---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-113599"
form_type: "8-K/A"
ticker: "CYTK"
cik: "0001061983"
company_name: "CYTOKINETICS INC"
filed_at: "2025-09-08T23:59:59+00:00"
generated_at: "2026-05-17T07:28:02.740973+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Cytokinetics presents positive aficamten data at ESC 2025; PDUFA Dec 26, 2025

## Summary
- MAPLE-HCM: aficamten improved cardiac structure/function vs metoprolol (p<0.001 for diastolic function, SAM reduction); published in JACC.
- New analysis shows aficamten AF incidence 1.5%/year, consistent with HCM prediction model (3.6%/year) and healthy model (1.4%/year); published in Heart Rhythm.
- FOREST-HCM: 93% of patients had ≥1 NYHA class improvement at 96 weeks; sustained hemodynamic benefits with low LVEF <50% (0.3% discontinuation).
- Integrated safety (463 patients, ~700 patient-years): aficamten well-tolerated, AE profile similar to placebo; new-onset AF 1.9% vs placebo 2%.
- FDA NDA under review; PDUFA target action date December 26, 2025.

## SEC filing metadata
- accession: 0000950170-25-113599
- form_type: 8-K/A
- ticker: CYTK
- cik: 0001061983
- company_name: CYTOKINETICS INC
- filed_at: 2025-09-08T23:59:59+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/1061983/000095017025113599/0000950170-25-113599-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1061983/000095017025113599/cytk-20250831.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-113599
- JSON: https://secwatch.observer/filing/0000950170-25-113599.json
- Plain text: https://secwatch.observer/filing/0000950170-25-113599.txt

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