Animal health biotech startup Loyal is a step closer to being able to market a drug for lifespan extension in dogs, the company said on Tuesday.

The U.S. Food and Drug Administration’s Center for Veterinary Medicine has approved the “Reasonable Expectation of Effectiveness” section of Loyal’s application to sell a new large- dog-focused drug called LOY-001.

“Four years ago I founded Loyal with a simple vision — to bring to market the first drug explicitly approved and labeled for healthy lifespan extension,” Loyal founder and CEO Celine Halioua wrote in a blog post. “Loyal was only a few months old and about five people when we decided to begin by targeting the abnormally short lifespan of large breed dogs with a drug program we code-named LOY-001.”


LOY-001 aims to extend the lifespan and quality of life in large and giant breed dogs, which may have as little as half the expected lifespan of small breeds, Loyal explained, noting Great Danes and Newfoundlands may live only eight years, compared to 20 years for Chihuahuas and Miniature Poodles.

The drug reduces Insulin-like Growth Factor 1 (IGF-1,) a hormone associated with growth and development in dogs that the company said is 28x more prevalent in large dogs than small dogs.

But Loyal's vision extends far beyond man's best friend.

"Dogs first to extend human lifespan," Halioua wrote on Twitter. "Save the dogs, save the world!"


"As there is no regulatory path for a lifespan extension drug, we had to design from scratch a scientifically strong and logistically feasible way to demonstrate [the] efficacy of an aging drug," she explained. "This took over four years, resulting in the 2,300+ page technical section approved today."

"I'm proud, still a bit shocked, and kind of feel like the dog that caught the mailman and doesn't know what to do now," Halioua continued. Fortunately, the FDA process is meticulous and strict.

For the LOY-001 canine drug, the next step would be to obtain FDA approval for Loyal’s manufacturing and safety data packages. After getting final FDA approval, Loyal said the drug could be available in 2026. Typically, FDA approval for a human drug can take up to fifteen years, delaying availability.

“Today’s milestone is a crucial part of Loyal’s application for conditional approval,” the company said in a statement. “It means the FDA agrees LOY-001 has a reasonable expectation of effectiveness.”

Launched in 2019 by Celine Halioua, San Francisco-based Loyal is a clinical-stage veterinary medicine company focused on extending the health and lifespan of dogs. In September 2021, Loyal announced the raise of $27 million in Series A funding led by Khosla Ventures. Other investors included First Round Capital, Box Group, Collaborative Fund, The Longevity Fund, and Lachy Groom, according to a 2021 Techcrunch report.

“Ever since we invested in Loyal in 2021, the team has made tremendous progress with the FDA, legitimizing an entirely new category of pharmaceuticals through their efforts,” Khosla Ventures Founder Vinod Khosla said. “Today’s announcement marks a first for any longevity drug, and is a big step towards accelerating the path for canines, and ultimately humans.”

Loyal confirmed to Decrypt that the LOY-001 drug itself has not yet been submitted. Instead, LOY-001 was introduced through the FDA’s Expanded Conditional Approval process, which gives the FDA authority to approve certain drugs meant for “minor species” like fish, ferrets, and dogs.

According to the company’s website, the next drug, LOY-002, will be launched for older dogs of all but the smallest breeds in early 2025. Loyal said the company is conducting clinical trials for LOY-002 for dogs ten years and older that weigh at least 14 pounds.


While humans may consider longevity medicine a potential fountain of youth, Loyal said LOY-001 is meant to not only extend the lives of dogs but also to correct centuries of human-driven dog breeding.

“The extreme phenotypic variety found in dogs is not ‘natural’ — it’s the result of intensive breeding by humans to create dogs that excelled at tasks such as herding, protection, and companionship,” Loyal’s Director of Veterinary Medicine Brennen McKenzie said. “At Loyal, we see the short lifespan of big dogs not as inevitable, but as a genetically-associated disease caused by historical artificial selection, and therefore amenable to targeting and treatment with a drug.”

Edited by Ryan Ozawa.

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