Canine osteoarthritis drug, Lyme disease bacteria vaccine receive approvals

Two recent drug approvals mean a novel treatment for the control of canine osteoarthritis (OA) pain and an oral vaccine against the wildlife spread of Borrelia burgdorferi, the bacterium responsible for Lyme disease, will soon hit the market.


On May 5, the Food and Drug Administration (FDA) approved Librela, for the control of canine OA pain in the U.S. The first and only injectable monoclonal antibody (mAb) treatment for canine OA is expected to be available in late 2023.

A once-monthly injection administered by a veterinary professional, Librela (bedinvetmab injection) works differently than other pain medications, according to a May 5 release from Zoetis. It targets nerve growth factor (NGF) to control canine OA pain. Librela functions like naturally produced antibodies and is metabolized and eliminated via normal protein degradation pathways with minimal involvement of the liver or kidneys, according to the company.

Librela is approved as safe and effective in providing long-term control of osteoarthritis pain symptoms in dogs, which can improve their mobility and overall quality of life. (Image courtesy of Zoetis)

A diagnosis of osteoarthritis in a pet can be unwelcome to the veterinarian as well as the pet owner because the disease is painful and progressive. OA affects more than 20% of dogs and is the most common cause of lameness in dogs older than 1 year, according to recent studies. This prevalence is significantly increased in senior patients, increasing to almost 80%.

The most common clinical signs of OA in dogs include pain and lameness. Over the last decade, there have been a number of advances in the treatment options available for dogs with OA, as well as an increasing number of clinical trials investigating the efficacy of pre-existing treatments, according to a 2022 study in the Journal of Small Animal Practice. These include monoclonal antibodies, piprants, adjunctive analgesics, structure modifying osteoarthritis drugs, and regenerative therapies.

In two field studies, dogs administered Librela as a monthly injection demonstrated a reduction in OA pain compared to dogs that received the placebo. “While effectiveness may not be seen until after the second dose of Librela, some dogs may experience a reduction in pain as early as seven days after the first dose,” the release stated.

Additionally, in a continuation study, dogs treated with Librela experienced lasting OA pain relief over the course of the study with monthly injections. The most common adverse events reported in dogs treated with Librela included urinary tract infections, bacterial skin infections, and dermatitis.

Only two of the Librela-treated dogs in the study had elevated blood urea nitrogen (BUN), both of which had comorbidities, with an elevation in other renal parameters. For the vast majority of dogs, according to a Zoetis spokesperson, an increase in BUN was not associated with clinical signs or changes in other renal parameters. There was also no evidence of a gastrointestinal bleed in any of these dogs.

The FDA approved a monoclonal antibody for cats on January 13, 2022, which was the first mAb new animal drug approved by the FDA for use in any animal species and the first treatment for the control of pain associated with OA in cats.

Borrelia Burgdorferi Bacterin

In addition, the U.S. Department of Agriculture has granted a conditional license to an oral vaccine against the wildlife spread of Borrelia burgdorferi, the bacterium that causes Lyme disease, the number one vector-borne disease in the U.S.

A worm-like, spiral-shaped bacterium, Borrelia burgdorferi is carried and transmitted primarily by the blacklegged tick known as the deer tick. The tick is infected primarily by feeding on small wildlife mammals, particularly white-footed mice. The vaccine from US Biologic Inc., is called Borrelia Burgdorferi Bacterin and is spray-coated onto pellets that the mice consume. The product, called LymeShield, includes a device or “station” that holds and applies the pellets, according to the company’s website.

White-footed mouse
The vaccine Borrelia Burgdorferi Bacterin is meant to prevent against the wildlife spread of the bacterium responsible for Lyme disease. Borrelia burgdorferi is carried and transmitted primarily by the blacklegged tick known as the deer tick, which is infected primarily by feeding on small wildlife mammals, particularly white-footed mice.

US Biologic will provide the product in residential settings; public lands, including parks; and commercial areas, such as golf courses and other recreational facilities, according to a May 9 press release. The company added that it will work closely with federal and state health agencies and pest management professionals that service the areas most at risk for infection, as well as partners such as the Global Lyme Alliance and the Lyme Disease Association, Inc.

The geographic distribution of infected ticks has expanded because of bird migration, suburban sprawl, and climate changes, according to 2018 American College of Veterinary Internal Medicine (ACVIM) consensus update on Lyme borreliosis in dogs and cats.

Field trials demonstrating real-world impact have been conducted and co-published by the Cary Institute of Ecosystem Studies, the Centers for Disease Control and Prevention (CDC), the Connecticut Agricultural Experiment Station (CAES), the University of Pennsylvania, and others.

“Lyme disease and other tick-borne diseases present a tremendous public healthcare challenge,” said Scott Williams, PhD, chief scientist and department head at the CAES, which performed field trials showing the positive impact of the vaccine in residential settings in Redding, Connecticut. “We need to continue to support efforts to innovate and provide these types of new tools.”

Ticks infected with Borrelia burgdorferi feed on humans, pets, and other animals transmitting Borrelia, which causes Lyme disease, experienced as severe damage to joints, neurologic systems, and the heart. The CDC estimates that 476,000 people in the U.S. are diagnosed with and treated for Lyme disease annually.

A version of this story appears in the July 2023 print issue of JAVMA.