X4 Pharmaceuticals, Inc. filed a Current Report on Form 8-K with the Securities and Exchange Commission on October 29, 2026, to disclose an investor presentation. The document indicates that the presentation, filed as Exhibit 99.1, is intended for use during the Company’s October 29, 2029 Investor Day event.
The filing outlines the Company’s clinical and commercial strategy for mavorixafor, its oral CXCR4 antagonist. The presentation highlights the ongoing pivotal Phase 3 4WARD study in Primary Chronic Neutropenia (PCN). The Company expects full enrollment of 126 patients in the 4WARD trial by the end of Q4 2026, with top-line data anticipated in Q1 2028. Management estimates a potential U.S. FDA approval for mavorixafor in PCN in late 2028 or early 2029.
In addition to the 4WARD trial, the presentation details a planned Phase 2b study titled 4STEPS. This study aims to evaluate the safety and tolerability of reducing granulocyte colony-stimulating factor (G-CSF) dosage in patients receiving mavorixafor. The 4STEPS trial is designed to enroll approximately 25 patients across roughly 25 sites in the U.S. and the U.K., with the first patient visit expected in Q1 2027.
The filing also notes that mavorixafor is currently approved in the U.S. for Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) syndrome under the brand name XOLREMDI, and has received approval from the European Commission in 2026.
