---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-24-030243"
form_type: "8-K"
ticker: "XFOR"
cik: "0001501697"
company_name: "X4 Pharmaceuticals, Inc"
filed_at: "2024-06-27T23:59:59+00:00"
generated_at: "2026-06-01T00:59:09.317676+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# X4 reports positive Phase 2 mavorixafor data in chronic neutropenia; starts Phase 3 4WARD trial

## Summary
- 100% (6/6) evaluable participants achieved target ANC increase (>500 cells/µL) at Months 3 and 6 on mavorixafor ± G-CSF.
- Mavorixafor monotherapy achieved mean ANC ≥1,500 cells/µL at Months 3 and 6; severe CN patients had mean ANC ~800-1,000 cells/µL.
- Combination with stable-dose G-CSF increased mean ANC >1,000 cells/µL vs baseline at Months 1, 3, and 6.
- No drug-related serious adverse events; three discontinuations due to non-serious AEs.
- Global Phase 3 4WARD trial initiated (randomized, 150 patients, 52 weeks) for congenital, autoimmune, or idiopathic CN.

## SEC filing metadata
- accession: 0001628280-24-030243
- form_type: 8-K
- ticker: XFOR
- cik: 0001501697
- company_name: X4 Pharmaceuticals, Inc
- filed_at: 2024-06-27T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1501697/000162828024030243/0001628280-24-030243-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1501697/000162828024030243/xfor-20240627.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-24-030243
- JSON: https://secwatch.observer/filing/0001628280-24-030243.json
- Plain text: https://secwatch.observer/filing/0001628280-24-030243.txt

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