SO050DIFFERENT FERRIC CITRATE DOSE REGIMENS IN THE TREATMENT OF IRON DEFICIENCY ANAEMIA IN PATIENTS WITH NON-DIALYSIS-DEPENDENT CKD: THE COMPASS TRIAL
Authors: Pergola Pablo , Belo Diogo , Crawford Paul , Moustafa Moustafa , Vargo Dennis , Luo Wenli , Goldfarb-Rumyantezev Alexander 
Published: June 2020

Abstract

Background and Aims
Ferric citrate (FC) is approved in the US as oral iron replacement for the treatment of iron deficiency anaemia (IDA) in adult patients with non-dialysis dependent (NDD) chronic kidney disease (CKD) and for the treatment of hyperphosphatemia in adult patients with dialysis dependent CKD. For IDA, a starting dose FC of 1 tablet three times daily (TID) is recommended with titration to maintain haemoglobin (Hb) at goal. This study was designed to investigate the possibility of dosing FC twice daily (BID) for flexibility in clinical practice. The efficacy and safety of different FC dosing regimens for the treatment of IDA were examined in adults with NDD-CKD.

Method
In this 48-wk, Phase 4, randomized, open-label, multicentre study, subjects with IDA of NDD-CKD (stage 3-5) were randomized 1:1 to receive 1 FC tablet (1gm containing 210mg ferric iron) TID or 2 tablets BID. At wk 12, subjects whose Hb increased &lt;0.5 g/dL from baseline (BL) or was &lt;10 g/dL had their dose increased to either 2 tablets TID or 3 tablets BID consistent with their original dosing regimen. This prespecified analysis reports data through wk 24. The primary endpoint was mean change in Hb from BL to wk 24. Secondary endpoints included mean change in transferrin saturation (TSAT), ferritin, and phosphate to wk 24.

Results
206 subjects were randomized, 183 were included in this analysis after completing the 24-wk dose titration period. Groups were well matched with mean age of 69.5 +/- 10.32 years, 64% female and 54% had diabetes as a cause of CKD. Mean BL eGFR was 33.6 +/- 10.85 ml/min/1.73m2 and Hb 10.45 +/-0.744 g/dL. In subjects who did not require an increase in the FC dose at wk 12, mean changes in Hb at wk 24 were 1.05 and 1.24 g/dL in the 1 tablet TID and 2 tablet BID dosage groups, respectively. In subjects who required an increase in the FC dose at wk 12, mean changes in Hb at wk 24 were 0.41 and 0.13 g/dL in the 2 tablet TID and 3 tablet BID groups, respectively. Mean changes in TSAT, ferritin and phosphate are presented in the Table. The incidence of TEAEs was 78.2% and 75.0% in the BID and TID groups, respectively. The most common AEs reported were diarrhoea, stool discoloration and constipation. The incidence of SAEs was 13.9% and 17.3% in the BID and TID groups, respectively. Five deaths were reported, none were deemed related to FC per the investigator.

Conclusion
FC was effective and generally well tolerated in the treatment of IDA in this NDD-CKD population. Subjects who had per protocol FC dose increases at wk 12 had less pronounced iron deficiency at BL and smaller increases in Hb suggesting an additional underlying cause of anaemia. Mean changes in Hb, TSAT, ferritin, and phosphate and AE profiles were similar in the BID and TID regimens as well as in 3 g/day and 4 g/day dosing groups supporting the potential for dosing flexibility with FC.
Clinicaltrials.gov identifier NCT03236246
Funding provided by Akebia Therapeutics, Inc.