BY: SAMANTHA BARTLETT, DVM

The Food and Drug Administration (FDA) granted conditional approval in June to expand the use of Pimobendan to delay the onset of congestive heart failure in dogs with preclinical myxomatous mitral valve disease. Since 2007, Pimobendan has been approved to manage clinical signs of congestive heart failure caused by dilated cardiomyopathy or atrioventricular valvular insufficiency.

Conditional approval means that the FDA believes the drug has a reasonable expectation of effectiveness and safety. The conditional status will allow Boehringer Ingelheim Animal Health USA to market a drug while the FDA collects efficacy data for full approval. The approval is valid for one year but can be renewed up to four times. Boehringer has five years to obtain full approval for the new indications. Boehringer will market pimobendane under two names: Vetmedin for the original indications with full approval and Vetmedin-CA1 for the conditionally approved indications. Both labels will have the same active ingredient at the same dosages.

The effectiveness of Vetmedin-CA1 was determined in a long-term study in client owned dogs with cardiomegaly. Dogs were either given Vetmedin or a placebo with no active ingredient. The median time from starting treatment to an endpoint of left-sided congestive heart failure, death or euthanasia due to cardiac disease. The duration was 15.6 months longer in the Vetmedin-CA1 group than the control group. The guidelines for implementation of Vetmedin-CA1 are delineated in a 2019 ACVIM Consensus Statement for Stage B2 MMVD (https://pubmed.ncbi.nlm.nih.gov/30974015/).