VetMedOsteoarthritis pain in cats: does short-course robenacoxib improve activity and pain measures? — POSSIBLE (the treatment made no difference to mean total activity)
In cats with osteoarthritis, does short-course robenacoxib vs placebo improve activity and pain measures?
Shelf #743 · gate-verified and displayed under the developer's blinded-trial rule
POSSIBLE (the treatment made no difference to mean total activity): One randomised, blinded pilot trial (Adrian 2021, 109 cats with degenerative joint disease-associated pain, two consecutive 3-week treatment periods) found owner-assessed disability significantly decreased on robenacoxib (p = 0.01; 49% reduction in disability; effect size ~0.3), with improved temperament (p = 0.0039) and happiness (p = 0.021) and more treatment successes at 6 weeks (p = 0.018; NNT 3.8); but the objective actimetry headline was null — mean total activity was 5.7% higher on robenacoxib than placebo, p = 0.24 (the treatment made no difference to mean total activity) — with only a responder analysis at the 80th percentile of activity favouring robenacoxib (p = 0.046 at 3 weeks, p = 0.026 at 6 weeks). Safety over short courses is comparatively well documented: a randomised blinded placebo-controlled trial of 194 cats (King 2016, 1.0-2.4 mg/kg daily for 28 days) found no differences in adverse events or laboratory variables, and a pooled analysis of 4 randomised blinded trials in 449 cats (King 2021, 4-12 weeks) found at least one adverse event in 47.8% on robenacoxib vs 41.0% on placebo (relative risk 1.15, 95% confidence interval 0.93-1.43). Design class (a): randomisation and blinding are both established by carded records — Adrian 2021 is titled 'a randomized and blinded pilot clinical trial' and King 2016 is a 'randomized, blinded, placebo-controlled clinical trial'. The honest limits: the efficacy evidence is a single pilot trial designed to identify endpoints for confirmatory studies, its objective activity measure was null on the mean, the owner-score effect size is small (~0.3), and the programme is the manufacturer's. Drafted Nov 10, 2026 (VetMed build, topic #743); all figures from abstracts fetched and verified at drafting.
Adrian 2021: robenacoxib reduced owner-assessed disability (p = 0.01; 49% reduction; effect size ~0.3) and produced more successes at 6 weeks (NNT 3.8), but mean total activity did not differ from placebo (p = 0.24)
Parallel-group randomized, blinded pilot clinical trial (record's own title wording: 'a randomized and blinded pilot clinical trial'; publication type: Randomized Controlled Trial, Veterinary)
Who: Cats: 109 otherwise healthy cats with degenerative joint disease-associated pain, in a parallel-group, randomized, blinded clinical trial. Cats received placebo or robenacoxib for two consecutive 3-week periods (treatment sequences placebo-placebo, robenacoxib-robenacoxib and robenacoxib-placebo); actimetry and owner-assessment data were collected (this record's abstract does not state the robenacoxib dose).
Result: Activity data showed high within-cat and between-cat variability, and 82.4% of values were zero. Compared with placebo, mean total activity was higher (5.7%) in robenacoxib-treated cats (p = 0.24) — not significant. For the 80th percentile of activity, more robenacoxib-treated cats had a >10% increase in activity after 3 weeks (p = 0.046) and 6 weeks (p = 0.026). Robenacoxib significantly decreased owner-assessed disability (p = 0.01; 49% reduction in disability; effect size ~0.3) and improved temperament (p = 0.0039) and happiness (p = 0.021) after 6 weeks. More robenacoxib-treated cats were successes at 6 weeks (p = 0.018; NNT 3.8). Adverse effect frequencies were similar across groups.
Watch out: A pilot trial whose stated main objective was to evaluate outcome measures for confirmatory studies — not a confirmatory efficacy trial. The objective activity endpoint is null on its mean and positive only in a responder cut at the 80th percentile; the owner-score benefits carry a small effect size (~0.3) and are vulnerable to caregiver placebo effects, which is why the stamp is POSSIBLE and the null is scoped to mean total activity. Several authors are from the robenacoxib developer's programme (the companion safety cards are the same programme).
Adrian D, King JN, Parrish RS, King SB, Budsberg SC, Gruen ME, Lascelles BDX. Robenacoxib shows efficacy for the treatment of chronic degenerative joint disease-associated pain in cats: a randomized and blinded pilot clinical trial. Sci Rep. 2021;11(1):7721. PMID: 33833276. Registry ID: none in the record. MeSH: Animals · Cat Diseases/drug therapy* · Cats · Diphenylamine/analogs & derivatives*, therapeutic use · Female · Joint Diseases/complications, veterinary* · Male · Osteoarthritis/complications, veterinary* · Pain/complications, veterinary* · Pain Management/veterinary* · Phenylacetates/therapeutic use* · Pilot Projects · Placebos
King 2016: robenacoxib 1.0-2.4 mg/kg daily for 28 days in 194 cats with osteoarthritis (including 40 with concurrent chronic kidney disease) showed no differences from placebo in adverse events, body weight or laboratory variables
Randomized, blinded, placebo-controlled clinical trial — safety primary (record's own title wording; publication type: Randomized Controlled Trial)
Who: Cats: 194 cats with osteoarthritis randomly allocated to robenacoxib at 1.0-2.4 mg/kg (n = 95) or placebo (n = 99) tablets orally every 24 hours for 28 days; safety was assessed in 193 cats, including a subgroup of 40 with concurrent chronic kidney disease (serum creatinine ⩾1.6 mg/dl and urine specific gravity <1.030).
Result: In all 193 cats and in the subgroup of 40 animals with concurrent chronic kidney disease, there were no differences between groups in frequencies of reported adverse events, body weight change or results of serum or urine chemistry or haematology variables. The record concludes robenacoxib was well tolerated when administered daily for 1 month in cats with osteoarthritis, including cats with evidence of concurrent chronic kidney disease, with no clinical indication of damage to the gastrointestinal tract, kidney or liver.
Watch out: A safety trial: it reports no efficacy (activity or pain) outcomes, so it cannot support the benefit claim — it is carded as the short-course tolerability record for the doses the efficacy pilot used. Twenty-eight days in trial-selected cats does not establish safety of longer or repeated courses, or in cats with more advanced kidney disease than the subgroup studied.
King JN, King S, Budsberg SC, Lascelles BD, Bienhoff SE, Roycroft LM, Roberts ES. Clinical safety of robenacoxib in feline osteoarthritis: results of a randomized, blinded, placebo-controlled clinical trial. J Feline Med Surg. 2016;18(8):632-42. PMID: 26058587. Registry ID: none in the record. MeSH: Animals · Anti-Inflammatory Agents, Non-Steroidal/adverse effects*, therapeutic use · Cat Diseases/drug therapy* · Cats · Diphenylamine/adverse effects, analogs & derivatives*, therapeutic use · Osteoarthritis/drug therapy, veterinary* · Phenylacetates/adverse effects*, therapeutic use
King 2021 (pooled, 449 cats): at least one adverse event in 47.8% on robenacoxib vs 41.0% on placebo over 4-12 weeks (relative risk 1.15, 95% CI 0.93-1.43); serum creatinine slightly higher on robenacoxib (+4.36 µmol/L, 95% CI 0.21-8.50) with no related clinical effects
Pooled analysis of 4 prospective randomized blinded clinical trials (record's own wording; safety outcomes)
Who: Cats: 449 client-owned cats with chronic musculoskeletal disease, pooled from 4 prospective randomized blinded clinical trials of robenacoxib (n = 222) vs placebo (n = 227), administered orally once daily for 4 to 12 weeks; a subgroup of 126 cats had evidence of chronic kidney disease.
Result: The number of cats with at least 1 adverse event was not significantly different (P = .15) with robenacoxib (n = 106, 47.8%) compared with placebo (n = 93, 41.0%); the relative risk of at least 1 adverse event (incidence robenacoxib/placebo) was 1.15 (95% confidence interval 0.93-1.43). There was no significant difference between groups in the number of clinical signs (range 0-9) per cat (P = .23). Serum creatinine concentrations were higher during robenacoxib administration than placebo (+4.36 µmol/L, 95% confidence interval 0.21-8.50), but no related adverse clinical effects were detected. In the 126-cat chronic kidney disease subgroup, the relative risk of at least 1 adverse event was 1.09 (95% confidence interval 0.78-1.52, P = .61).
Watch out: Pooled safety analysis from the manufacturer's programme, not an efficacy record. The record itself limits generalisability: cases with severe and uncontrolled concomitant diseases were not included. The creatinine difference is a laboratory signal without detected clinical effects in these trials — neither proof of renal harm nor proof of renal safety beyond 12 weeks.
King JN, Seewald W, Forster S, Friton G, Adrian DE, Lascelles BDX. Clinical safety of robenacoxib in cats with chronic musculoskeletal disease. J Vet Intern Med. 2021;35(5):2384-2394. PMID: 34196973. Registry ID: none in the record. MeSH: Animals · Anti-Inflammatory Agents, Non-Steroidal/adverse effects · Cat Diseases*/drug therapy · Cats · Diphenylamine/adverse effects, analogs & derivatives · Musculoskeletal Diseases*/drug therapy, veterinary · Phenylacetates · Prospective Studies
Synthesis: short-course robenacoxib improves owner-assessed pain and disability scores in cats with joint pain, with no demonstrated increase in mean activity — POSSIBLE
Synthesis
Who: Synthesis of the cards above: Adrian 2021 (randomized blinded pilot, 109 cats with degenerative joint disease-associated pain, two 3-week periods), King 2016 (randomized blinded placebo-controlled safety trial, 194 cats with osteoarthritis, 28 days) and King 2021 (pooled safety analysis of 4 randomized blinded trials, 449 cats with chronic musculoskeletal disease, 4-12 weeks).
Result: (1) Owner-side outcomes favour robenacoxib: disability down (p = 0.01, 49% reduction, effect size ~0.3), temperament and happiness improved, more successes at 6 weeks (NNT 3.8). (2) The objective activity mean does not move: +5.7% vs placebo, p = 0.24; only the 80th-percentile responder analysis is positive. (3) Short-course tolerability is the best-documented part: no adverse-event or laboratory separation from placebo at 28 days (King 2016) and a non-significant relative risk of 1.15 for any adverse event across 4-12 weeks in 449 cats (King 2021), with absolute rates 47.8% vs 41.0%. One pilot efficacy trial with a null objective headline supports POSSIBLE, not higher.
Watch out: This shelf is about short courses (3-6 weeks of treatment in the efficacy pilot; up to 12 weeks in the pooled safety data) in cats with degenerative joint disease / osteoarthritis pain. It does not address indefinite daily use, and it is a different drug home from Shelf #196 (long-term low-dose meloxicam in older cats) and a different species and drug from Shelf #182 (bedinvetmab vs meloxicam in dogs) — no record from those shelves is re-carded here, and results are not transported between them.
Synthesis of Adrian D et al. PMID: 33833276; King JN et al. PMID: 26058587; King JN et al. PMID: 34196973. Registry IDs as on the individual cards.
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