Update (June 24, 2026): BENRIC Trial — Benazepril Reduced Proteinuria but Not Overall Survival in Feline CKD

Bottom line.

• The landmark BENRIC trial — a double-blind, placebo-controlled randomized study in 192 cats with CKD (plasma creatinine ≥ 2 mg/dL) — showed that benazepril produced a significant reduction in proteinuria (UPC, P = .005) but did not improve overall renal survival time (mean 637 ± 480 days benazepril vs 520 ± 323 days placebo; P = .47).¹
• In the subgroup of 13 cats with initial UPC ≥ 1, benazepril-treated cats had numerically longer renal survival (402 ± 202 vs 149 ± 90 days) and significantly better appetite (P = .017), though the survival difference was not statistically significant (P = .27).¹
• Benazepril was well tolerated across a treatment period of up to 1,119 days; no clinically relevant safety concerns differentiated it from placebo.¹
• This is a clinician-facing evidence summary. It is not a dosing protocol; confirm regimen, monitoring and contraindications against current product labeling and a veterinary formulary.

Drug facts

• Class: Angiotensin-converting enzyme (ACE) inhibitor; prodrug converted to active benazeprilat.¹
• Mechanism: Inhibits ACE, reducing angiotensin II formation, lowering systemic and glomerular blood pressure and reducing proteinuria; blocks both AT1 and AT2 angiotensin receptor downstream signalling.¹
• Route/interval: Oral, once daily in the BENRIC trial (defer specific dose to current labeling and formulary).¹
• Indication discussed here: CKD in cats — specifically the antiproteinuric effect and the evidence base for and against survival benefit.¹
• Key trial population: Cats with plasma creatinine ≥ 2 mg/dL and urine specific gravity ≤ 1.025; most cats fed a low-phosphate/protein/sodium diet throughout the trial.¹

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What the evidence shows

The BENRIC trial design and population

The Benazepril in Renal Insufficiency in Cats (BENRIC) trial was a double-blind, parallel-group, prospective, randomized placebo-controlled study.¹ A total of 192 cats with naturally occurring CKD (plasma creatinine ≥ 2 mg/dL [≥177 μmol/L], urine specific gravity ≤ 1.025) were enrolled and received daily oral placebo (n = 96) or benazepril-HCl at 0.5–1.0 mg/kg (n = 96) for up to 1,119 days. Most cats were fed exclusively a diet low in phosphate, protein and sodium throughout.

Proteinuria outcomes

Benazepril produced a significant reduction in proteinuria assessed by the urine protein-to-creatinine ratio (UPC; P = .005).¹ This antiproteinuric effect was present across all subgroups tested, including cats with UPC < 0.2, though it was largest in cats with higher baseline UPCs. Plasma protein concentrations were maintained at higher levels with benazepril than with placebo during treatment in cats with initial UPC < 1 (P = .038).¹

Survival outcomes

There was no statistically significant difference in renal survival time between the two groups when all 192 cats were compared: mean ± SD renal survival times were 637 ± 480 days with benazepril and 520 ± 323 days with placebo (P = .47).¹

In the 13 cats with initial UPC ≥ 1, mean renal survival times were 402 ± 202 days with benazepril and 149 ± 90 days with placebo (P = .27); the difference was not statistically significant, likely due to the small subgroup size.¹ Cats in this high-proteinuria subgroup treated with benazepril also had significantly better appetite (P = .017) compared with placebo-treated cats.¹

Tolerability

Benazepril was well tolerated over a treatment period extending to 1,119 days, with no clinically important safety differences between active treatment and placebo.¹

How this fits clinical practice

The BENRIC trial confirms that benazepril significantly reduces proteinuria in cats with CKD — a meaningful intermediate endpoint given that proteinuria correlates with shorter survival. The independent prognostic significance of proteinuria severity in feline CKD has been formally demonstrated: cats with UP/C 0.2–0.4 had a hazard ratio for death or euthanasia of 2.9 (95% CI 1.4–6.3) and cats with UP/C > 0.4 had a hazard ratio of 4.0 (95% CI 2.0–8.0), compared with cats with UP/C < 0.2, supporting proteinuria reduction as a clinically meaningful target.² However, the trial did not demonstrate a statistically significant overall survival advantage, which distinguishes feline data from analogous human RAAS-blockade trials in proteinuric nephropathy.¹ Clinically, the implication is that benazepril remains a reasonable antiproteinuric agent, particularly in proteinuric cats where telmisartan is unavailable or contraindicated; the greatest potential benefit appears to be in cats with higher baseline UPC. Monitoring should include serial UPC, creatinine, electrolytes and body weight; a recheck 2–4 weeks after initiation is appropriate. Do not infer specific doses from this summary.

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References

1. King JN, Gunn-Moore DA, Tasker S, Gleadhill A, Strehlau G; BENRIC Study Group. 2006. Tolerability and Efficacy of Benazepril in Cats with Chronic Kidney Disease. J Vet Intern Med 20(5):1054-1064. https://academic.oup.com/jvim/article/20/5/1054/8450476
2. Syme HM, Markwell PJ, Pfeiffer D, Elliott J. 2006. Survival of Cats with Naturally Occurring Chronic Renal Failure Is Related to Severity of Proteinuria. J Vet Intern Med 20(3):528-535. https://pubmed.ncbi.nlm.nih.gov/16734085/

Changelog

• 2026-06-24: First published.