The ongoing clinical trial comparing plerixafor to G-CSF for WHIM syndrome could significantly alter treatment paradigms in this rare disease space. A successful outcome may lead to increased competition and necessitate strategic shifts for companies involved in rare disease therapies. Regulatory context from FDA (FDA AP — PROMETHAZINE HYDROCHLORIDE AND DEXTROMETHORPHAN HYDROBROMIDE (ORIG)) supports the near-term read. Assessment grounded in 8 ranked evidence items (8 high-relevance).