Researchers from Syntrix Biosystems, Inc. and The University of Medicine and Dentistry of New Jersey announced today that there was no evidence of Aminopterin in the tissues of animals who had died from consuming food from Menu Foods, the manufacturer of the many brands of dog and cat food that are currently the subject of a nationwide recall.

"We became concerned when Aminopterin was implicated as the toxin in the recent pet food recall. The clinical pattern did not fit the known toxicology of Aminopterin," said John A. Zebala, M.D., Ph.D. President and CEO of Syntrix Biosystems, which claims there was no evidence of Aminopterin in the tissues of affected animals.

"Aminopterin persists in the liver of animals for months at levels that are readily detected," said Barton A. Kamen, M.D., Ph.D. Professor of Pediatric Oncology at UMDNJ. "Whatever is causing the renal failure, it is not Aminopterin."

These results are consistent with the findings of the FDA, who announced today that they found no evidence of Aminopterin in food samples.

The reference to the use of Aminopterin as a rodenticide, or rat poison, dates back to a 1951 patent issued to the American Cyanamid Company that is commonly cited by a variety of reference textbooks including the Merck Manual.

"To our knowledge, Aminopterin is not, and has never been, actually used as a rodenticide. The preparation of the molecule is complex and expensive. It is also unstable in the environment due to degradation by light and heat," said Dr. Zebala.

Syntrix Biosystems and Dr. Kamen are clinically testing Aminopterin in pediatric leukemia and plans to market Aminopterin for the treatment of inflammatory and oncology disorders in both veterinary and human markets. "Many patients have been treated for over 2 years with Aminopterin and are disease free after 5 years," Dr. Kamen says, adding that Aminopterin was used to safely treat over 4,000 patients with psoriasis in the United States, producing dramatic clearing of lesions. According to researchers, Aminopterin may be used in treatment of human autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus, polymyositis, multiple sclerosis, ulcerative colitis and Crohn's disease to name a few.