---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-24-135609"
form_type: "8-K"
ticker: "APVO"
cik: "0001671584"
company_name: "Aptevo Therapeutics Inc."
filed_at: "2024-12-12T23:59:59+00:00"
generated_at: "2026-05-29T04:08:21.339134+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Aptevo: 100% remission in Cohort 1 of mipletamig frontline AML trial; 2 of 3 patients MRD-negative

## Summary
- 100% of patients (3/3) achieved remission within 30 days in Cohort 1 of RAINIER Phase 1b trial.
- Two patients achieved complete remission with MRD-negative status, including one with TP53 mutation.
- Results build on prior trial where 100% of frontline patients also achieved remission.
- Mipletamig continues to show favorable safety and tolerability profile; Cohort 2 enrollment commencing.

## SEC filing metadata
- accession: 0000950170-24-135609
- form_type: 8-K
- ticker: APVO
- cik: 0001671584
- company_name: Aptevo Therapeutics Inc.
- filed_at: 2024-12-12T23:59:59+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/1671584/000095017024135609/0000950170-24-135609-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1671584/000095017024135609/apvo-20241212.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-24-135609
- JSON: https://secwatch.observer/filing/0000950170-24-135609.json
- Plain text: https://secwatch.observer/filing/0000950170-24-135609.txt

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