D2.399 - Successful Deferasirox Desensitization in a Patient with Delayed-Type Hypersensitivity

Introduction

Deferasirox is an oral iron chelator used to treat iron overload and is, in routine clinical use, frequently preferred in thalassemia and sickle cell disease; however, it may, albeit rarely, trigger delayed-type hypersensitivity. When other iron chelators cannot be administered because of limited efficacy or poor tolerability, desensitization can permit the safe reintroduction of deferasirox. We report a deferasirox desensitization protocol applied in a pediatric patient who developed a delayed-type reaction and had restricted alternative treatment options.

Case Presentation

An 8-year-old girl followed in a pediatric hematology outpatient clinic for alpha-thalassemia (hemoglobin H disease) underwent annual cardiac screening with T2* MRI, which demonstrated myocardial iron deposition. A serum ferritin level >500 ng/mL, non–transfusion-related iron accumulation, cardiac involvement, and a hereditary hemochromatosis gene mutation indicated chelation therapy. Deferasirox was selected for ease of use and reduction of cardiac iron burden. On day 7, pruritic erythematous eruptions developed on the palms, periumbilical region, ankles, soles, and medial legs; the next day, diffuse abdominal pain accompanied pruritus. No other systemic symptoms were reported. Cetirizine was initiated, and deferasirox was discontinued 2 days after symptom onset; lesions regressed within the subsequent 2 days. Her history included asthma, allergic rhinitis, and atopic dermatitis, with sensitization to house dust mite. There were no significant features in the family history. Physical examination was otherwise unremarkable except for splenomegaly. Skin testing for deferasirox was not performed because antihistamine treatment was ongoing. Because deferasirox was considered necessary and alternatives were limited, desensitization was planned. The patient was hospitalized, and a published pediatric protocol was adapted: the starting dose was 1/200 of the target dose (10 mg/kg), with dose increases every 2–3 days. The protocol was completed over 18 days (Table 1); no reactions occurred, and the target dose was tolerated without incident.

Conclusion

Individualized desensitization protocols may enable continued deferasirox use in patients with delayed-type hypersensitivity when alternative therapies are limited. This case supports stepwise dose escalation as an effective, well-tolerated strategy. Multidisciplinary care, close monitoring, and prompt management of potential adverse effects are critical determinants of protocol success.