Allergy to cabazitaxel: Cross-reactivity between taxanes.

A 46-year-old man, with HIV infection A2 stage and chronic C hepatitis was diagnosed with stage 4 prostate cancer with bone metastases in September 2019. His treatment was started with docetaxel, receiving five cycles with good tolerance, after which he received hormonal treatment. Currently, he presents progression of the disease and docetaxel is reintroduced. After infusing the first 5 mL, he showed respiratory distress with thoracic pain and low oxygen saturation (88%) together with lumbar pain. Both tryptase and interleukin 6 (IL-6) levels in blood were measured at the time of the reaction, and were elevated. The case was discussed in an oncology clinical round, and it was decided a change to cabazitaxel. Allergy tests were performed, including skin prick and intradermal tests, with docetaxel and cabazitaxel. A positive result to intradermal test with docetaxel, 10 mg/mL, was obtained 24 h later. Then 48 h later, another positive intradermal test reaction with 1-mg/mL docetaxel as skin ulceration was reported. However, skin prick and intradermal tests with cabazitaxel were negative.Drug provocation test with cabazitaxel was subsequently performed. After the infusion of 11 mL, the patient presented pharyngeal obstruction with dyspnoea, facial erythema, genital pruritus, and cervical pain that required treatment with intramuscular epinephrine. The results of the allergy study were not concordant with clinical presentation and confirmed the poor predictive value of taxane skin tests.