X4 Pharmaceuticals (XFOR) updated investors on its lead drug mavorixafor at the Wells Fargo 21st Annual Healthcare Conference on September 10, 2026, presenting a reconfigured Phase III trial program that the company says preserves statistical rigor while improving execution risk.
The 4WARD study, which evaluates mavorixafor—a CXCR4 antagonist—for chronic neutropenia, will enroll 126 patients, down from an earlier larger design. Executive Chairman Adam Craig said the company consulted statisticians as the year progressed and concluded the revised sample could still answer whether the drug works in its intended population.
The reduction lowered statistical power for the infection endpoint to 88%, from over 96%, and for the absolute neutrophil count (ANC) endpoint to 93%, also from over 96%. Craig noted the team expects to enroll slightly more than 126 patients given a typical end-of-trial uptick.
Protocol requirements call for an ANC below 1,000 and two infections in the prior year. The trial is observing a median ANC in the low 400s, with 75% of patients reporting three or more infections in the previous 12 months. Idiopathic chronic neutropenia accounts for roughly half of the enrolled population, and the median age is 30. About 60% of patients are on G-CSF therapy versus 40% not.
Phase II data showed approximately a 70% overall reduction in G-CSF use, with three patients discontinuing it entirely. The modeled improvement in infection rate translates to roughly a one-third reduction.
Craig confirmed the company recently switched contract research organizations due to prior issues and installed Parexel, saying enrollment is now strong and target completion is expected by end of 2024. The 52-week follow-up for the last patient is projected by end of 2025, with top-line data anticipated eight to 12 weeks later—in early 2026.
X4 also disclosed a separate open-label G-CSF titration study enrolling patients stable on G-CSF, with planned dose reductions every four weeks over approximately 20 weeks.
On the commercial front, Craig estimated the addressable U.S. market at about 15,000 patients meeting the trial's ANC and infection-history criteria. Roughly 80% are treated in community practices, 20% in academic centers. The company plans to target 2,000 to 2,500 hematologists with a U.S. sales force of 50 to 60 representatives and five to six regional business managers.
Mavorixafor for chronic neutropenia is priced at an estimated $200,000 to $300,000 annually on a 400 mg once-daily dose. A cited price for the WHIM indication was around $500,000 annually.
The company has a $359.9 million market capitalization. It reported $15.85 million in revenue over the trailing twelve months with an 81.51% gross profit margin and a current ratio of 11.3. Analyst price targets range from $10 to $13 per share.
Launch planning budget is set for 2028, with Craig citing a potential approval timeline of late 2028 or early 2029 depending on review pacing and priority-review designation. The company stated it is funded through 2029.
