X4 Pharmaceuticals (XFOR) Morgan Stanley 22nd Annual Global Healthcare Conference summary

Key achievements and product updates

• Achieved first drug approval for Xolremdi in WHIM syndrome, a rare immunodeficiency, and reported strong phase II data for a broader indication in chronic neutropenia (CN).

• Xolremdi is the first oral, once-daily CXCR4 antagonist, enabling white blood cell migration from bone marrow to circulation, reducing infection rates and severity.

• Phase III data in WHIM showed a 60% reduction in infection rate and significant decrease in illness duration.

• U.S. launch underway with a specialized sales force and support infrastructure; European MAA submission planned for early 2025.

• Patent protection for mavorixafor extends through 2038, with robust IP strategy in place.

Market landscape and patient impact

• WHIM syndrome affects about 1,000 patients in the U.S., with consistent prevalence globally; Xolremdi is the first targeted therapy addressing the disease's root cause.

• Standard of care is heterogeneous, often involving immunoglobulins and G-CSF, but unmet needs remain due to side effects and limited efficacy.

• Chronic neutropenia represents a larger market, with 50,000 diagnosed U.S. patients; 15,000 have high unmet need due to G-CSF intolerance or refractoriness.

• Mavorixafor shows promise as a safer, more tolerable alternative or adjunct to G-CSF, with potential to reduce or eliminate G-CSF use.

• Physicians target ANC levels of 800–1,000 for infection risk reduction; phase II and III trials are designed to meet these clinical goals.

Clinical development and future plans

• Phase II CN trial explores mavorixafor as monotherapy and in combination with G-CSF; data show sustained neutrophil increases and potential to reduce G-CSF.

• Phase III CN trial is a randomized, placebo-controlled, double-blind study targeting high unmet need patients, with enrollment expected to complete by mid-2025 and data in the second half of 2026.

• No interim readout planned; final data will inform broader market potential.

• European regulatory engagement is ongoing, with MAA submission on track and similar prevalence expected as in the U.S.

• Financial strategy includes seeking ex-U.S. partnerships, non-dilutive funding, and careful capital allocation to support ongoing launches and trials.