Lifespan extension drug in development for senior dogs reaches a new milestone

A drug in development for healthy lifespan extension in senior canines has reached a new milestone on the path toward potential FDA approval. The conditional approval application for the drug LOY-002, created by Loyal, has had its’ Target Animal Safety (TAS) technical section accepted by the federal agency, according to the biotechnology animal health company.¹

The drug’s application has now received acceptance for 2 of 3 major technical sections required for market launch, according to Loyal.¹ The FDA Center for Veterinary Medicine previously granted the application a Reasonable Expectation of Effectiveness designation², and will need its’ manufacturing section accepted before conditional approval can be considered.

“As a veterinarian, what I care about most, especially when it involves preventive care, is safety,” Ellen Ratcliff, DVM, vice president of clinical and veterinary medicine at Loyal, said in a news release.¹ “The FDA’s sign off on this submission is an important vote of confidence in our mission to develop safe and effective lifespan extension drugs for dogs.”

Loyal anticipates the final major technical section to be reviewed in 2027.¹ Brennan McKenzie, VMD, MSc, MA, director of veterinary medicine for Loyal, said the mechanical section of LOY-002’s application is in progress. “Full approval would follow after completion of the STAY study, which is the pivotal effectiveness trial required to support a future full NADA [new animal drug application] approval,” he said in a dvm360 interview.

LOY-002 is a prescription daily pill that targets age-related metabolic dysfunction and is designed to improve quality of life in canines aged 10 years and older weighing at least 14 lbs.² “The metabolic dysfunction that all dogs experience as they age is a critical risk factor for many of the health problems that impact senior dogs. By improving metabolic health, we believe LOY-002 will extend not only lifespan but healthspan—the time that dogs are healthy and still able to enjoy their favorite activities and time with their human family,” McKenzie said.

The submission for TAS acceptance included evidence from several scientific investigations. “Among these was a safety study conducted at the standard 1x, 3x, and 5x dose strengths with no clinically significant adverse events observed at these doses,” McKenzie said. “Safety has been a central focus of LOY-002’s development from the outset. Preventive therapies that are prescribed to otherwise healthy dogs require a very high safety bar, and we are pleased that the FDA agrees that the data supports LOY-002’s safety for the proposed conditions of use.”

Scientific evidence also included the ongoing STAY study, which completed patient enrollment with 1300 dogs at 70 veterinary clinics across the US in July 2025.^1,3 “We evaluated field safety data from 400 dogs enrolled in the STAY study. The FDA then reviewed our submission and determined that LOY-002’s data supports the drug's safety for the proposed conditions of use,” McKenzie added,

“In both the standard safety study and the field data from STAY, a wide range of data were collected. The dogs were closely monitored, including regular examinations and laboratory testing,” McKenzie said. The data submitted to the FDA included information from dogs given LOY-002 for up to 1 year, and patients were included with a variety of ongoing medical conditions and other treatments commonly seen in senior dogs. The agency agreed that these data support the conclusion that LOY-002 is safe for its intended use.”

If LOY-002 is ultimately approved by the FDA, it would be the agency’s first drug approval for lifespan extension in any species, Loyal noted. As it stands, the drug received the first known safety acceptance for a lifespan extension drug from the FDA with the TAS support.¹

“Since founding Loyal 6 years ago, my goal has always been to get the first drug FDA approved for lifespan extension. This safety acceptance brings us very close to achieving that vision.” Celine Halioua, founder and CEO of Loyal, in a news release.¹ “We are well on our way to bringing the first dog longevity drugs to market.”

References

1. 1.Loyal receives FDA acceptance of safety package for senior dog lifespan extension drug. News release. Loyal. January 13, 2026.
2. 2.Crossley KC. Second drug for canine healthy lifespan extension receives FDA support. dvm360. February 26, 2025. Accessed January 13, 2026. https://www.dvm360.com/view/second-drug-for-canine-healthy-lifespan-extension-receives-fda-support
3. 3.Crossley KC. Clinical trial for longevity drug meets goal of enrolling 1000 dogs. dvm360. April 14, 2025. Accessed January 13, 2026. https://www.dvm360.com/view/clinical-trial-for-longevity-drug-meets-goal-of-enrolling-1000-dogs