The expiration of the conditional license has no effect on Masivet, an identical AB Science drug sold in Europe that carries the approval of the European Medicines Agency.

FDA issued a “Dear Veterinarian” letter to alert the U.S. profession about Kinavet.

“Kinavet-CA1 is an unapproved animal drug with no legal marketing status,” the letter stated. “You will no longer be able to legally obtain the drug.”

AB Science will alert veterinarians, too.

“As a company that takes its mission very seriously, we plan to be in close contact with not only our veterinary customers but also our distributor partners, all of whom we enjoy a great working relationship with,” Ahn said.

Mast cell canine patients may have other drug options, according to FDA.

“For example, the drug Palladia (toceranib phosphate, NADA 141-295), which is FDA-approved for the treatment of mast cell tumors in dogs, may be appropriate in some cases,” the agency stated. “Also, other FDA-approved animal and human drugs may potentially be used legally in an extralabel manner in dogs with mast cell tumors.”