---
schema_version: "secwatch.filing_event.v1"
accession: "0001559053-23-000014"
form_type: "8-K"
ticker: "PRTA"
cik: "0001559053"
company_name: "PROTHENA CORP PUBLIC LTD CO"
filed_at: "2023-05-04T23:59:59+00:00"
generated_at: "2026-06-15T21:52:09.916453+00:00"
event_type: "earnings"
sentiment: "neutral"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Prothena Q1 net loss widens to $46.9M; pipeline progress with PRX012, PRX005 data

## Summary
- Net loss of $46.9M ($0.89 per share) vs $36.3M ($0.78) in Q1 2022; revenue $2.2M from BMS collaboration.
- Cash position $688.4M; FY 2023 guidance: net cash used $213-229M, year-end cash ~$512M.
- PRX012 preclinical data at AD/PD showed 20-fold higher affinity vs lecanemab; PRX005 Phase 1 SAD met safety objective.
- Key milestones: PRX012 topline data year-end 2023; birtamimab Phase 3 AFFIRM-AL topline in 2024.
- R&D expenses rose to $44.8M from $27.3M driven by clinical trial costs.

## SEC filing metadata
- accession: 0001559053-23-000014
- form_type: 8-K
- ticker: PRTA
- cik: 0001559053
- company_name: PROTHENA CORP PUBLIC LTD CO
- filed_at: 2023-05-04T23:59:59+00:00
- event_type: earnings
- sentiment: neutral
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 2.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1559053/000155905323000014/0001559053-23-000014-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1559053/000155905323000014/prta-20230504.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001559053-23-000014
- JSON: https://secwatch.observer/filing/0001559053-23-000014.json
- Plain text: https://secwatch.observer/filing/0001559053-23-000014.txt

## Key facts
- Earnings Releases
  PROTHENA CORP PUBLIC LTD CO reported first quarter of 2023 results: net income $46.9 million.
  - Period: first quarter of 2023
  - Net income: $46.9 million
  - Result: reported results
  source text: For the first quarter of 2023, Prothena reported net loss of $46.9 million
  evidence_url: https://www.sec.gov/Archives/edgar/data/1559053/000155905323000014/0001559053-23-000014-index.htm

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