5PSQ-046 Analysis of desensitisation protocols used in oncology patients in a tertiary hospital

<h3>Background and Importance</h3> Drug desensitisation helps patients tolerate medications that previously caused allergic reactions. Initially for antibiotics, it is now used for chemotherapy and biologics, improving patient outcomes by allowing continued treatment. Patients receive customised doses through controlled serial dilutions, with premedication given 2 days before and on the day of desensitisation. A prick test checks for allergic reactions if hypersensitivity is suspected. <h3>Aim and Objectives</h3> To describe desensitisation protocols in a tertiary care hospital and test if prick test results for skin allergies relate to immediate anaphylactic reactions during infusions. We also reviewed common adverse events with chemotherapy before desensitisation protocol. <h3>Material and Methods</h3> Retrospective observational study (September 2023 to September 2024) that included all patients requiring a desensitisation protocol during chemotherapy. Qualitative data: sex, diagnosis, death, protocol received, skin allergy test details (drugs analysed and results), symptoms during hypersensitivity reaction, treatment response, whether patients relapsed and need for treatment changes. Quantitative data: age, treatment cycle in which the hypersensitivity reaction occurs, number of desensitisation steps and bags, protocol duration, and number of desensitisation cycles received. <h3>Results</h3> A total of 34 patients were analysed, 79.4% women with a median age of 60 years (IQR 66–53.7). Diagnoses included ovarian (61.7%), endometrial (11.7%), lung (11.7%), prostate (5.8%), breast (2.5%), colorectal (2.2%), Hodgkin’s lymphoma (2.2%), and osteosarcoma (2.2%).Desensitisation protocols were most common for taxanes (44.1%), platinum (35.2%), etoposide (11.7%), gemcitabine (5.8%), and trastuzumab (3.2%). Hypersensitivity reactions typically occurred in the second treatment cycle. An intradermal skin test was performed on 94.1% of patients, with 38.2% testing positive. Patients received a median of five desensitisation cycles and the median treatment duration was 86 days (IQR 177–64.5). Complete response was achieved in 35.2% of patients, while 55.8% required a change in treatment. The most common symptoms during hypersensitivity reactions were erythema/flushing (70.5%), chest pain (70.3%), dyspnoea (23.5%), gastrointestinal issues (23.2%), low back pain (22.8%), cardiovascular disturbances(20.5%), abdominal pain (17.6%), dizziness (14.7%), sweating (11.7%) and pruritus (8.8%). A total of 23.5% of patients died from causes unrelated to hypersensitivity reactions. <h3>Conclusion and Relevance</h3> Chemotherapy desensitisation allows allergic patients to safely undergo treatments through carefully designed protocols and close monitoring. While it does not completely eliminate hypersensitivity risks, it significantly reduces them. Given its substantial benefits, desensitisation should become the standard of care. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest