---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-223434"
form_type: "8-K"
ticker: "STRO"
cik: "0001382101"
company_name: "SUTRO BIOPHARMA, INC."
filed_at: "2025-09-29T23:59:59+00:00"
generated_at: "2026-05-17T05:23:07.254724+00:00"
event_type: "other_material"
sentiment: "negative"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Sutro Biopharma cuts workforce ~33%; extends cash runway to mid-2027

## Summary
- Workforce reduction of approximately one-third to prioritize three preclinical ADC programs.
- Expected cash runway extended into at least mid-2027 due to restructuring and milestone payments.
- Initial clinical data from STRO-004 (Tissue Factor-targeting exatecan ADC) expected in 2026.
- Restructuring costs estimated at $4.1-4.3 million, with majority paid in Q4 2025.
- Company plans to initiate clinical studies for at least one additional ADC program beyond STRO-004.

## SEC filing metadata
- accession: 0001193125-25-223434
- form_type: 8-K
- ticker: STRO
- cik: 0001382101
- company_name: SUTRO BIOPHARMA, INC.
- filed_at: 2025-09-29T23:59:59+00:00
- event_type: other_material
- sentiment: negative
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 2.05, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1382101/000119312525223434/0001193125-25-223434-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1382101/000119312525223434/stro-20250929.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-223434
- JSON: https://secwatch.observer/filing/0001193125-25-223434.json
- Plain text: https://secwatch.observer/filing/0001193125-25-223434.txt

## Key facts
- Restructurings & Charges
  SUTRO BIOPHARMA, INC. announced a restructuring with charges of approximately $4.1million to $4.3 million (approximately one-third).
  - Type: restructuring
  - Charge: approximately $4.1million to $4.3 million
  - Headcount: approximately one-third
  source text: As part of the corporate restructuring, the Company plans to reduce its workforce by approximately one-third. The total cash payments and costs related to the further prioritization of the ADC programs and reducing the workforce are estimated to be approximately $4.1million to $4.3 million
  evidence_url: https://www.sec.gov/Archives/edgar/data/1382101/000119312525223434/0001193125-25-223434-index.htm

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