---
schema_version: "secwatch.filing_event.v1"
accession: "0001559053-25-000029"
form_type: "8-K"
ticker: "PRTA"
cik: "0001559053"
company_name: "PROTHENA CORP PUBLIC LTD CO"
filed_at: "2025-08-04T23:59:59+00:00"
generated_at: "2026-05-17T21:26:45.681420+00:00"
event_type: "earnings"
sentiment: "negative"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# Prothena Q2 net loss $125.8M; prasinezumab to enter Phase 3 by end 2025

## Summary
- Net loss $125.8M vs income $66.9M last year; includes $32.6M restructuring charge and $44.9M non-cash tax allowance.
- Revenue $4.4M, down from $132.0M YoY; cash $372.3M with no debt; FY 2025 cash burn guidance $170-178M.
- Partner Roche plans Phase 3 start for prasinezumab in early Parkinson's by end 2025; peak sales potential >$3B.
- Initial Phase 1 data for PRX012 in Alzheimer's expected August 2025; up to $105M milestones possible in 2026.
- Prothena to hold EGM by year-end to vote on share capital reduction for potential share redemption program.

## SEC filing metadata
- accession: 0001559053-25-000029
- form_type: 8-K
- ticker: PRTA
- cik: 0001559053
- company_name: PROTHENA CORP PUBLIC LTD CO
- filed_at: 2025-08-04T23:59:59+00:00
- event_type: earnings
- sentiment: negative
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1559053/000155905325000029/0001559053-25-000029-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1559053/000155905325000029/prta-20250804.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001559053-25-000029
- JSON: https://secwatch.observer/filing/0001559053-25-000029.json
- Plain text: https://secwatch.observer/filing/0001559053-25-000029.txt

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