---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-381098"
form_type: "8-K"
ticker: "APVO"
cik: "0001671584"
company_name: "Aptevo Therapeutics Inc."
filed_at: "2026-09-03T12:15:14+00:00"
generated_at: "2026-09-03T12:20:09.146086+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Aptevo reports 93% clinical benefit rate with mipletamig triplet in TP53-mutated AML

## Summary
- Of 14 evaluable TP53-mutated frontline AML patients, 13 (93%) achieved clinical benefit; 11 (79%) achieved CR/CRi, including 9 CRs.
- 79% CR/CRi compares favorably to published 41% composite remission rate for venetoclax plus azacitidine in this population.
- RAINIER dose optimization trial expected to complete by year-end 2026; regulatory interaction planned for 1H27.
- Data include two patients from previously completed dose expansion trial; mipletamig combined with venetoclax and azacitidine.

## SEC filing metadata
- accession: 0001193125-26-381098
- form_type: 8-K
- ticker: APVO
- cik: 0001671584
- company_name: Aptevo Therapeutics Inc.
- filed_at: 2026-09-03T12:15:14+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1671584/000119312526381098/0001193125-26-381098-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1671584/000119312526381098/apvo-20260903.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-381098
- JSON: https://secwatch.observer/filing/0001193125-26-381098.json
- Plain text: https://secwatch.observer/filing/0001193125-26-381098.txt

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