---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-097323"
form_type: "8-K"
ticker: "ALKS"
cik: "0001520262"
company_name: "Alkermes plc."
filed_at: "2025-07-21T23:59:59+00:00"
generated_at: "2026-05-18T05:02:27.004758+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.8
calibrated_materiality_score: 0.8
confidence: "high"
source: SEC EDGAR
---

# Alkermes reports positive phase 2 results for alixorexton in narcolepsy type 1; primary endpoint met

## Summary
- Alixorexton met primary endpoint: statistically significant and dose-dependent improvements in wakefulness (MWT) vs placebo (p<0.0001 at all doses).
- Key secondary: ESS improved significantly at all doses (p<0.0001); weekly cataplexy rates numerically improved, significant at 6 mg (p=0.005).
- Exploratory endpoints: alixorexton improved disease severity (NSS), cognition (BC-CCI), and fatigue (PROMIS-Fatigue) at all doses (p<0.01).
- Alixorexton was generally well tolerated; no serious AEs; >95% of patients entered open-label extension.
- Data support rapid initiation of global phase 3 program in NT1; detailed results at World Sleep Congress Sept 2025.

## SEC filing metadata
- accession: 0000950170-25-097323
- form_type: 8-K
- ticker: ALKS
- cik: 0001520262
- company_name: Alkermes plc.
- filed_at: 2025-07-21T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.8
- calibrated_materiality_score: 0.8
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1520262/000095017025097323/0000950170-25-097323-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1520262/000095017025097323/alks-20250721.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-097323
- JSON: https://secwatch.observer/filing/0000950170-25-097323.json
- Plain text: https://secwatch.observer/filing/0000950170-25-097323.txt

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