---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-23-000528"
form_type: "8-K"
ticker: "STRO"
cik: "0001382101"
company_name: "SUTRO BIOPHARMA, INC."
filed_at: "2023-01-09T23:59:59+00:00"
generated_at: "2026-06-20T17:37:39.331573+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Sutro STRO-002 Phase 1 shows 43.8% ORR in FolRα-selected ovarian cancer; registrational study Q2 2023

## Summary
- STRO-002 (luvelta) Phase 1 dose-expansion: 43.8% ORR, median DOR 5.4 mo, median PFS 6.6 mo at 5.2 mg/kg in FolRα-selected (TPS>25%) patients.
- FolRα-selected population (~80% of advanced ovarian cancer) drove benefit; unselected patients had 11.1% ORR.
- Prophylactic pegfilgrastim reduced Grade 3+ neutropenia 85% (66.7% to 10%) and dose delays 60.6% at cycle 2.
- Phase 2/3 registration-directed study REFRaME to start Q2 2023; potential accelerated approval based on ORR endpoint.

## SEC filing metadata
- accession: 0000950170-23-000528
- form_type: 8-K
- ticker: STRO
- cik: 0001382101
- company_name: SUTRO BIOPHARMA, INC.
- filed_at: 2023-01-09T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1382101/000095017023000528/0000950170-23-000528-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1382101/000095017023000528/stro-20230109.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-23-000528
- JSON: https://secwatch.observer/filing/0000950170-23-000528.json
- Plain text: https://secwatch.observer/filing/0000950170-23-000528.txt

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