When the US Food and Drug Administration (FDA) goes after pharmaceutical companies for violating federal marketing regulations, it usually goes after makers of pharmaceuticals for humans. But as a recent and rare Warning Letter illustrates, sometimes veterinary companies fall under the agency's scrutiny as well.

In a 2 April 2014 letter to AB Science, a French pharmaceutical manufacturer, FDA veterinary regulators cited the company for allegedly marketing its veterinary product Kinavet using off-label, unapproved claims.

The drug is conditionally approved to treat canine mast cell tumors (Grade II or III) that have not been previously treated with chemotherapy.

However, according to several promotional materials cited by FDA, the company is in effect suggesting that the drug is effective "for a broader range of indications than are described in the approved labeling."

For example, FDA regulators reviewed the company's website, where they found a statement that said the drug is "potentially well-suited for treating non-oncology diseases, such as canine atopic dermatitis or feline asthma," and added that this was backed up by "off-label use" of the drug in several case studies.

In a separate document posted on the company's website, AB Science claimed that "a picture is worth 1000 words" when highlighting the use of Kinavet on canine atopic dermatitis. The same document also noted that the drug is being investigated in a "wide range of other cancers and immune-mediated disorders." A third document cited by FDA, a detailer posted to the company's website, made similar note of potential off-label uses of the drug, FDA said.

In all, the three claims constituted evidence that the drug "is intended for new uses for which it lacks approval … making Kinavet-CA1 an unapproved new animal drug for those uses," FDA wrote, explaining that AB Science was in violation of Section 512(a) of the Federal Food, Drug and Cosmetic Act (FD&C Act).

FDA called its evidence "particularly compelling" given Kinavet's conditional approval, which explicitly prohibits a company from allowing its drug to be used outside of its approved labeling (known as extra-label use). The drug was approved based on an interim endpoint, time to progression (TTP).

FDA's Center for Veterinary Medicine (CVM) also chided the company for failing to include several important statements about the drug's safety and efficacy on its website and in its materials. For example, the company reportedly failed to include information that people should not come into direct contact with the drug due to its potential to cause birth defects and other problems. Other omitted information included caveats on the drug's effectiveness and its side effects, contraindications and potential to cause life-threatening adverse events.

FDA said AB Science should "immediately cease" marketing its products using the materials cited in the agency's Warning Letter.

Warning Letter to AB Science