Efficacy and Safety of Allogeneic Mesenchymal Stromal Cells Versus Lokivetmab in Mild‐To‐Moderate Canine Atopic Dermatitis: A Single‐Blind Randomised Study

ABSTRACT Background Canine atopic dermatitis (cAD) is a chronic allergic inflammatory skin disease that requires multimodal management. Allogeneic mesenchymal stromal cells (MSCs) have emerged as a potential therapeutic option. Objective To evaluate the efficacy and safety of an investigational allogeneic adipose‐derived MSC product (PK/CM‐1) in dogs with cAD. Materials and Methods Dogs with mild‐to‐moderate cAD were enrolled in a single‐blind, randomised study and allocated in a 2:1 ratio either to an experimental group (receiving a single intravenous dose of PK/CM‐1) or a control group (receiving three monthly subcutaneous doses of lokivetmab). Clinical outcomes were assessed using the Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI‐04) and pruritus Visual Analog Scale (PVAS) scores on Day (D)28 (primary end‐point) and D7, D56 and D84. Safety assessments included haematological and biochemical analyses on D84, along with monitoring for adverse events. Results Thirty‐two dogs were included. By D28, both CADESI‐04 and PVAS scores had significantly decreased from baseline in both groups. No significant differences between groups were observed on D28 ( p = 0.696 and p = 0.088, respectively). Clinical improvement was sustained up to D84. In the experimental group, CADESI‐04 and PVAS scores were lower on D84 than on D28 ( p = 0.0074 and p = 0.0015, respectively). Two adverse events (one severe and one mild) occurred during PK/CM‐1 administration. No clinically significant haematological or biochemical abnormalities were observed. Conclusions and Clinical Relevance PK/CM‐1 demonstrated comparable efficacy and safety to those of lokivetmab over a 3 month period. Careful monitoring is recommended during intravenous administration of PK/CM‐1.