---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-24-018773"
form_type: "8-K"
ticker: "XFOR"
cik: "0001501697"
company_name: "X4 Pharmaceuticals, Inc"
filed_at: "2024-04-29T23:59:59+00:00"
generated_at: "2026-06-03T05:30:08.638131+00:00"
event_type: "regulatory"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# X4 Pharma receives FDA approval for XOLREMDI (mavorixafor), first drug for WHIM syndrome

## Summary
- XOLREMDI approved for patients 12+ with WHIM syndrome to increase circulating neutrophils and lymphocytes.
- Phase 3 4WHIM trial met primary endpoint (TAT-ANC) vs. placebo (p<0.0001).
- XOLREMDI showed 60% reduction in annualized infection rate vs. placebo.
- X4 granted Rare Pediatric Disease Priority Review Voucher concurrent with approval.
- U.S. commercial launch via specialty pharmacy PANTHERx Rare; X4Connect patient support launched.

## SEC filing metadata
- accession: 0001628280-24-018773
- form_type: 8-K
- ticker: XFOR
- cik: 0001501697
- company_name: X4 Pharmaceuticals, Inc
- filed_at: 2024-04-29T23:59:59+00:00
- event_type: regulatory
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 7.01, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1501697/000162828024018773/0001628280-24-018773-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1501697/000162828024018773/xfor-20240429.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-24-018773
- JSON: https://secwatch.observer/filing/0001628280-24-018773.json
- Plain text: https://secwatch.observer/filing/0001628280-24-018773.txt

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