[German Shepard. Photo Credit to Pixabay]

LOY-001, a potential lifespan-extending drug for large-breed dogs, received US Food and Drug Administration (FDA) acceptance for reasonable expectation of efficacy in November 2023. 

The drug was developed by Loyal, a San Francisco-based biotechnology startup founded in 2019 by entrepreneur Celine Halioua.

The drug is one of three in the company’s pipeline, by the codename: “LOY-001”, a long-acting injectable for large breeds; “LOY-002”, an oral medication for senior dogs of all sizes; and “LOY-003”, an oral treatment aimed at younger large dogs.

Dogs live much shorter lives than humans, and the difference is particularly evident in larger breeds.

Although smaller breeds live an average of 12 to 16 years, many large breeds survive only 8 to 10 years.

For pet owners, those few lost years mean a painful gap in companionship.

One reason large breeds live shorter lives is linked to Insulin-like Growth Factor 1 (IGF-1),  a hormone that regulates growth, development, and metabolism of all living animals. 

Having to grow in size much quicker than smaller breeds, larger breeds have higher levels of IGF-1, which accelerates both growing and aging.

Senior dogs often exhibit slowed movement, loss of muscle, and joint pain. 

To relieve such pain from both senior dogs and their parents, Loyal’s research seeks to address these changes with treatments tailored to different age groups and sizes.

LOY-001, the company’s leading candidate, is a long-acting injectable designed to extend the lifespan by reducing IGF-1 activity in large breeds.

In contrast, LOY-002 targets metabolic dysfunction in senior dogs of all sizes, including those as small as 14 pounds (6.4 kilograms).

Similarly, LOY-003 is aimed at younger dogs of 5 years and older, weighing 40 lbs or 18.1 kg and more, to reduce the over-expression of IGF-1 hormones.

The company has not finalized pricing but has suggested a “double digits per month” range to keep the treatment accessible for pet owners.

Like most preventative medications, safety continues to be a priority.

Reported side effects may include swelling or redness at the site of injection, mild gastrointestinal distress, loss of appetite, vomiting, diarrhea, and lethargy.

Loyal has submitted data from more than 400 dogs to the FDA to support its safety claims.

In addition to LOY-001’s regulatory progress in 2023, LOY-002 also received FDA acceptance for reasonable expectation of efficacy in February 2025.

Loyal aims to become a transparent company, with much of its progress and journals published on its website.

Despite the transparency, public reactions are mostly mixed, with many people welcoming the idea of extending their companion’s lifespan.

However, some also fear the monetization of the company in the future, fearing prices may rise once approval is secured.

With FDA decisions expected by 2027, many are watching to see if Loyal can keep its promises on both safety and affordability.