Successful desensitization to bosutinib in chronic myeloid leukemia.

Hypersensitivity reactions (HSRs) to antineoplastic agents may compromise optimal cancer treatment and lead to drug discontinuation. Although tyrosine kinase inhibitors (TKIs) are generally well tolerated, HSRs can occur, and standardized diagnostic and desensitization strategies are lacking. We report a 69-year-old woman with chronic myeloid leukemia who developed facial and oropharyngeal angioedema nine days after starting bosutinib. Symptoms resolved after drug withdrawal, with no alternative trigger identified. As no other TKIs were tolerated and continued therapy was essential for disease control, a rapid drug desensitization protocol was designed. A 14-step, single-day inpatient protocol with incremental dosing was completed without adverse reactions. Bosutinib was then reintroduced through short stepwise dose escalation and maintained at the full therapeutic dose. After one year, the patient remains asymptomatic, without recurrence of angioedema, and with sustained hematologic control. This is the first published desensitization protocol for bosutinib, enabling continuation of first-line therapy.