A Phase III Safety Study of Ferumoxytol Compared to Ferric Carboxymaltose for the Treatment of Iron Deficiency Anemia (IDA)

Key Inclusion Criteria include: * Participants with IDA and in whom IV iron treatment is indicated and defined as: * Participants with documented hemoglobin \<12.0 g per deciliter (dL) for females and \<14.0 g/dL for males within 60 days of dosing And * Participants with documented transferrin saturation (TSAT) ≤20% or Ferritin ≤100 nanograms (ng) per mL within 60 days of dosing * Documented history of unsatisfactory oral iron therapy or in whom oral iron cannot be tolerated, or for whom oral iron is considered medically inappropriate (as per oral iron history questionnaire) * All participants (male and female) of childbearing potential who are sexually active who agree to routinely use adequate contraception from randomization throughout the duration of the study Key Exclusion Criteria include: * Known hypersensitivity reaction to any component of ferumoxytol or FCM * History of allergy to an IV iron * History of multiple drug allergies * Participants with dialysis-dependent chronic kidney disease * Hemoglobin ≤7.0 g/dL * Female participants who are pregnant, intend to become pregnant, are breastfeeding, have a positive serum/urine pregnancy test or not willing to use effective contraceptive precautions during the study (including females of childbearing potential who are partners of male participants)