FDA Issues Guidance on The Efficacy of New Heartworm Preventives

FDA has issued draft guidance to drug makers regarding the effectiveness of new heartworm prevention products for dogs.

Heartworm disease is a serious condition that can cause severe lung disease, heart failure, organ damage, and death in pets, most commonly dogs, cats, and ferrets. Dirofilaria immitis is a parasitic worm that causes this disease. Mosquito bites transmit the worms. Heartworm disease prevention is critical because heartworm disease treatment can have serious side effects in dogs and is expensive for pet owners.

The FDA issued a Federal Register notice in 2018 asking for feedback on potential alternative approaches for evaluating heartworm prevention products for dogs. In addition, the agency requested public input in response to reports of ineffectiveness and the limitations of effectiveness studies conducted to support product approval.

As previously stated, the sponsor should conduct two laboratory dose confirmation studies and one multisite field effectiveness study to demonstrate substantial evidence of the effectiveness of heartworm prevention products in dogs. The draft guidance makes specific recommendations on how to better assess effectiveness under actual use conditions and select heartworm isolates for laboratory studies.

The FDA issued a Federal Register notice on November 30, 2022, seeking feedback on the draft guidance. The deadline for public comment submissions is January 30, 2023.