---
schema_version: "secwatch.filing_event.v1"
accession: "0001683168-25-002725"
form_type: "8-K"
ticker: "PHIO"
cik: "0001533040"
company_name: "Phio Pharmaceuticals Corp."
filed_at: "2025-04-22T23:59:59+00:00"
generated_at: "2026-05-23T09:15:16.099270+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.4
calibrated_materiality_score: 0.4
confidence: "high"
source: SEC EDGAR
---

# Phio Pharmaceuticals dismisses BDO and engages Grant Thornton as auditor

## Summary
- Audit Committee dismissed BDO USA as independent auditor effective April 17, 2025.
- Grant Thornton LLP appointed as new independent auditor for fiscal year ending Dec 31, 2025.
- No disagreements or reportable events occurred during BDO's tenure through April 17, 2025.
- BDO's reports for FY2024 and FY2023 included going-concern explanatory paragraphs.

## SEC filing metadata
- accession: 0001683168-25-002725
- form_type: 8-K
- ticker: PHIO
- cik: 0001533040
- company_name: Phio Pharmaceuticals Corp.
- filed_at: 2025-04-22T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.4
- calibrated_materiality_score: 0.4
- confidence: high
- sec_items: 4.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1533040/000168316825002725/0001683168-25-002725-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1533040/000168316825002725/phio_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001683168-25-002725
- JSON: https://secwatch.observer/filing/0001683168-25-002725.json
- Plain text: https://secwatch.observer/filing/0001683168-25-002725.txt

## Key facts
- Auditor Changes
  Phio Pharmaceuticals Corp. engaged Grant Thornton LLP as its auditor.
  - Action: engagement
  - Auditor: Grant Thornton LLP
  source text: Also on April 17, 2025, the Audit Committee approved the engagement of Grant Thornton LLP ("Grant Thornton") as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2025, effective immediately.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1533040/000168316825002725/0001683168-25-002725-index.htm
- Auditor Changes
  Phio Pharmaceuticals Corp. dismissed BDO USA, P.C. as its auditor.
  - Action: dismissal
  - Auditor: BDO USA, P.C.
  - Successor: Grant Thornton LLP
  source text: on April 17, 2025, the Audit Committee approved the dismissal of BDO USA, P.C. ("BDO") as the Company's independent registered public accounting firm, effective immediately.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1533040/000168316825002725/0001683168-25-002725-index.htm

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