---
schema_version: "secwatch.filing_event.v1"
accession: "0001559053-22-000021"
form_type: "8-K"
ticker: "PRTA"
cik: "0001559053"
company_name: "PROTHENA CORP PUBLIC LTD CO"
filed_at: "2022-05-05T23:59:59+00:00"
generated_at: "2026-06-25T23:39:27.640186+00:00"
event_type: "earnings"
sentiment: "neutral"
materiality_score: 0.55
calibrated_materiality_score: 0.55
confidence: "high"
source: SEC EDGAR
---

# Prothena Q1 net loss $36.3M; PRX012 gets Fast Track, Phase 1 started

## Summary
- Net loss of $36.3M ($0.78 per share) vs $36.7M loss ($0.91) in Q1 2021; revenue $1.2M.
- Cash and restricted cash $544.3M at quarter end; no debt; net cash used in ops/investing $37.4M.
- PRX012 initiated Phase 1 SAD study, received FDA Fast Track for Alzheimer's disease.
- R&D expense $27.3M (up 29% YoY) driven by birtamimab, PRX012, PRX005 programs.
- FY 2022 guidance: net cash outflow $120-132M, net loss $154-170M, year-end cash ~$454M.

## SEC filing metadata
- accession: 0001559053-22-000021
- form_type: 8-K
- ticker: PRTA
- cik: 0001559053
- company_name: PROTHENA CORP PUBLIC LTD CO
- filed_at: 2022-05-05T23:59:59+00:00
- event_type: earnings
- sentiment: neutral
- materiality_score: 0.55
- calibrated_materiality_score: 0.55
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1559053/000155905322000021/0001559053-22-000021-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1559053/000155905322000021/prta-20220505.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001559053-22-000021
- JSON: https://secwatch.observer/filing/0001559053-22-000021.json
- Plain text: https://secwatch.observer/filing/0001559053-22-000021.txt

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