Intravenous Ferumoxytol Compared With Oral Ferrous Sulfate for Iron Deficiency Anemia in Pregnancy: A Randomized Controlled Trial.

OBJECTIVE

To evaluate the comparative effectiveness of intravenous (IV) ferumoxytol compared with oral ferrous sulfate for increasing hemoglobin levels in the treatment of iron deficiency anemia (IDA) in pregnancy.

METHODS

We conducted an open-label randomized controlled trial to compare oral ferrous sulfate with IV ferumoxytol for the treatment of IDA in pregnancy. Pregnant women with IDA (ferritin less than 30 ng/dL or transferrin saturation less than 20% and hemoglobin less than 11 g/dL) at 24-34 weeks of gestation were eligible; patients with hereditary anemias or malabsorptive disorders were excluded. Patients were computer block randomized to IV ferumoxytol (510 mg for hemoglobin 9.0-10.9 g/dL or 1,020 mg for hemoglobin 7.0-8.9 g/dL) or oral ferrous sulfate every other day (325 mg for hemoglobin 9.0-10.9 g/dL or 650 mg for hemoglobin 7.0-8.9 g/dL). The primary outcome was the change in hemoglobin from treatment initiation to week 4 postinitiation. We estimated that 80 patients were needed, assuming an effect size of 1.0 g/dL, 90% power, 5% type I error rate, and 20% drop-out rate. Secondary outcomes included change in hemoglobin by 8 weeks, anemia resolution, and postpartum hemoglobin. Intention-to-treat analyses were conducted using Wilcoxon rank sum and Fisher exact tests.

RESULTS

Of the 80 randomized patients, 40 were assigned to oral ferrous sulfate and 40 to IV ferumoxytol. Treatment with IV ferumoxytol resulted in a greater change in hemoglobin at 4 weeks than oral ferrous sulfate (median [Q1-Q3] 1.10 g/dL [0.70-1.70] vs 0.40 g/dL [-0.10 to 0.80], P <.001). Treatment with IV ferumoxytol also resulted in a larger hemoglobin increase at 8 weeks (median [Q1-Q3] 1.80 g/dL [1.20-2.10] vs 0.70 g/dL [0.20-1.20], P <.001), resolution of anemia (37/40 [92.5%] vs 26/40 [65.0%], P =.005), and higher postpartum hemoglobin (median [Q1-Q3] 10.25 g/dL [9.28-10.90] vs 9.65 [8.85-10.05]).

CONCLUSION

Treatment of IDA during pregnancy with IV ferumoxytol improved hemoglobin at delivery and reduced the prevalence of anemia to a greater extent than oral ferrous sulfate.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT04253626.