Robenacoxib Feline Chronic Safety: Pooled 4-Trial Analysis Including CKD Subgroup — King et al. 2021

Bottom line

• A pooled safety analysis by King et al. (J Vet Intern Med 2021) of 4 prospective randomized blinded clinical trials (449 client-owned cats with chronic musculoskeletal disease; robenacoxib n = 222, placebo n = 227; 4–12 weeks' duration) found the relative risk of at least one adverse event was 1.15 (95% CI 0.93–1.43; P = .15) — not significantly different from placebo.¹
• In a pre-specified subgroup of 126 cats with evidence of chronic kidney disease, the relative risk of at least one adverse event was 1.09 (95% CI 0.78–1.52; P = .61) — again non-significant.¹
• Serum creatinine concentrations were marginally higher during robenacoxib administration (+4.36 μmol/L, 95% CI 0.21–8.50 μmol/L) without associated adverse clinical effects.¹
• Generalizability is limited: cats with severe or uncontrolled concomitant diseases were excluded, so the findings do not cover decompensated CKD or other severe comorbidities.
• 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.

Study design

King JN, Seewald W, Forster S, Friton G, Adrian DE, Lascelles BDX. (J Vet Intern Med 2021; PMID 34196973; JVIM 35[5]:2384–2394). Pooled analysis of 4 prospective, randomized, blinded clinical trials. Individual trial durations were 12 weeks (study 1), 4 weeks (study 2), and 6 weeks (studies 3 and 4). Cats received robenacoxib (target 1 mg/kg, range 1–2.4 mg/kg orally once daily) or matched placebo. Safety evaluation encompassed reported adverse events, hematology, serum biochemistry, and urinalysis.

Evidence summary

Overall adverse event profile

Robenacoxib was not associated with a statistically significant increase in adverse event risk over placebo in cats with chronic musculoskeletal disease treated for 4 to 12 weeks.¹ Numerically, 47.8% of robenacoxib-treated cats had at least one adverse event versus 41.0% of placebo-treated cats; the RR of 1.15 (95% CI 0.93–1.43) did not reach significance (P = .15).¹ The number of clinical signs per cat (range 0–9) also showed no significant between-group difference (P = .23).¹

Renal biomarker finding

Serum creatinine was statistically higher in the robenacoxib group compared with placebo (+4.36 μmol/L, 95% CI 0.21–8.50 μmol/L).¹ While this difference reached statistical significance, the absolute magnitude is small (approximately 0.05 mg/dL in conventional units), and no cats in the robenacoxib group experienced clinically detectable adverse renal effects attributable to this change.¹ This finding nonetheless supports the guideline recommendation for periodic creatinine monitoring during long-term robenacoxib use.

CKD subgroup: the critical question

The 126-cat CKD subgroup analysis is the most clinically significant component of this pooled dataset for practitioners managing cats with concurrent musculoskeletal disease and renal disease — a combination whose high co-prevalence (CKD found in 68.8% of cats recruited for DJD studies in one retrospective cohort) makes this safety question clinically urgent.² The relative risk of at least one adverse event in CKD cats receiving robenacoxib versus placebo was 1.09 (95% CI 0.78–1.52, P = .61).¹ This indicates no statistically significant increase in adverse event risk in cats with evidence of CKD receiving robenacoxib for 4–12 weeks. However, it is critical to note: these were cats without severe, uncontrolled concomitant diseases. Cats with IRIS Stage 3–4 CKD, uncontrolled hypertension, or active proteinuria were not represented, limiting the applicability of these reassuring findings to those subpopulations.

Clinical application

These data support the 2024 ISFM/AAFP consensus framework that robenacoxib can be used in cats with stable, early CKD with appropriate monitoring — and provide the specific risk quantification (RR ~1.09 in CKD) underpinning that guidance. Practical monitoring: baseline renal panel before initiation; re-check at 2–4 weeks, then every 3–6 months for stable patients; more frequent monitoring if CKD stage increases or clinical signs change.

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References

1. King JN, Seewald W, Forster S, Friton G, Adrian DE, Lascelles BDX. 2021. Clinical safety of robenacoxib in cats with chronic musculoskeletal disease. J Vet Intern Med 35(5):2384-2394. https://europepmc.org/articles/PMC8478032
2. Marino CL, Lascelles BD, Vaden SL, Gruen ME, Marks SL. 2014. Prevalence and classification of chronic kidney disease in cats randomly selected from four age groups and in cats recruited for degenerative joint disease studies. J Feline Med Surg 16(6):465-472. https://europepmc.org/articles/PMC4414065

Changelog

• 2026-06-23: First published.

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For licensed veterinary professionals. Evidence summary, not clinical advice. Voyage is decision support, not a substitute for clinical judgment — always confirm dosing and treatment with current formularies and your own clinical judgment.