---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-23-023505"
form_type: "8-K"
ticker: "CYTK"
cik: "0001061983"
company_name: "CYTOKINETICS INC"
filed_at: "2023-05-23T23:59:59+00:00"
generated_at: "2026-06-14T16:59:49.835160+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Cytokinetics reports positive Phase 2 data for aficamten in nHCM; Phase 3 to start 2H 2023

## Summary
- At 10 weeks, aficamten improved KCCQ-CSS by 10.6 points (p<0.0001); 58% of patients had clinical symptom reduction.
- 56% of patients improved ≥1 NYHA class; 28% became asymptomatic (Class I) by Week 10.
- Mean relative reductions: NT-proBNP 55% (p<0.0001) and high-sensitivity troponin I 21% (p<0.005).
- In 14 patients with baseline angina, SAQ-AF score reduced 14.3 points (p=0.005), converting daily/weekly angina to weekly/monthly.
- Aficamten well-tolerated; no discontinuations due to AEs, no LVEF<40%, and phase 3 trial planned for 2H 2023.

## SEC filing metadata
- accession: 0000950170-23-023505
- form_type: 8-K
- ticker: CYTK
- cik: 0001061983
- company_name: CYTOKINETICS INC
- filed_at: 2023-05-23T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1061983/000095017023023505/0000950170-23-023505-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1061983/000095017023023505/cytk-20230520.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-23-023505
- JSON: https://secwatch.observer/filing/0000950170-23-023505.json
- Plain text: https://secwatch.observer/filing/0000950170-23-023505.txt

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