Outpatient rapid drug desensitisation for chemotherapy and biologic agents: high success rates in a large single-centre cohort study

OBJECTIVES: We evaluated rapid drug desensitisation (RDD) protocols at Memorial Sloan Kettering Cancer Center (MSK) to determine completion rates and characterise hypersensitivity reaction (HSR) phenotypes using clinical features and biomarker data. This study addresses an important gap by assessing an expanded range of antineoplastic agents, incorporating biomarkers such as tryptase and interleukin-6, and evaluating outcomes under updated outpatient oncology and allergy-co-managed desensitisation pathways. METHODS: This retrospective, single-centre descriptive study included adult patients who underwent RDD to any chemotherapeutic or biologic agent between 1 October 2023 and 31 October 2024, following a documented HSR. RDD 'success' was defined as completion of at least one cycle without treatment discontinuation due to breakthrough HSR. This definition reflects MSK's current clinical decision-making approach. RESULTS: A total of 142 patients met inclusion criteria. The median age was 62 years and 103 (73%) were female. Overall RDD success was 92.3%, (131 patients). Breakthrough HSRs occurred in 23% of patients and 19 patients (13.4%) subsequently discontinued the agent. Biomarker-based phenotyping was feasible in 26 patients; incomplete sampling due to workflow limitations precluded classification in the remaining cases. CONCLUSIONS: MSK's outpatient RDD protocols demonstrate consistently high success rates across a broad spectrum of chemotherapy and biologic agents, exceeding earlier institutional experience. Increased interdisciplinary collaboration, expanding institutional expertise and refined protocol tailoring represent key advances. Future work should prioritise biomarker-driven approaches and standardised workflows to support consistent biomarker collection, thereby improving phenotype classification and enhancing mechanistic insight to guide individualised desensitisation strategies.