AVMA News

FDA issues guidance on effectiveness of new heartworm preventives

December 13, 2022

The Food and Drug Administration has issued draft guidance for drugmakers regarding the effectiveness of new heartworm prevention products for dogs.

In 2018, the FDA published a Federal Register notice requesting input on possible alternative approaches for evaluating heartworm prevention products for dogs. The agency asked for public input because of reports of lack of effectiveness and the limitations of the effectiveness studies conducted to support product approval.

Hand feeding pet dog with chewable to protect from heartworm


As before, the recommended approach to demonstrate substantial evidence of effectiveness for heartworm prevention products in dogs is for the sponsor to conduct two laboratory dose confirmation studies and one multisite field effectiveness study. The draft guidance provides specific recommendations how to better assess effectiveness under actual conditions of use and select heartworm isolates used in laboratory studies.

On Nov. 30, the FDA published a Federal Register notice seeking input on the draft guidance. The deadline for comments is Jan. 30.