X4 Pharmaceuticals’ Mavorixafor Shows Positive Results In Chronic Neutropenia Phase 2 Trial

X4 Pharmaceuticals, a company focused on enhancing the lives of people with rare immune disorders, has announced promising new data from its recently completed Phase 2 trial of mavorixafor, an oral CXCR4 antagonist, for treating chronic neutropenia (CN). Findings from the six-month study indicate that a daily dose of mavorixafor significantly and sustainably raised the participants' average absolute neutrophil counts (ANC). In addition, when used along with injectable granulocyte colony-stimulating factor (G-CSF), mavorixafor allowed a reduction in G-CSF doses while maintaining normal ANC levels.

Teresa Tarrant, M.D., Associate Professor of Medicine, Rheumatology, and Immunology at Duke University School of Medicine, said in a statement, “Since the U.S. approval of G-CSF to treat severe chronic neutropenia, there has remained a significant unmet need for an optimal treatment in terms of long-term efficacy, safety, and route of administration. 

She also commented, “I am encouraged by these Phase 2 results showing that mavorixafor increased circulating neutrophils across study participants and that these neutrophils were functional in a sub-study population. The larger Phase 3 mavorixafor CN trial will expand on these data, and I remain optimistic about this potential much-needed innovation for patients with chronic neutropenia.”

“We could not be more pleased with the results from the six-month Phase 2 study of mavorixafor in CN, consistent with our earlier findings that mavorixafor durably and meaningfully increased ANC in this population. Importantly, we gained insights into the potential real-world use of mavorixafor in CN, should we ultimately obtain approval. These data not only confirm our interim findings but also increase our confidence in a positive outcome for our ongoing pivotal Phase 3 4WARD trial and the potential of mavorixafor to help people living with chronic neutropenia,” stated Paula Ragan, PhD, President and Chief Executive Officer of X4 Pharmaceuticals.