Successful Desensitization to Irinotecan in a Patient with Metastatic Esophageal Squamous Cell Carcinoma and a History of Anaphylaxis in Response to Irinotecan-Case Report and Literature Review

Background: Irinotecan is a topoisomerase I inhibitor used for the treatment of various cancers, such as gastrointestinal, pancreatic, pulmonary, ovarian, and cervical cancers. Among chemotherapy agents, it represents a rare trigger of drug hypersensitivity reactions, with few cases being reported until today. Methods: We present the case of a patient with metastatic esophageal cancer and a history of irinotecan-induced grade IV (WAO classification) anaphylaxis. An IgE-mediated reaction was confirmed in our case, as evidenced by a positive intradermal skin test result, and we carried out a successful desensitization protocol, given irinotecan's indispensability in the treatment regimen. Our case underscores the fact that in such situations where the culprit drug is also the only therapeutic option available for such a patient, implementing a desensitization protocol may represent the only viable approach to ensure safe and successful dosing. Results: A comprehensive review of the literature was also conducted to assess previously reported irinotecan-induced hypersensitivity reactions, the utility of skin tests in identifying sensitisation to irinotecan, and the existing desensitization protocols. We found a total of seventeen cases of hypersensitivity reactions to irinotecan in the literature, out of which four provided the skin test results obtained and six performed desensitization protocols for irinotecan. Conclusions: Our literature review highlights that skin testing and desensitization protocols can provide suitable solutions for managing hypersensitivity reactions to irinotecan.