A number of processes involved in biologic half-life consumption, degradation and elimination among others (physicians, biochemists, etc please weigh in as time permits).
Monoclonal antibodies are too large to excrete via kidneys. Leronlimab does not undergo hepatic bioconversion and transformation. It blocks CCR5 but does not, to my knowledge, induce receptor internalizations.
Unbound Leronlimab will eventually undergo phagocytosis and degradation by lysosomes.
Monocytes have a half life of ~7 days and once extravasated into macrophages, I believe can survive for more than a month.
Phagocytosis and elimination of macrophages will eliminate attached Leronlimab.
There is undoubtedly additional complexity, but that is my basic understanding.