---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-25-007795"
form_type: "8-K"
ticker: "APTOF"
cik: "0000882361"
company_name: "Aptose Biosciences Inc."
filed_at: "2025-12-08T23:59:59+00:00"
generated_at: "2026-05-16T14:09:30.996805+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Aptose presents tuspetinib triplet therapy data at ASH: 100% CR/CRh at higher doses in AML

## Summary
- 90% CR/CRh across all doses (40/80/120 mg TUS); 100% at 80 mg and 120 mg levels.
- 78% of responders achieved MRD negativity by central flow cytometry.
- No dose-limiting toxicities or drug-related deaths; febrile neutropenia in 2 subjects (16.7%).
- Responses seen in FLT3-WT, TP53/complex karyotype, RAS, and MDS-related mutations.
- Preliminary data at 160 mg cohort show early blast clearance and MRD negativity.

## SEC filing metadata
- accession: 0001171843-25-007795
- form_type: 8-K
- ticker: APTOF
- cik: 0000882361
- company_name: Aptose Biosciences Inc.
- filed_at: 2025-12-08T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/882361/000117184325007795/0001171843-25-007795-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/882361/000117184325007795/f8k_120525.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-25-007795
- JSON: https://secwatch.observer/filing/0001171843-25-007795.json
- Plain text: https://secwatch.observer/filing/0001171843-25-007795.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.