Elanco Launches FDA-Approved Zenrelia™ for Canine Dermatology

The U.S. Food and Drug Administration (FDA) has approved Zenrelia™, a new once-daily oral JAK inhibitor designed to treat pruritus (itching) associated with allergic dermatitis and atopic dermatitis in dogs aged 12 months and older. This announcement marks Elanco Animal Health Incorporated's entry into the $1.7 billion global canine dermatology market. Zenrelia's approval is based on its demonstrated efficacy and safety, offering a significant advancement in treating chronic, acute, or seasonal itching in dogs.

Elanco has highlighted the unmet needs in canine dermatology, noting that itching is one of the primary reasons pet owners take their dogs to veterinarians. Approximately 17 million dogs suffer from allergic skin diseases, including atopic dermatitis, food allergies, and flea sensitivity. Despite various treatments, many pet owners report that their dog's itch remains uncontrolled. A significant 60% of these owners have tried multiple treatments without success, underscoring the demand for effective solutions.

In a head-to-head noninferiority study comparing Zenrelia with Apoquel® (oclacitinib tablet), Zenrelia demonstrated its potential as an effective alternative. The randomized, double-blind study involved 338 client-owned dogs with confirmed atopic dermatitis across 25 sites in four countries. The study found that a daily dose of Zenrelia was at least as effective as the market-leading JAK inhibitor at the primary endpoint on Day 28. Furthermore, Zenrelia achieved clinical remission of itch in 77% of treated dogs, compared to 53% of dogs treated with Apoquel.

The study results also indicated that Zenrelia consistently provided greater relief from itch and skin lesions over time with once-daily dosing from the start. In contrast, dogs treated with Apoquel experienced rebound itch when dosing was reduced to once daily after Day 14. Both owners and veterinarians rated Zenrelia higher than Apoquel for overall treatment response from Day 28 to Day 112.

Veterinarians have expressed a need for more options in canine dermatology, with research suggesting that nearly 70% of veterinarians are open to stocking new dermatology products. Zenrelia addresses this need with its convenient once-daily dosing and affordability. The launch list price for Zenrelia is approximately 20% less for nearly all dogs compared to the current JAK inhibitor. Additionally, pet owners can expect even greater savings in the first 14 days due to Zenrelia's single daily dosage compared to twice daily.

A case in point from the clinical trial is Trooper, a one-year-old Yorkshire Terrier. When Trooper joined the trial, his itch level was at a maximum of 10 on the pruritus visual analog scale (PVAS). After two weeks of treatment, his itch level dropped to 1.9, and by the end of the trial, it reached 1.1, considered normal or clinical remission of itch.

Dr. Tom Lewis, a veterinarian and founder of Dermatology for Animals, participated in the Zenrelia field study and noted the need for more treatment options for itchy dogs. He reported seeing remarkable results during the study and expressed eagerness to start many patients on Zenrelia, highlighting the rewarding experience of seeing dogs return to normal and restoring the bond between pets and their owners.

The safety of Zenrelia has been well-documented through multiple toxicity and clinical safety studies. A margin of safety study involving healthy dogs dosed with varying amounts of Zenrelia for six months demonstrated no serious adverse events. However, the Zenrelia label includes a boxed warning concerning safety related to concurrent vaccine administration. In a vaccine response study, some dogs were immunosuppressed, leading to severe outcomes. Therefore, dogs should be up to date on vaccinations before starting Zenrelia, and veterinarians should read the entire package insert, including the boxed warning, before prescribing it.

Elanco is committed to providing clinically relevant data to guide treatment choices and plans to pursue additional studies to evaluate vaccine responses in Zenrelia-treated dogs. The company aims to continually improve the product label based on new findings.

Veterinarians in the U.S. can now place orders for Zenrelia, with shipments expected to begin in the coming days.