# X4 Pharmaceuticals

Source: https://onco.cc/companies/x4-pharmaceuticals/  
OnCo record `x4-pharmaceuticals` (Company). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

X4 Pharmaceuticals is a Boston biotech whose oral CXCR4 blocker mavorixafor won approval as Xolremdi for WHIM syndrome and is being tested to free neutrophils in chronic neutropenia and to open tumours to immune attack.

## Summary

X4 Pharmaceuticals develops mavorixafor (X4P-001, formerly AMD-070), an oral antagonist of the chemokine receptor CXCR4. The FDA approved it in April 2024 as Xolremdi for patients aged 12 and older with WHIM syndrome, a rare immunodeficiency. The phase 3 4WARD trial tests it in chronic neutropenia. In oncology the drug has been studied with axitinib in renal cell carcinoma, with pembrolizumab in melanoma and in Waldenström macroglobulinaemia, where CXCR4 mutations confer resistance to BTK inhibitors.

## Fields

- Kind: Company
- Last checked: 2026-09-17
- Also known as: X4 Pharmaceuticals, Inc.; NASDAQ:XFOR
- Tags: drug-maker
- HQ: Boston, Massachusetts
- Type: biotech
- Website: https://www.x4pharma.com/
- Ticker: NASDAQ:XFOR

## Sources

- Official website: https://www.x4pharma.com/

## Connected records

- drugs: [Mavorixafor](https://onco.cc/drugs/mavorixafor/)

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