A double‐blinded, randomized, methylprednisolone‐controlled study on the efficacy of oclacitinib in the management of pruritus in cats with nonflea nonfood‐induced hypersensitivity dermatitis

Open trial of recombinant Der f 2 pullulan-conjugated immunotherapy in cats

BACKGROUND

Allermmune HDM (Zenoaq) is a recombinant Dermatophagoides farinae 2 (Der f 2) pullulan-based immunotherapy vaccine whose efficacy on house dust mite allergic dogs has been demonstrated. There is no published information on its use in cats.

OBJECTIVES

The objective of the study was to evaluate the safety and short-term effects of Allermmune HDM in Dermatophagoides farinae (Df)-sensitised cats.

MATERIALS AND METHODS

Eleven cats diagnosed with atopic skin syndrome received Allermmune weekly for six weeks then monthly for three months (total duration 18 weeks). On Weeks 0, 6 and 18 clinical lesions were assessed by the Feline Dermatitis Extent and Severity Index (FEDESI); owners assessed pruritus with a 10-cm Visual Analog Scale (pVAS). Concurrent medication use was recorded. The allergen-specific immunoglobulin (Ig)E were measured before study inclusion with a commercial serological assay.

RESULTS

There were no evident adverse effects. FEDESI and pVAS improved significantly after six weeks (p = 0.001 and p = 0.01, respectively). The pretreatment Df-specific IgE levels were significantly higher in the cats with improved clinical scores than in the cats with no clinical score change (p = 0.009).

CONCLUSIONS AND CLINICAL RELEVANCE

Allermmune HDM may be safe in cats and has the potential to alleviate signs of atopic skin syndrome. Allergen-specific IgE levels may represent an efficacy marker. Controlled studies of longer duration and larger sample size are worth pursuing.

Development and validation of an owner-assessed Visual Analog Scale for feline pruritus severity scoring (VAScat)

BACKGROUND

Assessment of the severity of pruritus is difficult in cats, because they manifest discomfort by increased licking, increased scratching or both.

HYPOTHESIS/OBJECTIVES

Our objective was to develop and validate a feline-specific pruritus scale (VAScat).

METHODS

The scale was designed as a double Visual Analog Scale (VAS), one VAS for licking and one for scratching, with severity and behavioural descriptors. The highest score (VAS-max) on either VAS was taken as the pruritus score for each cat. Owners of 153 cats with skin diseases and of 108 healthy cats scored their pet's pruritus using the VAScat. Ninety-six of 153 cats with skin diseases also were re-evaluated after four to eight weeks of treatment.

RESULTS

Pearson's correlation value between VAS-licking and VAS-scratching scores was r = 0.26 (p < 0.01), and Cronbach's alpha was 0.41. Both indexes indicated that the two scales measure different manifestations of pruritus and supported the use of a dual assessing system. Comparison with a numerical pruritus severity scale (0, absent; 1, mild; 2, moderate; 3, severe) suggested that VAS-licking and VAS-scratching scales taken alone are unsuitable for measuring absent to mild pruritus (grades 0-1), while VAS-max is (p = 0.001). VAS-licking, VAS-scratching and VAS-max all were suitable to assess higher levels of pruritus (grades 2-3, p < 0.01). The VAScat was able to measure pruritus improvement following therapy, as post-treatment scores were significantly decreased compared to pre-treatment ones (p < 0.0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

The VAScat proved to be a useful tool to assess pruritus in cats and for monitoring the response to treatment for pruritus.

Fatal disseminated toxoplasmosis in a feline immunodeficiency virus‐positive cat receiving oclacitinib for feline atopic skin syndrome

Toxoplasma gondii is a ubiquitous protozoan, for which felids are the definitive host. Immunocompromised individuals are susceptible to recrudescent toxoplasmosis. This case describes a 6‐year‐old, feline immunodeficiency virus‐positive domestic short hair cat with feline atopic skin syndrome that developed fatal toxoplasmosis after treatment with oclacitinib for five months.

Cytokine expression in feline allergic dermatitis and feline asthma

BACKGROUND

The pathogenesis of feline allergic dermatitis (FAD) is unclear, with several differences from allergic dermatitis in dogs and humans.

HYPOTHESIS/OBJECTIVES

To survey cytokine expression levels in healthy cats and cats affected with allergic dermatitis or asthma.

ANIMALS

Formalin-fixed, paraffin-embedded skin biopsies from 22 cats with allergic dermatitis and 21 cats without allergic dermatitis were used for cutaneous assays. Serum was obtained from 17 healthy cats, 18 cats with allergic dermatitis, and 18 cats with a presumptive diagnosis of asthma.

METHODS AND MATERIALS

Cutaneous mRNA expression was evaluated with quantitative PCR [interleukin (IL)-31 and IL-31 Receptor A] and RNA in situ hybridisation (ISH) [IL-5, IL-31, IL-31RA, IL-33 and Oncostatin M receptor (OSMR)-β]. IL-31 protein concentrations were evaluated in serum with an enzyme-linked immunosorbent assay. Serum levels of 19 additional cytokines were evaluated using a Luminex panel.

RESULTS

IL-31, IL-31RA, IL-5 and IL-33 mRNA expression were either expressed in low quantities or undetectable in most samples. By contrast, OSMR-β expression was significantly higher in the skin of allergic versus healthy cats (P < 0.0001). Although serum IL-31 was detected in a larger number of cats with allergic dermatitis than healthy cats, and concentrations appeared to be higher in cats with allergies, this difference was not statistically significant. Cats affected by asthma also exhibited insignificantly higher concentrations of IL-31 in the serum.

CONCLUSIONS AND CLINICAL RELEVANCE

Our results suggest that feline allergic diseases may exhibit different pathomechanisms from allergic diseases affecting other species. These findings are useful in guiding further therapeutic development toward targets that may have a role in the pathogenesis of feline allergic skin disease.

Atopic Dermatitis in Domestic Animals: What Our Current Understanding Is and How This Applies to Clinical Practice

Atopic dermatitis is a clinical syndrome that affects both people and animals. Dogs closely mimic the complexity of the human skin disease, and much progress has been made in recent years in terms of our understanding of the role of skin impairment and the identification of new treatments. Cats and horses also develop atopic syndromes which include both cutaneous and respiratory signs, yet studies in these species are lagging. It is now recognized that atopic dermatitis is not a single disease but a multifaceted clinical syndrome with different pathways in various subgroups of patients. Appreciating this complexity is clinically relevant as we develop more targeted treatments which may work well in some patients but not in others. Different phenotypes of atopic dermatitis have been described in dogs, and it is possible that phenotypes related to breed and age may exist in other animals similar to how they are described in people. The awareness of different mechanisms of disease leads to the desire to correlate different phenotypes with specific biomarkers and responses to treatment. In this review, the current understanding and updated information on atopic syndrome in animals are described, highlighting opportunities for further studies in the future.

Treatment of the feline atopic syndrome - a systematic review

BACKGROUND

Feline allergic skin disease and asthma occur regularly in small animal practice.

OBJECTIVES

To provide evidence-based recommendations for small animal practitioners on the treatment of feline atopic syndrome (FAS).

METHODS AND MATERIALS

The authors reviewed the literature available before February 2020, prepared a detailed evidence-based literature review and made recommendations based on the evaluated evidence.

RESULTS

Sixty-six papers and abstracts were identified describing treatment interventions for FAS and evaluated to establish treatment recommendations. For many treatment options, the papers were retrospective, open studies or case reports.

CONCLUSION AND CLINICAL RELEVANCE

In this review, there was good evidence for the efficacy of systemic glucocorticoids and ciclosporin, and limited evidence for the efficacy of topical glucocorticoids, oclacitinib and allergen-specific immunotherapy in feline atopic skin syndrome. Evidence pointed to low-to-moderate efficacy for antihistamines, fatty acids and palmitoyl ethanolamide. In feline asthma, there was good evidence for the efficacy of oral and inhaled glucocorticoids, and limited evidence of moderate efficacy for allergen-specific immunotherapy. Evidence supported low-to-moderate efficacy of mesenchymal stem cells, inhaled lidocaine and oclacitinib as treatments for feline asthma. For almost all therapeutic options (with the exception of glucocorticoids and ciclosporin), more randomised controlled trials are needed.

Successful Treatment of a Multi-Drug-Resistant Severely Pruritic Hypersensitivity Dermatitis in a Cat

A 3-year-old neutered female domestic shorthair cat was presented with a severely pruritic dermatitis. After exclusion of flea allergy dermatitis, ectoparasite infestation, retroviral infection, neoplasia, and cutaneous adverse food reaction, a diagnosis of nonflea, nonfood hypersensitivity dermatitis (NFNFHD) was made. The resolution of complicating bacterial infection and yeast overgrowth did not improve the animal's condition. Numerous antipruritic treatment modalities used during the investigation proved unsuccessful, including anti-inflammatory and immunosuppressive prednisolone doses, oclacitinib, antihistamines, ciclosporin A, and supplementation with essential fatty acids. Allergen-specific serology test results were negative. Treatment with oral dexamethasone allowed a complete resolution of clinical signs. The cat has been successfully maintained in remission for over 12 months. To the author's knowledge, this is the first case report of a cat with multi-drug-resistant NFNFHD treated successfully with dexamethasone.

A blinded, randomized, placebo-controlled trial of the safety of oclacitinib in cats

Background

Oclacitinib is a Janus kinase (JAK) 1 enzyme inhibitor and blocks JAK1-dependent cytokines and is used to control pruritus. Studies available in cats are very limited and as there is a potential role for oclacitinib in the control of pruritus in this specie, the aim of this study was to evaluate the safety and clinical effects of oral oclacitinib maleate in healthy cats.

Results

Thirty mixed-breed cats weighing from 2.1 to 5.3 kg each were randomly allocated to three treatment groups of 10 animals each. Cats in two groups received oclacitinib at 1 mg/kg or 2 mg/kg q 12 h orally for 28 days. Cats in the third group were given placebo tablets (cornstarch) q 12 h orally for 28 days. Oclacitinib maleate was well tolerated during the study and few adverse events were observed in treated cats. Clinical signs of toxicity were not observed in any animals treated at 1 mg/kg. Gastrointestinal clinical signs observed in the 2 mg/kg group included vomiting in two of the 10 cats and soft stools in two cats. One cat treated with placebo also exhibited soft stools. No significant differences were observed between the groups for hematologic analyses performed during the study. There was a slight increase in neutrophils and monocytes and a decrease in eosinophil mean counts in treated cats. Mean renal and liver enzymes remained normal throughout the entire study. A small, but significant increase in fructosamine levels was observed for both treated groups compared with placebo; however, values remained within the normal reference range. There were no significant difference between treated groups and the placebo group for urine specific gravity, pH, or urine protein to creatinine ratio mean values.

Conclusions

Oclacitinib maleate was well tolerated by cats at 1 mg/kg and 2 mg/kg and appeared to be safe for this species when administered orally twice daily for 28 days. More studies would be needed to demonstrate if oclacitinib maleate may be a suitable alternative to treat pruritic cats.