---
schema_version: "secwatch.filing_event.v1"
accession: "0001559053-23-000025"
form_type: "8-K"
ticker: "PRTA"
cik: "0001559053"
company_name: "PROTHENA CORP PUBLIC LTD CO"
filed_at: "2023-08-03T23:59:59+00:00"
generated_at: "2026-06-12T08:10:04.373573+00:00"
event_type: "earnings"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Prothena Q2 net loss $54.6M, revises FY cash guidance up to ~$600M

## Summary
- Net loss $54.6M ($1.03/share) vs $41.2M loss in Q2 2022; revenue $4.0M (up from $1.3M).
- Cash, equivalents $661.3M at June 30; year-end cash guidance raised to ~$600M midpoint from $512M.
- Bristol Myers Squibb exercised $55M option for worldwide rights to PRX005 (anti-tau) in July 2023.
- PRX012 Phase 1 topline data expected year-end 2023; IND filing for PRX123 dual vaccine expected year-end.
- Billy Dunn (former FDA Office of Neuroscience Director) added to Board.

## SEC filing metadata
- accession: 0001559053-23-000025
- form_type: 8-K
- ticker: PRTA
- cik: 0001559053
- company_name: PROTHENA CORP PUBLIC LTD CO
- filed_at: 2023-08-03T23:59:59+00:00
- event_type: earnings
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1559053/000155905323000025/0001559053-23-000025-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1559053/000155905323000025/prta-20230803.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001559053-23-000025
- JSON: https://secwatch.observer/filing/0001559053-23-000025.json
- Plain text: https://secwatch.observer/filing/0001559053-23-000025.txt

## Key facts
- Earnings Releases
  PROTHENA CORP PUBLIC LTD CO updated its the second quarter ended June 30, 2023 guidance (lowered).
  - Period: the second quarter ended June 30, 2023
  - Guidance: lowered
  - Result: reported results
  source text: Prothena Corporation plc issued a press release announcing its financial results for the second quarter ended June 30, 2023.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1559053/000155905323000025/0001559053-23-000025-index.htm

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