FDA grants conditional approval to targeted therapy for canine Chiari-like malformation and syringomyelia

The FDA has conditionally approved pregabalin chewable tablets (Liavium-CA1; TriviumVet) for the management of pain and clinical signs associated with Chiari-like malformation (CM) and syringomyelia in dogs.¹

The approval was granted to TriviumVet, an Ireland-based sponsor acquired by Pegasus Laboratories, Inc. in 2025, under the FDA’s conditional approval pathway, which is reserved for drugs intended to treat serious or life-threatening conditions, address an unmet animal health need, and for which demonstrating effectiveness requires complex or particularly difficult studies.¹

CM is a genetic condition in which a dog’s skull is too small for its brain, causing the cerebellum to protrude through the base of the skull.¹ This can restrict the flow of cerebrospinal fluid and lead to syringomyelia, a condition characterized by painful, fluid-filled cavities, or syrinxes, within the spinal cord that can expand and compress nerve fibers.^1,2 The most common sign is altered sensation, which typically affects the back of the head and neck and may progress to pain.²

Pregabalin, the active ingredient in Liavium-CA1, is designed to target nerve-related pain by reducing the release of neurotransmitters that transmit pain signals in the spinal cord.¹ The drug is administered orally twice daily with food and is available by prescription only, as veterinary oversight is required to diagnose CM and syringomyelia, determine appropriate dosing, and monitor for adverse reactions, according to the FDA.¹ Veterinarians may also recommend concurrent use of a nonsteroidal anti-inflammatory drug.¹

Dogs weighing less than 3 kg (6.6 lb) cannot be accurately dosed with Liavium-CA1.¹

“The conditional approval means the FDA has determined Liavium-CA1 is safe and has a reasonable expectation of effectiveness for its intended use,” the FDA wrote in an announcement.¹ The agency said TriviumVet has up to 5 years to generate the additional effectiveness data needed to support full FDA approval.¹

Prior treatment options for CM and syringomyelia have included neurologic medications such as gabapentin, as well as diuretics, antacids, and corticosteroids intended to reduce cerebrospinal fluid production.² Medical acupuncture has also been used as an adjunctive therapy.²

Clinical signs

Clinical signs associated with CM and syringomyelia can vary and are often progressive. Affected dogs may become withdrawn and may vocalize when jumping, running, defecating, or being picked up.² Intermittent pain, particularly at night, is also common.² Some dogs may develop difficulty walking or trouble with bowel movements because of increased intracranial pressure.¹

Sensitivity to touch around the shoulders, ears, back of the neck, or sternum is frequently reported. Another hallmark sign is phantom scratching, in which affected dogs appear to scratch while walking despite no obvious external trigger.² Some dogs may also rub their faces persistently.² Signs, including scratching or pain, may be triggered by touch, movement, excitement, or wearing a collar.²

Breeds predisposed to CM include Cavalier King Charles spaniels, Brussels griffons, Maltese, Yorkshire terriers, Chihuahuas, and pit bull terriers.²

References

1. FDA conditionally approves drug to control pain and clinical signs of Chiari-like malformation and syringomyelia in dogs. FDA. May 12, 2026. Accessed May 12, 2026. https://www.fda.gov/animal-veterinary/cvm-updates/fda-conditionally-approves-drug-control-pain-and-clinical-signs-chiari-malformation-and?utm_medium=email&utm_source=govdelivery
2. Weir M, Downing R. Syringomyelia and Chiari-like malformation. VCA Animal Hospitals. Accessed May 12, 2026. https://vcahospitals.com/know-your-pet/syringomyelia-and-chiari-like-malformation