OBJECTIVES

Inhibitors of the angiotensin-converting enzyme (ACE) have been proven to have beneficial effects in chronic renal insufficiency (CRI) in man. Benazepril has been shown to prolong survival time and reduce proteinuria in a large clinical trial in humans (Maschio et al., 1996) and to have beneficial haemodynamic effects (normalization of glomerular hypertension with maintained or increased glomerular filtration rate) in a model of CRI in cats (Brown et al., 2001). The objective of the current study was to evaluate the efficacy and tolerability of benazepril in clinical cases of CRI in cats.

MATERIALS

The study was a double-blinded, randomised, prospective, parallel-group design, placebo-controlled clinical trial. Inclusion criteria were CRI of renal origin with plasma creatinine greater than or equal to 177 micromol/L and a urine specific gravity less than or equal to 1.025. The cats were randomised to receive benazepril (0.5-1 mg/kg) or a matched placebo once per day for up to 3 years. The cats were re-examined after 7 days and then every 1-3 months. Current results are from an interim assessment made at the mid-point of the trial.

RESULTS

Benazepril produced a significant (p<0.05) reduction in urine protein (UPC). The magnitude of the benefit of benazepril was proportional to the initial UPC, but significant effects were observed in all sub-groups, including cats with low UPC (<0.2). There was no significant difference in survival time for all cats between the two groups, mean (SE) times were 501 (34) for benazepril and 391 (22) for placebo. In the sub-group of cats with UPC>1, benazepril treated cats had longer survival times (401 versus 126 days) and significantly higher survival rate at the end of the trial, quality life and appetite scores.

There were no significant differences in incidences of adverse events or biochemistry or haematology values between the two groups

CONCLUSION

These interim results suggest that benazepril may have beneficial effects in cats with CRI, notably in cases with marked proteinuria, and is well tolerated.

References

1.  Brown SA, Brown CA, Jacobs G, et al. Effects of the angiotensin converting enzyme inhibitor benazepril in cats with induced renal failure. Am J Vet Res 2001; 62: 375-383.

2.  Maschio G, Alberti D, Janin G, et al. Effect of angiotensin-converting enzyme inhibitor benazepril on the progression of chronic renal insufficiency. N Engl J Med 1996; 334: 939-945