The FDA Approves Zenrelia, marking a significant breakthrough for dogs suffering from allergic skin conditions. On September 19, 2024, the U.S. Food and Drug Administration approved Zenrelia (ilunocitinib tablets), a new once-daily oral medication designed to control pruritus (itching) associated with allergic dermatitis and atopic dermatitis in dogs at least 12 months of age.
This approval represents the second JAK (Janus kinase) inhibitor approved by the FDA for canine dermatological conditions, providing veterinarians and pet owners with an additional treatment option for managing persistent skin allergies that affect millions of dogs nationwide.
How FDA Approves Zenrelia Works and what are Its Benefits
Zenrelia contains ilunocitinib, a non-selective JAK inhibitor that works by suppressing specific immune system pathways responsible for allergic reactions and inflammation. Unlike existing treatments that require twice-daily dosing, Zenrelia offers the convenience of once-daily administration, which can improve compliance and reduce the likelihood of missed doses.
Elanco Animal Health, the drug’s manufacturer, conducted extensive head-to-head studies comparing Zenrelia to the current market incumbent JAK inhibitor. Results published in the peer-reviewed journal Veterinary Dermatology demonstrated that Zenrelia was at least as effective as existing treatments while offering improved convenience and affordability.
The medication will be launched at approximately 20% less cost than comparable treatments, making it more accessible to pet owners seeking relief for their dogs’ chronic skin conditions. Bobby Modi, Executive Vice President of U.S. Pet Health at Elanco, emphasized that the once-daily dosing minimizes opportunities for rebound itching compared to twice-daily alternatives.
FDA Approves Zenrelia But What Are The Safety Information & Vaccination Concerns
Despite its effectiveness, FDA Approves Zenrelia carries a significant boxed warning regarding vaccination protocols. The FDA mandates that dogs should not receive vaccinations at least 28 days before and after treatment with Zenrelia due to the risk of fatal vaccine-induced disease and inadequate immune response to vaccines.
This warning stems from a vaccine response study where dogs treated with FDA Approved Zenrelia experienced drug-induced immune suppression, resulting in fatal complications including vaccine-induced adenoviral hepatitis and pancreatitis. Additionally, treated dogs showed inadequate immune responses to critical vaccines, including rabies, which poses both animal and public health concerns.
Dr. Mara Tugel, veterinarian and Dermatology Medical Strategic Lead at Elanco, acknowledged these concerns and confirmed that the company plans to pursue additional studies to evaluate vaccine responses in Zenrelia-treated dogs. She emphasized the importance of ensuring dogs are up-to-date on all vaccinations before beginning treatment.
Veterinarians must carefully consider each patient’s vaccination status and schedule when prescribing Zenrelia. The medication requires withholding for 28 days to 3 months before vaccination and at least 28 days afterward, making treatment planning crucial for maintaining both therapeutic effectiveness and vaccination protection.
The approval of Zenrelia addresses a significant unmet need in veterinary dermatology, as research indicates nearly 70% of veterinarians would be willing to stock another dermatology product. Many dogs with persistent allergic conditions continue to suffer despite existing treatments, and pet owners often struggle with the cost and complexity of current therapeutic options.
FDA Approves Zenrelia is available by prescription only in four tablet strengths: 4.8 mg, 6.4 mg, 8.5 mg, and 15 mg, offered in 10 and 30 count blister packages and 90 count bottles. Elanco has begun taking orders for the medication, with shipping expected to commence within days of the FDA approval announcement.
This development represents a significant advancement in companion animal healthcare, offering new hope for dogs with chronic allergic skin conditions while requiring careful management of vaccination protocols to ensure optimal patient safety.