X4 Pharmaceuticals is making strides in expanding the availability of mavorixafor, a potential treatment for WHIM syndrome, in Europe. The European Medicines Agency (EMA) has validated the Marketing Authorization Application (MAA) for mavorixafor, marking a significant step toward potential approval in the European Union.
Mavorixafor, a selective CXCR4 receptor antagonist, has already received approval in the United States under the brand name XOLREMDI. It is used as an oral, once-daily treatment for patients 12 years and older with WHIM syndrome, a rare primary immunodeficiency. The drug aims to increase the number of circulating mature neutrophils and lymphocytes in affected individuals.
The MAA submission is supported by positive results from the global, pivotal Phase 3 4WHIM clinical trial. The trial met its primary endpoint and a key secondary endpoint, demonstrating that mavorixafor was generally well-tolerated. There were no treatment-related serious adverse events reported, and no discontinuations due to safety concerns. The study also showed that once-daily oral mavorixafor led to reductions in the rate, severity, and duration of infections in participants with WHIM syndrome.
Commercialization Strategy
To facilitate the commercialization of mavorixafor in Europe, Australia, and New Zealand, X4 Pharmaceuticals has entered into an exclusive licensing and supply agreement with Norgine, a European specialist pharmaceutical company. Under the terms of the agreement, X4 will receive an upfront payment of €28.5 million and is eligible for up to €226 million in potential regulatory and commercial milestone payments, in addition to tiered, double-digit royalties up to the mid-twenties on future net sales in the licensed territories.
Paula Ragan, Ph.D., President and Chief Executive Officer of X4 Pharmaceuticals, stated, "Making mavorixafor available to those in the European Union living with WHIM syndrome is a top priority for X4, and this submission demonstrates our continued ability to deliver on our key milestones and generate growth."
Janneke van der Kamp, Chief Executive Officer of Norgine, commented, "We are very pleased to partner with X4 in this underserved, rare disease space and expand access to mavorixafor to patients in Europe, Australia, and New Zealand."
About WHIM Syndrome
WHIM syndrome, named for its four classic manifestations—warts, hypogammaglobulinemia, infections, and myelokathexis—is a rare, combined primary immunodeficiency and chronic neutropenic disorder caused by CXCR4 receptor dysfunction. This dysfunction impairs the mobilization of white blood cells from the bone marrow into peripheral circulation. People with WHIM syndrome often have low blood levels of neutrophils (neutropenia) and lymphocytes (lymphopenia), leading to serious and/or frequent infections. It is estimated that approximately 1,000 people are diagnosed with WHIM syndrome in the U.S., with another 1,000 estimated in Europe.
If approved by the EMA, mavorixafor would be the first drug indicated for patients with WHIM syndrome in Europe, addressing a significant unmet medical need for this patient population. The decision on the MAA is expected in the first half of 2026.
