Background: Imatinib mesylate is a tyrosine kinase inhibitor used for the treatment of chronic myeloid leukemia and hypereosinophilic syndrome. Imatinib is associated with a variety of adverse cutaneous reactions, including urticaria, maculopapular exanthem, generalized exanthematous pustulosis, exfoliative dermatitis, and Stevens-Johnson syndrome.
Objective: To evaluate the safety and efficacy of oral desensitization by administering incremental dosages of imatinib mesylate to patients with leukemia who have had rashes associated with prior exposure.
Methods: Ten patients with leukemia and imatinib-associated recurrent rash underwent a 4-hour outpatient oral desensitization procedure. Beginning with 10 ng, we administered oral imatinib elixir in increasing dosages every 15 minutes. Patient outcomes were monitored by a return clinic visit and by telephone follow-up for a median of approximately 3 years.
Results: No episodes of anaphylaxis or serious adverse effects occurred during or immediately after desensitization. Four patients (all with urticaria) had no recurrence of rash after desensitization, and 4 had recurrent rash that resolved after temporary glucocorticosteroid and antihistamine administration. Two patients developed a recurrent rash 5 hours and several days after the procedure and were unable to resume therapy.
Conclusion: This oral desensitization protocol appears to help some leukemic patients with recurrent rash tolerate imatinib mesylate, thus permitting continuation of this life-prolonging therapy. These findings suggest that some adverse cutaneous reactions to imatinib may be due to a hypersensitivity mechanism rather than a pharmacologic effect.