Aptose Biosciences (APTO) Corporate presentation summary

Market opportunity and medical need

• Acute myeloid leukemia (AML) is highly aggressive with poor survival rates, especially in patients over 65 years old.

• Current standard of care (VEN + AZA) yields limited responses and short median overall survival (<15 months), with drug resistance emerging.

• There is a critical need for improved frontline therapies that achieve deeper, more durable responses and extend survival.

• Adding a third agent to VEN + AZA is expected to boost effectiveness, provided it is safe, broadly active, and avoids resistance.

• Tuspetinib (TUS) is positioned as an ideal third agent due to its efficacy, safety, and broad activity across AML subgroups.

Tuspetinib clinical profile and mechanism

• TUS is an oral targeted agent that inhibits key oncogenic kinases, including FLT3, SYK, and JAK, while avoiding targets that compromise safety.

• Demonstrates suppression of oncogenic signaling and promotes cancer cell death, directly targeting mechanisms of VEN resistance.

• TUS has shown broad-spectrum activity in both FLT3-mutated and wildtype AML, including patients who failed prior therapies.

• Favorable safety profile with no drug-related myelosuppression, QTc prolongation, or differentiation syndrome observed in trials.

• TUS + VEN doublet and TUS single agent studies show activity in high-risk and heavily pretreated relapsed/refractory AML populations.

Competitive landscape and differentiation

• Gilteritinib triplet therapy boosts CR rates but is limited to FLT3-mutated patients and adds toxicities requiring dose reductions.

• TUS offers broader activity, including in FLT3 wildtype patients (70% of AML), and is better tolerated than Gilteritinib.

• TUS achieves responses in patients who failed Gilteritinib and at lower, better-tolerated doses.

• TUS may avoid resistance to VEN and is effective in animal models with VEN and HMA.