Leveraging our unparalleled expertise in diseases of the immune system and CXCR4 biology, we aim to bring innovative treatments to patients with chronic neutropenic disorders. Our lead product candidate, mavorixafor, is a first-in-class CXCR4 inhibitor being developed as a once-daily, oral therapy for people with chronic neutropenic disorders. Mavorixafor has demonstrated the ability to mobilize immune cells from the bone marrow into the bloodstream, creating what we believe to be broad commercial potential in the estimated 50,000 (U.S.) diagnosed chronic neutropenia patients who currently have few to no treatment options. We are currently evaluating the safety and efficacy of mavorixafor in a Phase 3 clinical trial for the treatment of people with WHIM syndrome; data from this Phase 3 study (4WHIM) are expected in the fourth quarter of 2022. We are also conducting a Phase 1b clinical trial of mavorixafor in people with idiopathic, cyclic, or congenital neutropenia. Based on positive data from the first part of this Phase 1b trial, we are currently amending and expanding the study to evaluate chronic use of daily oral mavorixafor with or without G-CSF in up to 50 participants with chronic neutropenic disorders. X4 is a public biopharmaceutical company (Nasdaq: XFOR) headquartered in Boston, Massachusetts, with a research center of excellence in Vienna, Austria.