---
schema_version: "secwatch.filing_event.v1"
accession: "0001725160-25-000082"
form_type: "8-K"
ticker: "ZNTL"
cik: "0001725160"
company_name: "Zentalis Pharmaceuticals, Inc."
filed_at: "2025-04-28T23:59:59+00:00"
generated_at: "2026-05-23T05:04:49.114346+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Azenosertib shows RB1 loss sensitivity in SCLC/TNBC; cfDNA MR predicts HGSOC response

## Summary
- Preclinical: RB1 loss sensitizes TP53-mutant SCLC/TNBC cells; in vivo TGI 90% in RB1-mutant vs 49% in WT xenografts (Ex-99.1).
- Clinical (N=123 HGSOC): cfDNA TP53 molecular response (MR) predicts RECIST response; MR+ median TTP 5.49 vs 2.69 months for MR- (HR 0.43, p<0.0001).
- Complete MR (mCR) yields 6.5-month median TTP; MR precedes RECIST by 14 weeks for responders and 8 weeks for progressors (Ex-99.2).
- Azenosertib shows synergistic activity with encorafenib + cetuximab in BRAF V600E preclinical models (Ex-99.4).

## SEC filing metadata
- accession: 0001725160-25-000082
- form_type: 8-K
- ticker: ZNTL
- cik: 0001725160
- company_name: Zentalis Pharmaceuticals, Inc.
- filed_at: 2025-04-28T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1725160/000172516025000082/0001725160-25-000082-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1725160/000172516025000082/zntl-20250427.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001725160-25-000082
- JSON: https://secwatch.observer/filing/0001725160-25-000082.json
- Plain text: https://secwatch.observer/filing/0001725160-25-000082.txt

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