---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-23-003043"
form_type: "8-K"
ticker: "APTOF"
cik: "0000882361"
company_name: "Aptose Biosciences Inc."
filed_at: "2023-05-08T23:59:59+00:00"
generated_at: "2026-06-15T15:15:02.751346+00:00"
event_type: "earnings"
sentiment: "negative"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Aptose Q1 net loss widens to $13.7M; tuspetinib doublet dosing underway

## Summary
- Net loss $13.7M ($0.15/sh) vs $11.5M ($0.12) YoY; R&D spend up to $8.8M.
- Cash and investments $35.7M; runway through March 2024.
- Tuspetinib APTIVATE trial: dose escalation/exploration complete; doublet with venetoclax dosing initiated with early blast reductions.
- Safety review: no drug-induced myelosuppression or DLTs up to 160mg/day in >70 patients.
- Anticipated FDA EOP1 meeting in Q2 2023 and clinical data presentation at EHA June 2023.

## SEC filing metadata
- accession: 0001171843-23-003043
- form_type: 8-K
- ticker: APTOF
- cik: 0000882361
- company_name: Aptose Biosciences Inc.
- filed_at: 2023-05-08T23:59:59+00:00
- event_type: earnings
- sentiment: negative
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/882361/000117184323003043/0001171843-23-003043-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/882361/000117184323003043/f8k_050823.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-23-003043
- JSON: https://secwatch.observer/filing/0001171843-23-003043.json
- Plain text: https://secwatch.observer/filing/0001171843-23-003043.txt

## Key facts
- Earnings Releases
  Aptose Biosciences Inc. reported first quarter ended March 31, 2023 results: net income $ (13,676 ), EPS $ (0.15 ).
  - Period: first quarter ended March 31, 2023
  - Net income: $ (13,676 )
  - EPS: $ (0.15 )
  - Result: reported results
  source text: Aptose Biosciences, Inc. Statements of Operations Data (unaudited) ($ in thousands, except per share data) Three months ended March 31, 2023 March 31, 2022 Expenses: Research and development $ 8,811 $ 7,393 General and administrative 5,285 4,107 Operating expenses 14,096 11,500 Other income, net 420 19 Net loss $ (13,676 ) $ (11,481 ) Net Loss per share, Basic and diluted $ (0.15 ) $ (0.12 )
  evidence_url: https://www.sec.gov/Archives/edgar/data/882361/000117184323003043/0001171843-23-003043-index.htm

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