What Does It Mean When a Drug is “Conditionally Approved” by the FDA?

Q&A with Anivive’s Dr. Steve Sutherland on Conditional Approval

November 19, 2021
3 min read

Article Highlights

  • Conditionally approved animal drugs are just as safe as fully approved animal drugs.

  • The FDA grants conditional approval of an animal drug based on their review and concurrence with an extensive body of data provided by the company (the drug sponsor).

  • Following conditional NADA approval of an animal drug, a drug sponsor is given five years to collect the remaining effectiveness data required for full NADA approval; if such data is not provided, conditional approval status for the NADA is rescinded and the product can no longer be marketed.

  • Drugs qualify for conditional approval if they are intended for Minor Use and/or Minor Species (MUMS) indications.

This article is the second in a series exploring veterinary drug and vaccine regulations. For this installment of the series, we sat down with Anivive’s Chief Regulatory Affairs Officer, Stephen Sutherland, DVM, to ask him some questions about conditionally approved drugs.

Could you begin by explaining what conditional approval of an animal drug is?

Before an animal drug product can be legally marketed for use in animals, a New Animal Drug Application (NADA) for the drug must be approved by the FDA. If the proposed drug product meets certain qualifications, the FDA may provide a company with the option of seeking a conditionally approved NADA. FDA requirements for a conditionally approved NADA are identical to a fully approved NADA except for the effectiveness section of the NADA which has reduced data requirements. Although data requirements to demonstrate effectiveness are reduced for a conditionally approved NADA, it is important to note that a significant body of evidence is still required to establish a reasonable expectation of the product’s effectiveness. NADA requirements to establish safety, and to fulfill manufacturing and product quality standards, are the same for a conditionally approved NADA and a fully approved NADA.

The ‘conditional’ part of conditional NADA approval indicates that the drug sponsor (company) has the responsibility to, within five years, generate the additional effectiveness data required to fulfill the FDA’s ‘substantial evidence’ standard for full NADA approval. If the drug sponsor fails to gather this evidence within five years, conditional approval status of the NADA is lost, and the drug product can no longer be marketed.

Conditionally approved drugs are designated by the abbreviation “-CA1” after the drug name.

Are all animal drugs eligible for conditional approval? What drugs can seek conditional approval?

Very few animal drug products are eligible for conditional approval. The conditional approval category is restricted to drugs that are intended for treatment of disease indications that are uncommon or designated for use in a ‘minor species’ (such as a ferret). The FDA program that governs the decision for conditional approval designations is the Minor Use/Minor Species (MUMS) program. Minor use is a calculated numerical threshold of patients in which the disease indication of the proposed product is likely to occur that cannot be exceeded. If the expected disease incidence is above that threshold, the indication is considered to be a major use and does not qualify for a MUMS designation and conditional approval cannot be pursued. Minor species are non-human species that are not considered to be a major species, such as a dog or cat. There is an in-depth explanation of these terms on the FDA’s website.

That sounds like a lot to be unpacked. Aside from the extent of the drug’s usage, how are conditionally approved animal drugs different from fully approved drugs?

In terms of the FDA regulatory requirements, there’s little difference between a conditionally and fully approved NADA. Requirements for demonstration of safety and manufacturing quality are the same.

Does the lack of sufficient evidence mean that conditionally approved drugs are any less safe than fully approved drugs?

No. Although additional data are required to the fulfill the effectiveness standard for full NADA approval, FDA’s approval of a conditionally approved product demonstrates that all NADA requirements for safety and manufacturing have been fulfilled. Additionally, the FDA grants conditional approval based on data that demonstrates that the product’s formulation is manufactured in a manner that ensures that the product will be safe and effective when used as directed in the product’s labeling.

That’s reassuring to hear. Hearing your insight has been really helpful today. Thank you for your time!

Thank you for inviting me. It was great to share my knowledge with you.