Efficacy and Safety of Lantharenol® on Phosphorus Metabolism in Cats with Chronic Kidney Disease
ACVIM 2008
B.H. Schmidt1; U. Spiecker-Hauser1; M. Murphy2
1Bayer Healthcare AG, Monheim, Germany; 2Charles River Laboratories, Ballina, Ireland

The objective of this study was to assess the efficacy and safety of Lantharenol®, a novel intestinal phosphate binder, in cats with renal impairment.

There was a single study group consisting of ten cats (6 male and 4 female cats) that had successfully undergone a two-stage partial renal ablation procedure. The cats were normophosphataemic and clinically normal except for the renal impairment. Each animal was individually housed and offered Lantharenol®once daily mixed with wet cat feed at the following concentrations: 0-0.3-1.0-3.0-0 g Lantharenol® kg-1 feed original substance, each dose being administered for two weeks. During the last three days of each dose period, urine and feces were quantitatively collected from each animal, and the quantity of diet consumed was measured. Quantitative P excretion in urine and feces, and the derived apparent digestibility and intestinal absorption of P served as efficacy parameters. Renal function was assessed by monitoring urea, creatinine, calcium and inorganic P levels in serum as well as specific gravity and creatinine levels in urine. Safety was determined by measuring the P balance as well as feed intake and body weight, repeated health status examinations and the observation of the daily tolerance of Lantharenol®.

Lantharenol® was well accepted, tolerated and effective as an intestinal phosphate binder in the dose range of 0.3 to 3 g kg-1 wet feed. In the specific feed used for the present study, this range corresponded to 1.77 to 17.7 g kg-1 complete feed. The highest dose tested mediated the greatest reduction in absorption and apparent digestibility of P, along with a significant increase in fecal P excretion. The concomitant decrease in P balance is explained by an increase in urinary P excretion in Lantharenol®-treated animals. Renal function and the defined safety parameters were not compromised in any manner potentially related to test item administration.

In conclusion, feed supplementation with Lantharenol® results in a safe, dose-dependent, statistically significant and clinically relevant reduction of P availability, thus ending up in a relief of kidney burden to excrete excess P. Longer-term studies will be required to assess potential effects on serum inorganic P levels especially in chronic kidney disease patients afflicted with hyperphosphataemia.

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Bernard Schmidt