT / mTOR / S6K pathway

Growth Factor

Receptors

JAK

SYK

STAT

JNK

Pwy

Potent suppression of multiple kinases operative in AML

All forms of FLT3

SYK signal transduction kinase

JAK 1/2 signal transduction kinases

cKITMUT alternative receptor kinases RSK in RAS pathway

• Multi-drugtherapy in a single tablet
• Simultaneously suppresses multiple dysregulated signal transduction pathways that drive AML proliferation and resistance mechanisms
• Ideal for MONOTHERAPY and COMBINATION therapy

Cell Growth and Proliferation

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