Effect of Ferumoxytol Treatment on Secondary Thrombocytosis in Patients With Iron Deficiency Anemia and Inflammatory Bowel Disease

Abstract

Introduction: Iron deficiency anemia (IDA) is common in patients with gastrointestinal (GI) disease due to multiple factors, such as blood loss and malabsorption, and with IBD, exacerbated by inflammation. Secondary thrombocytosis, a consequence of both IDA and inflammation, is a frequent complication of IBD. This subgroup analysis of a randomized, placebo-controlled, double-blind, study explored the impact of treatment with ferumoxytol (FER), an IV iron indicated for the treatment of IDA in adults with chronic kidney disease, on secondary thrombocytosis in patients whose underlying cause of IDA was IBD vs. those with other GI disorders (e.g., gastric bypass, GI bleed). Methods: Patients with a history of unsatisfactory oral iron therapy or in whom oral iron cannot be used, Hgb <10 and >7 g/dL, and TSAT <20% were randomized 3:1 to either 2 injections of 510 mg of FER 5±3 days apart or normal saline (placebo). Measures of hematology and iron status (including: platelets [PLT], Hgb, reticulocyte Hgb content [CHr] (sensitive marker of iron availability), transferrin saturation [TSAT], ferritin) were assessed at baseline and weekly up to week 5. Baseline values were compared between patients whose underlying cause of IDA was IBD vs. other non-inflammatory GI disorders using T-test. Changes from baseline were compared between treatment groups using ANCOVA controlling for baseline values and IBD subgroup. Results: The degree of iron deficiency and anemia was similar in both subgroups at baseline, with no difference in mean Hgb, CHr, TSAT, or ferritin. Consistent with a greater degree of inflammation among IBD patients, their leukocyte count trended higher, and while mean PLT count was elevated in both subgroups, it was significantly higher in the IBD subgroup. Independent of IBD status, mean PLT count decreased significantly more following FER than placebo, with the proportion of patients with PLT>400 decreasing in the FER group from 35% to 10% (p<0.0001, McNemar’s) and remaining unchanged in the placebo group. These changes were accompanied by significantly greater improvement in all markers of iron status with FER than placebo, and no change in leukocyte count in either group. Conclusion: Treatment with IV iron decreased elevated PLT count independent of IBD status or apparent effect on inflammation. Disclosure - Dr Dahl - employee: AMAG Pharmaceuticals, Inc.; Dr Strauss - employee: AMAG Pharmaceuticals, Inc.; Dr Kaper - employee: AMAG Pharmaceuticals, Inc; Ms Bernard employee: AMAG Pharmaceuticals, Inc. This research was supported by an industry grant from AMAG Pharmaceuticals, Inc.Table 1