secwatch.observer — SEC 8-K summary
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Issuer:     Aptevo Therapeutics Inc. (APVO)
CIK:        0001671584
Form:       8-K
Filed at:   2025-09-16T23:59:59+00:00
Accession:  0001193125-25-205107
Event type: other_material
Sentiment:  positive
Materiality: 0.80
Item codes: 8.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

Aptevo reports 100% remission rate in Cohort 3 of Phase 1b/2 RAINIER trial for mipletamig in AML
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- 100% remission rate (CR/CRi) in Cohort 3 with mipletamig + venetoclax + azacitidine for newly diagnosed AML unfit for intensive chemo.
- No dose-limiting toxicities or cytokine release syndrome observed across all RAINIER cohorts; safety profile clean.
- 40% of treated patients achieved minimal residual disease (MRD)-negative status, a marker associated with improved outcomes.
- Cohort 4 now enrolling at next dose level; data expected at major medical conference in Q4 2025.
- Frontline AML market is multibillion-dollar; mipletamig could redefine standard of care if later-stage data confirm.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1671584/000119312525205107/0001193125-25-205107-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1671584/000119312525205107/apvo-20250916.htm
  HTML page:      https://secwatch.observer/filing/0001193125-25-205107

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer