Prevalence and management of immediate drug hypersensitivity observed during antineoplastic drug therapy.

Background: Immediate drug hypersensitivity reactions (IDHRs) complicate the treatment of patients with cancer. Rapid drug desensitization (RDD) is not a standard treatment option in Northern Europe as in Southern Europe and the US. Thus, in Denmark, allergists are not involved when cancer treatments are complicated by IDHRs.

Purpose: The purpose was to investigate whether Danish patients could benefit from the implementation of an allergy work-up including RDD by investigating the magnitude of the problem with IDHRs in Danish antineoplastic drug therapy, in addition to describe characteristics of IDHRs, re-treatment strategies, and outcomes.

Patients and methods: This prospective observational single-center study was conducted at a large university hospital. Patients were included over 17 months. Patients were interviewed during index reaction. Information on culprit drug, infusion procedure, and premedication was obtained, together with reaction phenotype and severity. After 3 months, information on re-treatment strategies and outcome were obtained from medical records.

Results: In total, 126 patients experienced IDHRs during the study period. This corresponds to 2.5% of patients receiving antineoplastic drug therapy. Re-treatment, using increased premedication and/or decreased infusion rate, was attempted in 97 patients and tolerated by 69. However, 57 out of 126 patients (45%) discontinued treatment. This corresponds to 1.1% of patients receiving antineoplastic drug therapy. Patients with gynecologic cancers had a particularly high risk.

Interpretation: IDHRs are infrequent in antineoplastic drug therapy, but due to the large number of patients with cancer, the number of IDHRs is significant. Patients discontinuing treatment could benefit from an allergy work-up including RDD.