Lokivetmab (Cytopoint) for Canine Atopic Dermatitis: IL-31 Targeting and Clinical Evidence

Bottom line.

• Lokivetmab (Cytopoint) is a caninized monoclonal antibody targeting interleukin-31, the primary pruritogenic cytokine in canine atopic dermatitis, providing targeted biological control of itch without systemic immunosuppression.^1
• Phase III randomized controlled trials demonstrated significant reductions in pruritus visual analogue scale scores versus placebo within 24-48 hours of subcutaneous injection, with effect duration typically 4-8 weeks.^2
• A 12-month prospective cohort study found 87% of dogs maintained pruritus scores below their Day 0 baseline throughout the study period, with 93% of owners reporting satisfaction.^3
• In dogs failing oclacitinib or lokivetmab monotherapy, combination therapy (COLT) produced a 61% reduction in pruritus scores in 61% of cases.^4
• Adverse event profile across trials is low; no clinically significant immunogenicity or injection-site reactions beyond mild transient events were identified in pivotal studies.^1,2

Drug facts

• Class: Caninized anti-IL-31 monoclonal antibody (IgG4-kappa isotype)
• Mechanism: Binds free canine interleukin-31 (IL-31), preventing binding to the IL-31RA/OSMR receptor complex on sensory neurons and keratinocytes; interrupts the itch-scratch cycle without broad immunosuppression
• Route/interval: Subcutaneous injection; US label recommends at least every 4-8 weeks as needed
• Indication: Control of pruritus associated with allergic dermatitis in dogs (FDA-approved NADA 141-514; EMA authorized as Cytopoint)
• Approval: FDA full approval; EMA authorized; available in most major markets
• Label contraindications: None listed; use caution in dogs with known hypersensitivity
• Label common AEs: Lethargy and gastrointestinal signs reported rarely in post-market data; injection site reactions uncommon

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What the evidence shows

Pivotal randomized controlled trials

Lokivetmab was evaluated in two companion pivotal blinded, randomized, placebo-controlled trials conducted by Michels et al. (2016), both published in Veterinary Dermatology. The first was a dose-determination trial (PMID 27647569) enrolling client-owned dogs with atopic dermatitis. Dogs were randomized to receive a single subcutaneous injection of lokivetmab at one of several doses or placebo, with pruritus assessed by owners and investigators. The study established dose-response relationships and identified the clinically effective dose range carried forward to label. The second trial (PMID 27647513) confirmed safety at the selected dose in a blinded, randomized, placebo-controlled design. Pruritus scores fell significantly in treated groups versus placebo, and no clinically significant adverse effects attributable to lokivetmab were identified. Both trials used the pruritus Visual Analog Scale (pVAS) as the primary instrument, with CADESI (Canine Atopic Dermatitis Extent and Severity Index) as a secondary skin lesion measure.

Comparison with ciclosporin

Moyaert et al. (2017; PMID 28906040) conducted a blinded, randomized clinical trial comparing lokivetmab directly to ciclosporin in client-owned dogs with atopic dermatitis. The study found lokivetmab non-inferior to ciclosporin on pruritus outcomes at 16 weeks, with a faster onset of effect at Day 14. Gastrointestinal adverse events were more frequent in the ciclosporin arm. This trial was important in establishing lokivetmab as a practical alternative to systemic calcineurin inhibitors for ongoing management.

Real-world effectiveness: multinational field study

Van Brussel, Moyaert et al. (2021; PMID 34180084) reported a masked, randomised clinical trial in client-owned dogs with allergic dermatitis, evaluating lokivetmab against saline control in a field setting. Dogs were randomized to receive lokivetmab or saline, with PVAS and CADESI-4 measured at Day 14 and 28. The lokivetmab group showed statistically significant and clinically meaningful reductions in both pruritus and skin lesion scores at both time points. The study confirmed efficacy in a diverse clinical population across multiple European practices.

Long-term 12-month cohort

Gober et al. (2025; PMID 40133889), in a BMC Veterinary Research cohort study, followed 75 dogs receiving lokivetmab at US label dosing over 12 months, with evaluations at Day 180 and Day 365:

• 87% (64/75) maintained PVAS below their Day 0 baseline
• 88% (65/75) achieved a mean biweekly PVAS below 36 mm (threshold for adequate control)
• 31% (23/75) maintained PVAS below 36 for the entire study
• 11% (8/75) maintained PVAS below 20 (considered normal itch level) throughout
• 93% of owners expressed satisfaction; 80% reported being able to reduce concurrent medications

The study was sponsored by Zoetis; the cohort design under label dosing provides clinically relevant durability data not available from short-term pivotal trials.

Combination with oclacitinib after monotherapy failure

Bachtel and Snidow (2026; PMID 41189387) conducted a retrospective study at a specialty referral center evaluating 44 dogs that had failed both oclacitinib and lokivetmab as separate monotherapies, who were then transitioned to combination oclacitinib-lokivetmab therapy (COLT):

• 61.4% (27/44) achieved treatment success (at least 2 cm pVAS reduction plus clinician/owner consensus)
• In responders, mean pVAS fell from 6.87 to 2.67 out of 10 (61.1% decrease; p less than 0.0001)
• No adverse effects were observed in the COLT group

These findings suggest mechanistic complementarity between JAK1 inhibition (oclacitinib) and upstream IL-31 neutralization (lokivetmab). The retrospective single-center design limits generalizability.

How this fits clinical practice

IL-31 targeting with lokivetmab occupies a distinct mechanistic position from JAK inhibitors like oclacitinib. Clinicians working with cases where oclacitinib does not achieve adequate pruritus control, or where owner preference favors a monthly-to-bimonthly injectable rather than daily oral therapy, frequently consider lokivetmab.

The onset profile - typically within 24-48 hours in trial data - is useful for acute flare management pending longer-term workup. The absence of a required pre-treatment laboratory profile differentiates it from ciclosporin.

For patients failing monotherapy, the COLT evidence base is supported by a structured retrospective study. Clinicians considering COLT should document failure of each agent independently before combination use. Dosing and re-injection intervals should follow current label guidance and be individualized based on owner-reported pruritus. Voyage Clinical Desk can assist with weight-specific calculations and monitoring checklists.

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References

1. Michels GM, Ramsey DS, Walsh KF, et al. A blinded, randomized, placebo-controlled, dose determination trial of lokivetmab (ZTS-00103289), a caninized, anti-canine IL-31 monoclonal antibody in client owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):478-e129. https://pubmed.ncbi.nlm.nih.gov/27647569/
2. Michels GM, Walsh KF, Kryda KA, et al. A blinded, randomized, placebo-controlled trial of the safety of lokivetmab (ZTS-00103289), a caninized anti-canine IL-31 monoclonal antibody in client-owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):505-e136. https://pubmed.ncbi.nlm.nih.gov/27647513/
3. Gober M, Amodie D, Mellencamp M, Hillier A. Long term use of lokivetmab (Cytopoint) in atopic dogs. BMC Vet Res. 2025;21(1):203. https://pubmed.ncbi.nlm.nih.gov/40133889/
4. Bachtel JC, Snidow M. Efficacy of Combination Oclacitinib and Lokivetmab Therapies After Monotherapeutic Failure in 44 Dogs: A Retrospective Study. Vet Dermatol. 2026;37(2):287-292. https://pubmed.ncbi.nlm.nih.gov/41189387/
5. Van Brussel L, Moyaert H, Escalada M, et al. A masked, randomised clinical trial evaluating the efficacy and safety of lokivetmab compared to saline control in client-owned dogs with allergic dermatitis. Vet Dermatol. 2021;32(5):477-e131. https://pubmed.ncbi.nlm.nih.gov/34180084/
6. Moyaert H, Van Brussel L, Borowski S, et al. A blinded, randomized clinical trial evaluating the efficacy and safety of lokivetmab compared to ciclosporin in client-owned dogs with atopic dermatitis. Vet Dermatol. 2017;28(6):593-e145. https://pubmed.ncbi.nlm.nih.gov/28906040/

Changelog

• 2026-06-09: First published.

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