Safety and Efficacy of Ferumoxytol for the Treatment of Iron Deficiency Anemia in a Community Based Hematology Clinic

Background Although oral iron therapy is often the initial approach for the treatment of iron deficiency anemia (IDA) many patients fail to respond and tolerate. Approved parenteral iron treatment options have inconvenient dosing schedules, safety warnings and require an infusion center. Since the availability of parenteral Ferumoxytol (FER) more and more patients have been treated with this drug in the community setting.

Methods Efficacy and safety data of FER treatment in general IDA population at Saint Francis Cancer Treatment Center, a community based hematology/oncology clinic in Grand Island Nebraska, were analyzed. Patients received one dose, one course (i.e. 2x 510 mg iv 1 week apart) or more than one course of FER. For patients with persistent or recurrent IDA (defined as hemoglobin (Hgb) <11.0 g/dL and transferrin saturation (TSAT) <20%, second or more courses of FER were given. All patients were evaluated for efficacy, safety, number of doses of FER treatment, underlying causes of iron deficiency, presence or absence of Chronic Kidney Disease (CKD), and presence or absence of prior iron therapy. Changes in mean Hgb, MCV, RDW, and TSAT from baseline to week five and comparisons between the groups of patients treated with one or more doses of FER, between the groups of patients with or without CKD, and between the groups of patients with or without prior iron treatment were analyzed. Fisher`s exact test and Wilcoxon 2-way test were used for statistical calculations.

Results A total of 140 patients with IDA treated with FER were identified. Sixty patients had one course and eight patients had more than one course, while seventy-two patients had only one dose of FER. CKD was present in 46 (33%) patients and prior iron therapy was given to 93 (66 %) patients. Underlying causes of IDA were gastrointestinal in 73(52%) patients, genitourinary in 17(12%), gynecological in 14(10%) and were unclear in 36(26%) patients. Overall, 63(45%) patients had more than 2 g/dL increase in Hgb. Mean changes in Hgb, MCV, RDW, and TSAT from baseline to week five were 1.76 g/dL, 5.42 fL, 2.74%, and 10%, respectively. FER treatment increased Hgb (p=0.02) and TSAT (p=0.01) significantly only in CKD patients with prior iron treatment. There were no significant improvements in other settings and other anemia parameters, (Table 1). Adverse events were mild and transient and included nausea, myalgia, headache, dizziness.

Conclusion FER was well tolerated and safe but showed only modest activity in general IDA patients in the community setting. Improvements in IDA parameters did not reach statistical significance between the groups of patients given one versus more doses of the drug and between the groups of patients without CKD with or without prior iron treatment. FER treatment seemed to be effective in raising Hgb and TSAT only in CKD patients with prior iron treatment. Prospective controlled studies of this drug in various IDA settings, dose and frequency are needed to better evaluate and define the optimal use.