X4 Pharmaceuticals Receives Positive Opinion from the EMA CHMP Recommending Approval of Mavorixafor in the EU for WHIM Syndrome

- Potential First and Only Therapy in the EU for Ultra-Rare Immune Disorder -

BOSTON, Feb. 27, 2026 (GLOBE NEWSWIRE) -- X4 Pharmaceuticals (Nasdaq: XFOR), a company focused on improving the lives of people with rare hematology diseases, today announced the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has adopted a positive opinion recommending the granting of marketing authorization, under exceptional circumstances, of mavorixafor for the treatment of WHIM syndrome in the European Union (EU). The positive opinion will now be reviewed by the European Commission (EC) with a final approval decision anticipated in the second quarter of 2026.

“This positive opinion from the CHMP for mavorixafor represents a key milestone toward making this treatment available to WHIM syndrome patients in the EU,” said Adam Craig, M.D., Ph.D., Executive Chairman of X4 Pharmaceuticals. “WHIM syndrome is an ultra-rare disease with a significant unmet medical need. We look forward to the EC's decision and to working with Norgine, our commercial partner in Europe, Australia and New Zealand, to ensure patient access upon a potential approval to the first and only therapy in Europe to treat this devastating condition.”

WHIM syndrome is an ultra-rare, inherited primary immunodeficiency named for its four classic manifestations: warts, hypogammaglobulinemia, infections, and myelokathexis. WHIM is caused by CXCR4 receptor dysfunction that results in impaired mobilization of white blood cells from the bone marrow into peripheral circulation resulting in serious and/or frequent infections.

Mavorixafor, a CXC chemokine receptor 4 antagonist, has been approved by the U.S. Food and Drug Administration (FDA) under the trade name XOLREMDI®, for use as an oral, once-daily therapy in patients 12 years of age and older with WHIM syndrome to increase the number of circulating mature neutrophils and lymphocytes. XOLREMDI is the first drug ever approved in the United States to treat WHIM syndrome.

The CHMP’s positive opinion for mavorixafor is supported by results from the pivotal, Phase 3 clinical trial (4WHIM), a global, randomized, double-blind, placebo-controlled, 52-week multicenter study that evaluated the efficacy and safety of XOLREMDI in 31 people aged 12 years and older diagnosed with WHIM syndrome. The efficacy of XOLREMDI was determined by improvement in absolute neutrophil counts (ANC), improvement in absolute lymphocyte counts (ALC), and a reduction in infections. In the 4WHIM trial, XOLREMDI treatment demonstrated increased time above threshold (≥500 cells/microliter) for absolute neutrophil count (TAT-ANC) vs. placebo (p