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Efficacy of a Bruton's Tyrosine Kinase Inhibitor (PRN‐473) in the treatment of canine pemphigus foliaceus
Author(s) -
Goodale Elizabeth C.,
Varjonen Katarina E.,
Outerbridge Catherine A.,
Bizikova Petra,
Borjesson Dori,
Murrell Dedee F.,
Bisconte Angelina,
Francesco Michelle,
Hill Ronald J.,
Masjedizadeh Mohammad,
Nunn Philip,
Gourlay Steven G.,
White Stephen D.
Publication year - 2020
Publication title -
veterinary dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.744
H-Index - 60
eISSN - 1365-3164
pISSN - 0959-4493
DOI - 10.1111/vde.12841
Subject(s) - pemphigus foliaceus , medicine , dermatology , immunology , antibody , autoantibody
Background Bruton's tyrosine kinase (BTK) is important in B‐cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is the most common canine autoimmune skin disease. Objectives To determine the safety and efficacy of a BTKi in cPF treatment. Animals Nine privately owned dogs. Methods and materials Nine dogs diagnosed with PF were administered BTKi PRN473. Initial dosages were ≈15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for a maximum of 20 weeks, attempting decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels, urinalyses and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Anti‐desmocollin‐1 (DSC‐1) and desmoglein‐1 (DSG‐1) immunoglobulin G (IgG) titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells. Results All nine dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. At the end of the study, four responses were considered “good”, two “fair”, two “poor” and one dog withdrawn due to recurrence of a previously excised mast cell tumour. Four dogs continued to improve by Week 4; three sustained near complete remission by study's end. The anti‐DSC‐1 IgG titre decreased in three dogs, increased in two, was undetected in three and was not performed in the withdrawn dog. No dogs had detectable IgG to DSG1. Possible adverse effects occurred in three dogs. Conclusions and clinical importance Bruton's tyrosine kinase inhibitor monotherapy may have beneficial effects in some cases of cPF.