---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-006992"
form_type: "8-K"
ticker: "ATRA"
cik: "0001604464"
company_name: "Atara Biotherapeutics, Inc."
filed_at: "2025-01-21T23:59:59+00:00"
generated_at: "2026-05-27T22:09:50.298770+00:00"
event_type: "regulatory"
sentiment: "negative"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Atara Biotherapeutics receives FDA clinical hold on EBVALLO and ATA3219 programs

## Summary
- FDA clinical hold on EBVALLO and ATA3219 studies due to GMP compliance issues at third-party manufacturer.
- New patient enrollment paused; currently enrolled patients who may benefit can continue treatment.
- Clinical hold linked to inadequately addressed GMP issues from Jan 16 CRL for EBVALLO.
- Atara's second manufacturer FDB in Thousand Oaks unaffected; remains part of long-term strategy.
- FDA committed to working expeditiously with Atara to resolve clinical hold.

## SEC filing metadata
- accession: 0000950170-25-006992
- form_type: 8-K
- ticker: ATRA
- cik: 0001604464
- company_name: Atara Biotherapeutics, Inc.
- filed_at: 2025-01-21T23:59:59+00:00
- event_type: regulatory
- sentiment: negative
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1604464/000095017025006992/0000950170-25-006992-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1604464/000095017025006992/atra-20250121.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-006992
- JSON: https://secwatch.observer/filing/0000950170-25-006992.json
- Plain text: https://secwatch.observer/filing/0000950170-25-006992.txt

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