Studies in humans of a novel class of antibiotics based on an infection-fighting protein discovered in a frog's skin could begin this fall, researchers said Saturday, saying the drug may be the first of a new wave of drugs from animals.
"What we have in the frog is just a tip of what we have yet to discover," Dr. Michael Zasloff, a University of Pennsylvania professor of pediatrics, told the 18th World Congress of Dermatology in New York.Zasloff's discovery that a frog has its own internal "disinfectant," first published in 1987, has led to the creation of new compounds called magainins.
He told the conference that other researchers have found similar internal infection-fighting molecules in pigs, horseshoe crabs, mice and, more recently, humans.
"We will be reporting very soon that the human gut has antibiotic-secreting structures," Zasloff said.
He said one of his colleagues at the university, Charles Bevins, will soon publish his findings that certain cells in the human stomach contain antibiotic peptides.
While these more recent discoveries are far from leading to a new drug, Zasloff's research on frogs and magainins has resulted in one chemically synthesized drug.
A tiny company called Magainin Pharmaceuticals Inc. was founded in Plymouth Meeting, Pa., and is developing magainins into commercial drugs.
Leonard Jacob, executive vice president of research, said the company had chemically synthesized amino acids discovered in the frog's skin after 2,000 attempts to chemically imitate the protein.
He said the company will seek U.S. regulatory approval to begin human studies of the drug, MSI-78, this fall.
MSI-78 is being studied initially as a topical treatment for infections including diabetic ulcers, bedsores and leg ulcers. Researchers said magainin compounds also have potential as anti-tumor agents in various cancers, including ovarian, but those studies are in early stages.
Zasloff said he discovered the frog protein accidentally while he was a researcher with the National Institutes of Health.
He said other scientists are studying the potential of antibiotic substances excreted from plants.