---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-21-349137"
form_type: "8-K"
ticker: "ACAD"
cik: "0001070494"
company_name: "ACADIA PHARMACEUTICALS INC"
filed_at: "2021-12-06T23:59:59+00:00"
generated_at: "2026-06-28T03:23:34.889448+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Acadia reports positive Phase 3 trofinetide results in Rett syndrome; NDA plan mid-2022

## Summary
- Trofinetide met co-primary endpoints: RSBQ change -5.1 vs -1.7 (p=0.0175); CGI-I 3.5 vs 3.8 (p=0.003).
- Key secondary endpoint CSBS-DP-IT-Social also met: -0.1 vs -1.1 (p=0.0064); effect size 0.43.
- Discontinuation due to AEs 17.2% trofinetide vs 2.1% placebo; diarrhea (80.6%) and vomiting (26.9%) most common.
- Pre-NDA meeting with FDA planned Q1 2022; NDA submission expected mid-2022; Fast Track, Orphan, RPD designations granted.
- More than 95% of completers rolled into open-label Lilac extension; Acadia licensed trofinetide from Neuren Pharmaceuticals.

## SEC filing metadata
- accession: 0001193125-21-349137
- form_type: 8-K
- ticker: ACAD
- cik: 0001070494
- company_name: ACADIA PHARMACEUTICALS INC
- filed_at: 2021-12-06T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- 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/1070494/000119312521349137/0001193125-21-349137-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1070494/000119312521349137/d257158d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-21-349137
- JSON: https://secwatch.observer/filing/0001193125-21-349137.json
- Plain text: https://secwatch.observer/filing/0001193125-21-349137.txt

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