By Ronnie Cohen
(Reuters Health) - - A consortium of animal-welfare groups has funded research to develop a product it says could lead to more effective treatment of infectious diphtheria in humans while sparing thousands of horses now being bled to produce antitoxins.
The PETA International Science Consortium conceived the deal, signed last week, to try to get horses out of the antitoxin business. Many live on farms in India, where veterinarians last year found them neglected, mistreated and in pain, some blind, lame, anemic, standing in their own waste and so malnourished that their ribs poked through their coats, according to a report from People for the Ethical Treatment of Animals, India.
The worldwide consortium of PETA groups awarded 134,000 euros (about $142,000) to Technical University Braunschweig in Germany to pioneer a new treatment for diphtheria, a bacterial infection. The human antitoxin would be grown with human cells in a test tube, instead of being drawn from the blood of horses.
“It’s better for the people and also for the horses,” Professor Michael Hust of Technical University said in a telephone interview. He will lead the research to replace equine serum with human serum.
Stocks of the equine antitoxin have become increasingly difficult to locate, and those who receive it sometimes experience reactions similar to anaphylactic shock, Hust said.
He expects a serum made from recombinant human antibodies will provide a higher quality, more uniform product with fewer side effects and a longer shelf life.
Dr. Stephen Hadler, deputy director of the division of bacterial diseases at the U.S. Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases, welcomed news of the PETA deal. He is not involved in it.
“A product that’s made with human antibody, as opposed to horse antibody, would be a good idea, assuming it’s been appropriately tested and it’s as effective,” he said by phone. “It’s good to hear this group is willing to support it.”
Human antitoxin is less likely to produce allergic reactions than horse antitoxin, Hadler said.
“This is an area where the human health interest is completely interwoven with horse welfare,” Jeffrey Brown, a biologist and advisor to the PETA consortium, said in a telephone interview.
“Antitoxins made from horses aren’t the best for humans,” Brown said. “We have a shortage of a bad product. We need a better product that we can produce more reliably.”
“Antitoxins are lifesavings drugs, but the way they’re manufactured hasn’t kept pace with science,” Brown said.
Treatment for diphtheria has remained the same for more than 100 years, since the late 1890s, when Dr. Emil von Behring conceived the approach of using immunized animal blood to treat the disease – work for which he won the first Nobel Prize in Physiology or Medicine in 1901.
To make the equine antitoxin, horses are repeatedly injected with diphtheria toxins, their immune systems develop antibodies against the bacteria, and the antibodies are extracted from their blood.
Diphtheria once was one of the most common killers of children. In 1921, the U.S. recorded 206,000 cases and 15,520 deaths, according to the Centers for Disease Control and Prevention. Since then, mass vaccination has largely eradicated diphtheria, though outbreaks persist, including a recent one in Venezuela.
The World Health Organization reported 4,778 cases last year.
Public health authorities have been calling for a better supply of antitoxin for years, Brown said. But pharmaceutical companies have not been investing in diphtheria antitoxin research because affected regions generally can ill afford to pay for the cost of developing drugs.
The PETA consortium’s grant to Hust will last for three years. Hust believes it will take at least another 10 years of clinical trials before a human antitoxin is available for people with diphtheria.