X4 Pharmaceuticals Announces Submission of New Drug Application (NDA) to U.S. FDA for Mavorixafor in WHIM Syndrome

Submission supported by positive results from global, pivotal 4WHIM Phase 3 clinical trial

BOSTON, Sept. 05, 2023 (GLOBE NEWSWIRE) -- X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today announced the submission of a New Drug Application (NDA) to the United States Food and Drug Administration (FDA) for the approval of once-daily, oral mavorixafor to treat individuals aged 12 and older with WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare, primary immunodeficiency.

“The submission of our first NDA is a significant milestone in X4's journey to transform the care of those living with rare immunodeficiencies,” said Paula Ragan, Ph.D., President and Chief Executive Officer of X4 Pharmaceuticals. “We’re excited that this submission moves us one step closer to introducing what could be the first approved product in the U.S. for those with WHIM syndrome. We also continue to advance our clinical program evaluating mavorixafor in people with chronic neutropenic disorders.”

The FDA takes 60 days to determine whether an NDA is sufficiently complete prior to accepting it for filing. X4 has requested priority review for the application which, if granted, would provide a target FDA review period of six months from the application acceptance for filing date.

The NDA submission is supported by the results of the global, pivotal, 4WHIM Phase 3 clinical trial of once-daily, oral mavorixafor in individuals with WHIM syndrome. The 4WHIM trial met its primary endpoint and key secondary endpoint and was generally well tolerated in the trial, with no treatment-related serious adverse events reported and no discontinuations for safety events. The 4WHIM data also revealed that mavorixafor treatment resulted in reductions in the rate, severity, and duration of infections in trial participants versus placebo. These and additional 4WHIM Phase 3 data were published in oral presentations at the annual meetings of both the Clinical Immunology Society (CIS) and European Hematology Association (EHA).

About Mavorixafor and WHIM Syndrome
WHIM syndrome is a rare, inherited, combined immunodeficiency disease caused by reduced mobilization and trafficking of white blood cells from the bone marrow due to over-signaling of the CXCR4/CXCL12 pathway. WHIM syndrome is named for its four common clinical findings: Warts, Hypogammaglobulinemia, Infections, and Myelokathexis, although not all patients experience all symptoms, and not all symptoms are required for a diagnosis. People with WHIM syndrome characteristically have very low blood levels of neutrophils (neutropenia) and lymphocytes (lymphopenia), and as a result, experience frequent, recurrent infections with a high risk of lung disease, refractory warts from underlying human papillomavirus (HPV) infection, limited antibody production due to low levels of immunoglobulin, and an increased risk of developing certain types of cancer.