X4 Pharmaceuticals (Nasdaq: XFOR) has announced positive results from its completed Phase 2 study evaluating mavorixafor in patients with chronic neutropenia (CN). The data indicate that the oral, once-daily drug was well-tolerated and led to meaningful increases in blood neutrophil counts, potentially reducing the need for granulocyte colony-stimulating factor (G-CSF) therapy.
Mavorixafor's Impact on Neutrophil Counts
The Phase 2 study demonstrated that mavorixafor significantly increased participants' mean absolute neutrophil counts (ANC). Notably, physicians were able to reduce injectable G-CSF therapy in participants also treated with mavorixafor, while maintaining mean ANC levels within the normal range. A sub-study also indicated that the mean percentage of functional circulating neutrophils in representative CN study participants remained comparable to that of healthy donors after six months of mavorixafor dosing.
Progress of Phase 3 Trial
X4 Pharmaceuticals is actively enrolling participants in its global, pivotal Phase 3 clinical trial (NCT06056297), known as the 4WARD trial. This trial is designed to evaluate the efficacy, safety, and tolerability of oral, once-daily mavorixafor (with or without stable doses of G-CSF) in individuals with congenital, acquired primary autoimmune, or idiopathic CN. The company anticipates completing enrollment in the 4WARD trial by mid-2025.
XOLREMDI® Launch and WHIM Syndrome
Following the U.S. approval of XOLREMDI (mavorixafor) in April 2024 for WHIM syndrome, X4 Pharmaceuticals has initiated its U.S. launch. The company is also preparing to submit a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) for the approval of mavorixafor in WHIM syndrome by early 2025.
Financial Position
As of September 30, 2024, X4 Pharmaceuticals reported $135.8 million in cash, cash equivalents, restricted cash, and short-term marketable securities. The company believes these funds will support operations into late 2025, not including potential future XOLREMDI revenue.
About Mavorixafor
Mavorixafor is an orally-administered, selective CXCR4 antagonist. It works by blocking the CXCR4 receptor, which plays a key role in the movement of white blood cells between the bone marrow and the bloodstream. By inhibiting CXCR4, mavorixafor helps to mobilize neutrophils from the bone marrow into the peripheral blood, increasing the number of circulating mature neutrophils and lymphocytes.
About Chronic Neutropenia
Chronic neutropenia is characterized by abnormally low levels of neutrophils in the blood, increasing the risk of infections. Mavorixafor aims to address this by mobilizing neutrophils from the bone marrow into the peripheral blood, thereby increasing the ANC and reducing the risk of infections.
