RESUMEN
We present the case of a patient with failed desensitisation to paclitaxel that was ultimately successful with omalizumab treatment. Our patient, a female aged between 20-25 and diagnosed with a triple negative breast cancer, received first-line treatment with carboplatin and paclitaxel. During the second cycle of paclitaxel, she experienced heat, dyspnoea, facial angioedema and vomiting. Skin tests for allergic reactions returned negative results, and drug provocation tests showed a positive result (anaphylaxis). Rapid drug desensitisation (RDD) was carried out with two bags of dilutions but at the beginning of the infusion, the patient experienced symptoms again, so the infusion was stopped. Therefore, the use of omalizumab, already reported as a successful adjuvant in desensitisation to other drugs, was considered. The anti-immunoglobulin E (IgE) monoclonal antibody was administered off-label before the first programmed desensitisation with success: total dose of paclitaxel was infused without any reaction. The patient was able to receive the complete chemotherapy treatment.