---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-310509"
form_type: "8-K"
ticker: "FULC"
cik: "0001680581"
company_name: "Fulcrum Therapeutics, Inc."
filed_at: "2025-12-08T23:59:59+00:00"
generated_at: "2026-05-16T13:59:00.475017+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.85
calibrated_materiality_score: 0.85
confidence: "high"
source: SEC EDGAR
---

# Fulcrum reports positive Phase 1b data for pociredir in SCD: 58% patients achieved HbF>=20% at 20 mg dose

## Summary
- Mean absolute HbF increased 9.9% at Week 6 in 20 mg cohort (vs 5.6% in 12 mg); 7 of 12 patients (58%) achieved HbF ≥20%.
- Clear dose-response: >3.75-fold mean HbF induction at Week 12 (n=6) vs 2.4-fold in 12 mg cohort.
- Hemolysis markers improved at Week 6: indirect bilirubin -37%, LDH -37%, reticulocyte counts -33%.
- Pociredir well-tolerated with no treatment-related SAEs or discontinuations; dosed in 148 adults to date.
- Plans to submit IND for bone marrow failure syndromes (e.g., Diamond-Blackfan anemia) in Q2 2026.

## SEC filing metadata
- accession: 0001193125-25-310509
- form_type: 8-K
- ticker: FULC
- cik: 0001680581
- company_name: Fulcrum Therapeutics, Inc.
- filed_at: 2025-12-08T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.85
- calibrated_materiality_score: 0.85
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1680581/000119312525310509/0001193125-25-310509-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1680581/000119312525310509/fulc-20251208.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-310509
- JSON: https://secwatch.observer/filing/0001193125-25-310509.json
- Plain text: https://secwatch.observer/filing/0001193125-25-310509.txt

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