A Multicenter Single-Arm Study of Switching to Ferric Citrate Hydrate for Iron Deficiency Anemia in Patients Intolerant to Oral Iron: RIO-SWITCH.

Introduction: Treatment interruptions due to adverse drug reactions (ADRs) are common in iron deficiency anemia (IDA). We evaluated medication completion rates and quality of life (QoL) changes in patients with IDA after starting ferric citrate hydrate (FCH) treatment.

Methods: This multicenter, open-label, uncontrolled, single-arm comparative study included 30 Japanese female patients with IDA who experienced nausea and/or vomiting (N/V) with previous oral iron preparations. Patients received FCH 500 mg orally daily (< 1000 mg/day). Those with hemoglobin levels ≥ 11.0 g/dl completed the study at week 4; others continued until week 8. The primary endpoint was medication completion rate. Secondary endpoints included medication compliance rate, treatment satisfaction scores, and QoL scores and changes.

Results: Thirty patients initiated and completed treatment; 24 reached ≥ 11.0 g/dl hemoglobin at week 4 and ended treatment, while 6 continued until week 8. The medication compliance rate was 93.92% ± 8.11% (mean ± standard deviation [SD]), and the completion rate was 100.0% (95% confidence interval 88.4-100.0%). Questionnaire findings revealed that the most severe nausea score decreased from 5.7 ± 2.4 to 1.7 ± 2.1 (mean ± SD), N/V incidence decreased from 100.0 to 63.3%, and patients reporting that N/V did not interfere with daily life increased from 6.7 to 52.6% following the switch to FCH. Twenty-four patients (80.0%) reported a satisfactory experience with FCH versus their previous oral iron preparation. Scores for all eight subscales of the Short-Form 36-Item Health Survey v2 improved, with significant increases in six. Nine ADR events occurred in six patients (20.0%), including nausea in three (10.0%); none were serious or resulted in treatment discontinuation.

Conclusion: FCH treatment exhibited a satisfactory medication completion rate in patients with IDA. Switching to FCH reduced N/V incidence and improved N/V and QoL severity compared with previous oral iron preparations.

Trial Registration: jRCTs031210634. Registration date: March 01, 2022.