---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-26-004119"
form_type: "8-K"
ticker: "APTOF"
cik: "0000882361"
company_name: "Aptose Biosciences Inc."
filed_at: "2026-06-15T12:00:25+00:00"
generated_at: "2026-06-15T12:07:47.899005+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Aptose TUSCANY trial shows 86.2% CRc in newly diagnosed AML; all TP53-mut respond

## Summary
- Composite complete response (CRc) rate 86.2% in evaluable patients across all TUS+VEN+AZA dose groups.
- MRD negativity rate 86.4% in patients achieving CR/CRh; 62.5% overall MRD negative among all dosed.
- 160mg cohort: 100% CR in 4 TP53-mutated patients with complex karyotype; 76.9% CRc across 13 patients.
- No treatment-related deaths, QT prolongation, CPK elevations, or differentiation syndrome observed.
- 19 patients remain on treatment; 6 proceeded to stem cell transplantation.

## SEC filing metadata
- accession: 0001171843-26-004119
- form_type: 8-K
- ticker: APTOF
- cik: 0000882361
- company_name: Aptose Biosciences Inc.
- filed_at: 2026-06-15T12:00:25+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/882361/000117184326004119/0001171843-26-004119-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/882361/000117184326004119/f8k_061326.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-26-004119
- JSON: https://secwatch.observer/filing/0001171843-26-004119.json
- Plain text: https://secwatch.observer/filing/0001171843-26-004119.txt

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