Canine Atopic Dermatitis: Apoquel, Cytopoint, and Treatment Options

Both oclacitinib (Apoquel) and lokivetmab (Cytopoint) are rapidly acting, evidence-based systemic options for the symptomatic control of canine atopic dermatitis (AD), and they occupy the same fast-relief rung of the AD treatment ladder. Oclacitinib, an oral selective Janus kinase 1 (JAK1) inhibitor, produced an onset of efficacy within 24 hours in its pivotal blinded trial. Lokivetmab, an injectable caninized monoclonal antibody against canine IL-31, separated from placebo on owner-assessed pruritus from day 1 through day 49 at the 2 mg/kg dose, and at 0.5 and 2.0 mg/kg reduced pruritus for at least 1 month. No blinded head-to-head trial in client-owned dogs has been published; the only direct comparison is a 19-dog research-colony study in which both drugs were clinically active, and a 2022 knowledge summary judged the comparative evidence insufficient to call either drug superior.

Mechanisms and onset of action

Oclacitinib (Apoquel) is an oral selective Janus kinase 1 inhibitor that, per the pivotal trial background, inhibits the function of a variety of pro-inflammatory, pro-allergic and pruritogenic cytokines dependent on Janus kinase enzyme activity. In a randomized, double-blinded, placebo-controlled trial, 436 client-owned dogs with moderate-to-severe owner-assessed pruritus and a presumptive diagnosis of allergic dermatitis received oclacitinib 0.4–0.6 mg/kg orally twice daily or excipient-matched placebo: oclacitinib produced a rapid onset of efficacy within 24 hours, mean owner Pruritus VAS scores fell from 7.58 to 2.59 cm, scores were significantly better than placebo on each assessment day (P < 0.0001), and day 7 veterinarian Dermatitis VAS scores were also significantly better than placebo (P < 0.0001). Diarrhoea and vomiting were reported with similar frequency in both groups. In the 299-dog atopic dermatitis trial, the regimen was 0.4–0.6 mg/kg orally twice daily for 14 days, then once daily.

Lokivetmab (Cytopoint) is a caninized anti-canine IL-31 monoclonal antibody given by subcutaneous injection. Per the Zoetis package insert, IL-31 has been shown to induce pruritus in dogs in laboratory studies. In the dose-determination trial of 211 client-owned dogs with chronic AD enrolled at 15 referral clinics, a single 2 mg/kg dose produced a greater percentage reduction from baseline than placebo in owner-assessed pruritus on days 1–49 and in clinician-assessed CADESI-03 scores on days 7–56 (P < 0.05); lower doses separated later and for shorter durations (owner-assessed pruritus: 0.5 mg/kg days 2–35, 0.125 mg/kg days 7–21). Lokivetmab at 0.5 and 2.0 mg/kg reduced pruritus versus placebo for at least 1 month, with the level and duration of response increasing with dose. The labeled dosing, per the same insert, is a minimum of 0.9 mg/lb (2 mg/kg) subcutaneously, with repeat administration every 4–8 weeks as needed in individual patients; Cytopoint is supplied in 1-mL vials in four concentrations (10, 20, 30 and 40 mg).

Pivotal efficacy trials

Oclacitinib

In the blinded, randomized, placebo-controlled trial of 299 client-owned dogs with chronic AD enrolled at 18 specialty clinics (oclacitinib 0.4–0.6 mg/kg twice daily for 14 days, then once daily for up to 112 days, versus excipient-matched placebo), owner-assessed pruritus fell 29.5, 42.3, 61.5, 66.7 and 47.4% from baseline on days 1, 2, 7, 14 and 28, versus 6.5, 9.1, 6.5, 3.9 and 10.4% with placebo; differences were significant at all time points assessed (P < 0.0001). Dermatologists recorded a 48.4% reduction in CADESI-02 scores on days 14 and 28 with oclacitinib, versus a 1.7% reduction and a 3.6% increase with placebo. After day 28, more than 86% of placebo-treated dogs had moved to an open-label study, so later between-group comparisons were biased.

Lokivetmab

In the blinded, randomized, placebo-controlled dose-determination trial of 211 client-owned dogs with chronic AD, dogs received a single subcutaneous dose of lokivetmab 0.125, 0.5 or 2.0 mg/kg or placebo. At 2.0 mg/kg, lokivetmab produced a greater reduction from baseline than placebo in owner-assessed pruritus on days 1–49 and in CADESI-03 scores on days 7–56 (P < 0.05); lower doses separated later and for shorter durations (owner-assessed pruritus: 0.5 mg/kg days 2–35 and 0.125 mg/kg days 7–21; CADESI-03: day 14 for both lower doses). Safety was assessed in a separate randomized, double-blind, placebo-controlled trial of 245 client-owned dogs with chronic AD, randomized 2:1 to lokivetmab (1.0–3.3 mg/kg subcutaneously on days 0 and 28) or placebo: there were no immediate hypersensitivity reactions; discomfort at administration occurred in 5.1% of dogs at similar frequency and severity in both groups; pruritus was reported as an adverse event less frequently with lokivetmab (4.9% versus 19.3%); there were no clinically important between-group differences in clinical pathology; treatment-induced immunogenicity occurred in 2.5% of lokivetmab-treated dogs; and a wide variety of concomitant medications was used with no clinically apparent adverse interactions. The authors concluded that two monthly doses of lokivetmab were safe over a 42-day period.

Head-to-head evidence

No blinded, randomized head-to-head comparison of oclacitinib and lokivetmab in client-owned dogs has been published. The only direct comparison is a blinded, randomized, controlled study of 19 atopic beagle dogs in a research colony, challenged with allergen twice weekly and randomized to oclacitinib, ciclosporin, lokivetmab, prednisone, or no treatment for four weeks. In the first two weeks, CADESI scores were significantly lower than controls for prednisone (P = 0.019) and oclacitinib (P = 0.015), while lokivetmab prevented flares; due to variability, no significant differences in pruritus were observed among groups. Transepidermal water loss increased over time in controls and the ciclosporin group but not in the oclacitinib and lokivetmab groups, and area-under-the-curve hydration was higher for lokivetmab (P = 0.014) and oclacitinib (P = 0.04) than controls; CADESI-03 correlated with both transepidermal water loss (P = 0.0043) and pruritus (P = 0.0283). The authors concluded that lokivetmab prevented flares when given before challenge, and that oclacitinib and lokivetmab have some positive effects on skin barrier parameters.

A 2022 Veterinary Evidence knowledge summary that critically appraised the comparative literature rated the strength of evidence weak: the one randomized controlled trial found both drugs similar in reducing CADESI-03, and a before-and-after study noted that dogs’ response to oclacitinib can be used to predict response to lokivetmab. The summary concluded there is insufficient quality of evidence to determine whether lokivetmab is more effective than oclacitinib, and that further comparative study is required.

The rest of the ladder

Against ciclosporin, oclacitinib had a faster onset of action and fewer gastrointestinal adverse effects in a blinded, randomized trial of 226 client-owned dogs with AD (with a noninferiority test at day 28; oclacitinib 0.4–0.6 mg/kg twice daily for 14 days then once daily, versus ciclosporin 3.2–6.6 mg/kg once daily, for 12 weeks). Owner-assessed pruritus reductions ranged from 25.6% on day 1 to 61.0% on day 84 with oclacitinib, versus 6.5% to 61.5% with ciclosporin, with differences significant at all time points up to day 28; by day 56 the two drugs showed similar decreases in pruritus. The day-14 CADESI-02 reduction was significantly greater with oclacitinib (58.7% versus 43.0%), and three times as many adverse events attributed to gastrointestinal signs were reported in the ciclosporin group.

After monotherapy failure, a 2026 retrospective study reported 44 client-owned dogs with allergic dermatitis that did not respond to both oclacitinib and lokivetmab as monotherapies; treated with the combination, 27 of 44 (61.4%) responded adequately (≥ 2 cm reduction in pruritus VAS from baseline plus client/clinician consensus), responders’ mean pruritus VAS fell from 6.87 to 2.67 of 10 (61.1% decrease; p < 0.0001), and no adverse effects were noted.

Clinical context and limitations

Both pivotal programs were placebo-controlled; neither drug has been compared head-to-head with the other in a blinded trial of client-owned dogs, so claims of relative superiority are not supported by the current literature. Cross-trial comparisons are confounded by differing outcome instruments (owner-assessed pruritus VAS; CADESI-02 in the oclacitinib trials versus CADESI-03 in the lokivetmab dose trial) and differing populations (presumptive allergic dermatitis versus chronic AD; specialty and referral clinic recruitment). Randomized controlled data extend to 112 days for oclacitinib (with the placebo-group open-label crossover after day 28 biasing later between-group comparisons) and to 56 days for lokivetmab (dose determination), with safety evaluated over 42 days. The only direct comparison used 19 research-colony beagles under twice-weekly allergen challenge, a flare-prevention model rather than natural client-owned AD, and it did not separate the drugs on pruritus. The combination-therapy evidence is retrospective, from 44 dogs, and not a randomized comparison.

Ask Vetinuity

For follow-up questions about the dosing regimens, the comparative evidence, or the rest of the treatment ladder, ask the Vetinuity clinical assistant.