David Dale, MD, University of Washington, Seattle, WA, comments on 4WHIM, a Phase II trial that investigates the use of mavorixafor (NCT03005327), an antagonist to the receptor whose mutation causes WHIM disease. This experimental approach seeks to replace the current treatment based on antibiotics and cytokines. This interview took place at the European Hematology Association (EHA) Congress 2022 held in Vienna, Austria.