X4 Pharmaceuticals plans Phase 2b mavorixafor trial in chronic neutropenia for Q1 2027
XFOR•X4 Pharmaceuticals expects enrollment in its planned Phase 2b 4STEPS trial to begin in the first quarter of 2027. The company outlined a 15,000-patient U.S. market opportunity, potentially expanding to 30,000 subject to FDA labeling.
1. Trial plans and timeline
The planned Phase 2b 4STEPS trial will evaluate reducing G-CSF dosing with mavorixafor, with enrollment expected to begin in the first quarter of 2027. X4 Pharmaceuticals said its Phase 3 4WARD trial remains on track to complete target enrollment of 126 participants in the fourth quarter of 2026. Topline results from both trials are expected in the first quarter of 2028.
2. Market opportunity
X4 Pharmaceuticals outlined a 15,000-patient U.S. market opportunity for mavorixafor in primary chronic neutropenia, potentially expanding to 30,000 patients subject to FDA labeling. Positive 4WARD results could support a regulatory submission, with potential FDA approval in late 2028 or early 2029.
