---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-25-000957"
form_type: "8-K"
ticker: "APTOF"
cik: "0000882361"
company_name: "Aptose Biosciences Inc."
filed_at: "2025-02-20T23:59:59+00:00"
generated_at: "2026-05-26T09:59:52.435345+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Aptose gets CSRC approval to escalate TUS dose; CRs seen in difficult AML

## Summary
- CSRC unanimously approves dose escalation from 40 mg to 80 mg of tuspetinib in TUSCANY trial of TUS+VEN+AZA triplet.
- Four patients dosed at 40 mg; no DLTs or prolonged myelosuppression; all remain on study.
- Two FLT3-WT patients achieved CR/CRh; one patient with biallelic TP53 mutations and complex karyotype achieved CR.
- Enrollment open for 80 mg cohort; 18-24 patients expected by mid-late 2025.
- PK shows TUS plasma levels unaffected by AZA; VEN levels consistent with prior studies.

## SEC filing metadata
- accession: 0001171843-25-000957
- form_type: 8-K
- ticker: APTOF
- cik: 0000882361
- company_name: Aptose Biosciences Inc.
- filed_at: 2025-02-20T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/882361/000117184325000957/0001171843-25-000957-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/882361/000117184325000957/f8k_022025.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-25-000957
- JSON: https://secwatch.observer/filing/0001171843-25-000957.json
- Plain text: https://secwatch.observer/filing/0001171843-25-000957.txt

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