5610357 REDUCTION IN BLOOD TRANSFUSION BURDEN FOLLOWING INITIATION OF VOXELOTOR OR CRIZANLIZUMAB: A CASE SERIES

Abstract

Background: Patients with sickle cell disease (SCD) often require blood transfusions. While transfusions may improve disease complications, resultant iron overload can lead to end-organ damage. Other transfusion complications include forming of alloantibodies and transmission of infection. Crizanlizumab and voxelotor have been shown respectively to reduce the frequency of vasoocclusive crises (VOCs) and improve anemia. This case series describes 5 patients with SCD who had a clinically significant decrease in transfusion burden following initiation of these therapies. Cases: Patient A is a 63-year-old woman with HbSBeta+thal and avascular necrosis (AVN) who was on intermittent erythrocytapheresis (apheresis) for symptomatic anemia and developed iron overload. Her serum ferritin was elevated despite chelation therapy. Upon initiation of voxelotor, the frequency of apheresis was reduced. She had a sustained improvement in her baseline hemoglobin (hgb) level as well as symptoms of anemia. Her ferritin decreased from 1253 to 714 ng/mL within 5 months and iron chelation therapy was discontinued. She had no change in acute care visits for VOCs (Table 1). Patient B is a 52-year-old woman with Hb SS, AVN and chronic pain who received intermittent simple transfusions for symptomatic anemia requiring 5 units of blood in the 12-months preceding initiation of voxelotor. She did not require any transfusions in the 12-month period following start of voxelotor. Hydroxyurea was discontinued once voxelotor was initiated due to antecedent myelosuppression at doses greater than 200mg. She had a sustained improvement in hgb as well as symptoms of anemia. She had a slight increase in acute care visits for VOCs (Table 1). Patient C is a 48-year-old man with Hb SS and retinopathy who was on monthly apheresis for many years to prevent VOCs. He had iron overload but declined iron chelation. To offset the transfusion associated iron overload, he opted to discontinue apheresis in favor of initiation of voxelotor and reinitiate hydroxyurea which had previously been discontinued. Following cessation of transfusions, he had a sustained improvement in hgb and no change in acute care visits for VOCs (Table 1). His port, placed solely for apheresis, was removed. His serum ferritin decreased from 2913 to 161 ng/mL in 18 months. Patient D is a 30-year-old man with Hb SS, AVN, chronic pain, and priapism who was on monthly apheresis for many years to prevent VOCs. He developed iron overload, however had poor compliance with chelation. After initiation of crizanlizumab for VOC prevention, the number of units utilized for apheresis was gradually tapered. Despite this, his hgb remained stable, he had no change in acute care visits for VOCs (Table 1) and reported an improvement in priapism frequency. Patient E is a 42-year-old woman with Hb SC, retinopathy, AVN, and chronic pain who received monthly apheresis for prevention of VOCs. Crizanlizumab was added for VOC prevention. She had sporadic childcare available, thus she missed some of her apheresis sessions. Despite this inadvertent decrease in transfusions, her hgb remained stable, and she had a decrease in acute care visits for VOCs (Table 1). Conclusion: In SCD patients who receive frequent simple or exchange blood transfusions for indications other than stroke prevention, tapering the amount of blood administered is possible, and should be considered when these patients are treated with crizanlizumab or voxelotor.