X4 Pharmaceuticals (XFOR) announced Monday the presentation of positive results from its completed Phase 2 clinical trial of mavorixafor for the treatment of primary chronic neutropenia or CN at the 30th Annual Congress of the European Hematology Association or EHA in Milan, Italy.
The open-label, six-month Phase 2 study evaluated oral, once-daily mavorixafor in 23 participants with idiopathic, congenital, or cyclic chronic neutropenia.
Patients received either mavorixafor monotherapy or a combination of mavorixafor with injectable granulocyte colony-stimulating factor or G-CSF.
Poster presentations at EHA highlighted that mavorixafor durably increased absolute neutrophil counts or ANC over the study period.
In patients with severe CN, mean ANC levels increased nearly three-fold over six months, reaching target levels typically sought by clinicians.
Importantly, 89% of participants and investigators chose to reduce or discontinue G-CSF during the trial, while maintaining ANC in the normal range, signaling strong potential for mavorixafor to reduce reliance on injectable therapies.
Functional neutrophil levels in treated patients were also found to be comparable to those of healthy donors after six months of treatment.
Mavorixafor was generally well tolerated as both monotherapy and in combination with G-CSF, with no serious drug-related adverse events reported. The safety profile was consistent with earlier studies.
X4 is currently enrolling patients in its global, pivotal Phase 3 4WARD trial, a 52-week randomized, placebo-controlled study evaluating mavorixafor with or without G-CSF in up to 150 participants with congenital, autoimmune, or idiopathic CN.
The primary endpoints include a reduction in annualized infection rates and ANC response.
Mavorixafor, an oral CXCR4 antagonist, is designed to mobilize functional neutrophils from the bone marrow into circulation. It is already approved in the U.S. as XOLREMDI for a separate indication and is being evaluated for additional rare immune-related disorders.
Currently, XFOR is trading at $2.80, down by 0.70 percent on the Nasdaq.
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