Drug for delaying congestive heart failure in dogs is approved by the FDA

Officials for the FDA have expanded its’ approval of pimobendan chewable tablets (Vetmedin; Boehringer Ingelheim) to include a new indication. The drug is now approved for delay of congestive heart failure (CHF) in dogs with Stage B2 preclinical myxomatous mitral valve disease (MMVD).

Heart disease affects approximately 10% of dogs in their lifetime, and MMVD accounts for about 75% of these cases presented at veterinary practices in North America.² Both MMVD and DCM may progress to CHF, according to BI. Canine patients with asymptomatic MMVD that have a moderate or loud mitral murmur caused by mitral regurgitation and cardiomegaly are considered to have Stage B2 preclinical MMVD.¹

Pimobendan chewable tablets was previously fully approved for the management of the signs of mild, moderate, or severe congestive heart failure in dogs caused by MMVD or DCM.³ The drug received conditional approved for the expanded indication in 2022, under the FDA’s authority for certain new animal drugs not intended for a minor use or minor species. According to the agency, this latest approval was the first time it granted a full approval of an animal drug indication that was initially conditionally approved under the agency’s expanded conditional approval authority.¹

A conditional approval is valid for one year with the potential for up to 4 annual renewals. After receiving conditional approval, the drug’s sponsor has 5 years to obtain full approval during which time active progress toward proving substantial evidence of effectiveness for full approval must be demonstrated. If full approval is not obtained in 5 years, the drug can no longer be marketed, according to the FDA.¹

Boehringer Ingelheim Animal Health USA generated the necessary effectiveness data to support a full approval and submitted a supplemental new animal drug application (NADA) for FDA review after 3 annual renewals for pimobendan chewable tablets, according to the FDA.¹ A pair of multisite field studies supported the company's NADA for the newly approved, expanded indication.⁴

The first study evaluated whether chronic oral administration of pimobendan chewable tablets could delay the onset of CHF in dogs with Stage B2 preclinical MMVD. The study enrolled 363 dogs owned by clients, with an effectiveness population of 353 dogs, of which 178 were treated with pimobendan chewable tablets and 175 were treated with a vehicle control, according to the FDA. The investigators’ final analysis showed a “statistically significant difference between the groups.” The median time to the primary endpoint for dogs in the pimobendan chewable tablets group was 1127 days vs 732 days for the control group, which represented a clinically significant delay in the onset of congestive heart failure.⁴

The second study was designed to further support the effectiveness of pimobendan chewable tablets in a subset of dogs with Stage B2 preclinical MMVD, which was defined by a left atrial-to-aortic root ratio (LA/Ao) of 1.8 or greater. This study enrolled 161 dogs owned by clients, with an effectiveness population of 125 dogs. All dogs in the study received pimobendan chewable tablets. Ninety-nine of the 125 dogs successfully completed the study without disease progression, and 26 dogs were classified as treatment failures because of CHF development, cardiac-related death or other advancing clinical signs. “The study's success criteria were met, as the lower bound of the 95% confidence interval for the success rate (70.3%) was well above the pre-specified threshold of 54%,” according to the FDA.⁴

In 2024, pimobendan oral solution for dogs was also approved by the FDA for management of signs of mild, moderate or severe canine CHF caused by MMVD or dilated cardiomyopathy (DCM). This product and pimobendan chewable tablets are both indicated for concurrent therapy use in treating CHF, on a case-by-case basis.⁵

References

1. FDA approves first drug to delay congestive heart failure in dogs. News release. FDA. December 19, 2025. December 22, 2025. https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-first-drug-delay-congestive-heart-failure-dogs?utm_medium=email&utm_source=govdelivery
2. Keene BW, Atkins, CE, Bonagura JD, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019;33(3):1127-1140. doi:10.1111/jvim.15488
3. Center for Veterinary Medicine. FDA conditionally approves first drug delay onset of congestive heart failure in dogs. FDA. June 16, 2022. Accessed December 22, 2025. https://www.fda.gov/animal-veterinary/cvm-updates/fda-conditionally-approves-first-drug-delay-onset-congestive-heart-failure-dogs
4. Freedom of Information Summary: NADA 141-273. FDA. December 19, 2025. Accessed December 22, 2025. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/17792
5. Crossley KC. Oral solution approved by FDA for canine heart failure. dvm360. November 22, 2024. Accessed December 22, 2025.