X4 Pharmaceuticals is developing novel therapeutics designed to improve immune cell trafficking to treat rare diseases, including primary immunodeficiencies and cancer.

The company’s oral small molecule drug candidates antagonize the CXCR4 pathway, which plays a central role in immune surveillance. X4’s most advanced product candidate, X4P-001, is in a Phase II clinical trial in patients with WHIM syndrome, a rare genetic, primary immunodeficiency disease, and is currently also under investigation in multiple clinical trials in oncology.

A Phase III trial of X4P-001 in WHIM syndrome is expected to begin in the first half of 2019.

X4 was founded and is led by several former members of the Genzyme leadership team, and is located in Cambridge, Massachusetts.

In March 2019, the company announced the completion of its merger with Arsanis. Shares of the new X4 are set to begin trading on the Nasdaq exchange under the stock symbol XFOR.