NATIONAL HARBOR, Md.—An investigational iron-based phosphate binder is effective and well tolerated in hemodialysis (HD) patients with hyperphosphatemia, according to data presented at the National Kidney Foundation 2012 Spring Clinical Meetings.
Michel Chonchol, MD, of the University of Colorado Health Sciences Center in Denver, and colleagues tested the drug PA21 in a randomized, open-label phase 2 trial. In the trial, which compared PA21 with sevelamer hydrochloride, 152 HD patients received a fixed-dose regimen of either PA21 (1.25, 5.0, 7.5, 10.0, or 12.5 g/day) or sevelamer (4.8 g/day) for six weeks.
PA21 dosages of 5.0, 7.5, 10.0, and 12.5 g/day reduced serum phosphorus in a dose-dependent manner. The 5.0 and 7.5 g/day dosages had similar efficacy to sevelamer, whereas the two higher doses of PA21 had greater efficacy. The 5.0 and 7.5 g/day dosages decreased serum phosphorus levels from baseline by a mean of 1.64 and 1.26 mg/dL, respectively, versus a mean 1.47 mg/dL decrease for sevelamer.
The mean decrease in serum phosphorus with the 10.0 and 12.5 g/day dosages of PA21 was 1.86 and 1.87 mg/dL, respectively.
All PA21 doses were well tolerated. Except for hypophosphatemia, the researchers observe no dose-dependent association between PA21 and adverse events. The incidence of hypophosphatemia was greater in the two highest PA21 dose groups (30.8% and 30.4% with 10.0 and 12.5 g/day) than in the 5.0 and 7.5 g/day dose groups (15.4% and and 8.0%, respectively).
In addition, the overall incidence of gastrointestinal AEs was similar for PA21 and sevelamer (23.0% and 23.1%).
The data were presented in poster format at the meeting by investigator James A. Tumlin, MD, of the University of Tennessee College of Medicine in Chattanooga.