BOSTON, Nov. 29, 2022 - X4 Pharmaceuticals (Nasdaq: XFOR), a leader in the discovery and development of novel small-molecule therapeutics to benefit people with diseases of the immune system, today announced positive top-line results from the global, pivotal Phase 3 clinical trial (4WHIM) of its lead investigational therapy, mavorixafor, a novel CXCR4 antagonist, in people with WHIM syndrome.
Key Top-Line 4WHIM Trial Results:
- 4WHIM met its primary endpoint, with mavorixafor achieving clinical and statistical superiority over placebo when measuring the length of time that participants’ absolute neutrophil counts (ANC) remained above a clinically meaningful threshold throughout the 52-week trial.
- 4WHIM also met a key secondary endpoint, with mavorixafor achieving clinical and statistical superiority over placebo when measuring the length of time that participants’ absolute lymphocyte counts (ALC) remained above a clinically meaningful threshold throughout the 52-week trial.
- Increases were maintained versus placebo and baseline across 52 weeks, demonstrating durability of treatment effect during the trial.
- Mavorixafor was generally well tolerated in the trial, with no treatment-related serious adverse events reported and no discontinuations for safety events.
- Following completion of the placebo-controlled portion of the trial, more than 90% of the eligible participants opted to receive treatment with mavorixafor in the open-label trial extension.
- Additional data review and analysis of the secondary and exploratory endpoints of the 4WHIM trial are ongoing, with plans to present detailed results at a future medical meeting.
“Mavorixafor is the first and only oral investigational therapy to demonstrate durable improvements in severe chronic neutropenia and lymphopenia, the hallmarks of WHIM syndrome,” said Murray Stewart, DM FRCP, X4’s interim Chief Medical Officer. “Following achievement of these key trial endpoints, we are now preparing to meet with U.S. regulatory authorities in the first half of 2023 to discuss next steps in advancing mavorixafor further towards a submission for regulatory approval and commercialization as the potential first treatment for people with WHIM syndrome.”