---
schema_version: "secwatch.filing_event.v1"
accession: "0001193805-23-000929"
form_type: "8-K"
ticker: "ARCT"
cik: "0001768224"
company_name: "Arcturus Therapeutics Holdings Inc."
filed_at: "2023-06-30T23:59:59+00:00"
generated_at: "2026-06-13T14:13:00.642141+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Meiji submits additional application in Japan for booster dose of Arcturus' COVID-19 vaccine ARCT-154

## Summary
- Meiji Seika Pharma submitted a booster dose application for ARCT-154 in Japan based on Phase III data meeting primary endpoint.
- This follows the April 28 NDA for primary immunization; ARCT-154 is a self-amplifying mRNA vaccine developed by Arcturus.
- The Phase III trial (jRCT2071220080) compared ARCT-154 to COMIRNATY booster; no clinically significant safety concerns.
- If approved, ARCT-154 would be a new COVID-19 vaccination option in Japan; distribution via CSL Seqirus agreement.

## SEC filing metadata
- accession: 0001193805-23-000929
- form_type: 8-K
- ticker: ARCT
- cik: 0001768224
- company_name: Arcturus Therapeutics Holdings Inc.
- filed_at: 2023-06-30T23:59:59+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1768224/000119380523000929/0001193805-23-000929-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1768224/000119380523000929/e618740_8k-arct.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193805-23-000929
- JSON: https://secwatch.observer/filing/0001193805-23-000929.json
- Plain text: https://secwatch.observer/filing/0001193805-23-000929.txt

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