---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-24-129018"
form_type: "8-K"
ticker: "APVO"
cik: "0001671584"
company_name: "Aptevo Therapeutics Inc."
filed_at: "2024-11-20T23:59:59+00:00"
generated_at: "2026-05-29T21:56:45.590066+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Aptevo reports first RAINIER trial patient achieved 90% leukemic blast reduction in 30 days

## Summary
- First patient in Phase 1b/2 RAINIER trial achieved 90% reduction in leukemic blasts within first 30 days.
- Mipletamig (CD3 x CD123 bispecific) evaluated as frontline therapy in combination with venetoclax and azacitidine for AML.
- Data builds on prior studies showing strong safety profile with manageable CRS below comparable treatment modalities.
- RAINIER is designed for statistically defined efficacy analysis in newly diagnosed patients with limited options.

## SEC filing metadata
- accession: 0000950170-24-129018
- form_type: 8-K
- ticker: APVO
- cik: 0001671584
- company_name: Aptevo Therapeutics Inc.
- filed_at: 2024-11-20T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1671584/000095017024129018/0000950170-24-129018-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1671584/000095017024129018/apvo-20241120.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-24-129018
- JSON: https://secwatch.observer/filing/0000950170-24-129018.json
- Plain text: https://secwatch.observer/filing/0000950170-24-129018.txt

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