EntreMed Inc., which already had patent protection for its anti-cancer protein Endostatin, said yesterday that the government has issued a broader patent protecting the company from competitors developing therapies using other flagments of the same protein.
"We were very, very keen to see this patient issued because we knew there were other researchers" developing drugs from the Endostatin protein, said Joanna Horobin, the company's senior vice president for commercial development.
The EntreMed drug is a fragment of that protein.
"Potentially, these could have been developed as molecules that threatened Endostatin itself," she said.
Endostatin is a naturally derived protein that has been shown to block the growth of blood vessels in animals.
The patent, issued Jan. 16 but not publicized until yesterday, is owned by Children's Hospital in Boston but has been licensed exclusively to EntreMed.
Rockville based EntreMed knows that a number of academic and corporate researchers, including those at Ilex Oncology Inc. In San Antonio, have looked, at. using other portions of the protein a regulate the blood-vessel growth associated with disease, Horobin said.
Jill Scoggins, an Ilex spokeswoman, said none of that company's experimental drug candidates appear to infringe the Endostatin patent.
Endostatin is the best known of three anti-cancer drugs discovered at Children's Hospital to stop the growth of tumor-feeding blood vessels.
Besides Endostatln, the other two drugs undergoing tests in human cancer patients are Angiostatin and 2ME2.
But the process of blood vessel growth Known as angiogenesis, also has implications for treating the eye, arthritis and heart disease. EntreMed, which has dubbed itself "the angiogensis company" eventually may test anti-angiogenic drugs for treating other illnesses.
With the issuance of the broader patent, EntreMed has protection for any fragment of the Endostatin protein developed to treat disease by arresting blood-vessel growth, said Mary Sundeen, a company spokeswoman.
"Whether it's cancer, heart disease or arthritis, the patent converage belongs to EntreMed," she said.
Some researchers are testing biologics that treat heart disease by encouraging blood-vessel growth.
But some researchers have shown that the plaque built up in arteries contains tiny blood vessels, suggesting that anti-angiogenic drugs could be used to control the buildup by blocking blood vessel growth.
"If you take (arterial) plaque, it's full of blood vessels," said EntreMed patent attorney Jim Johnson. That means anti-angiogenic agents might be of use in heart disease as well.
"This patent has enabled us to include our preclinical program to include a variety of collagen-derived anti-angiogenic molecules as we continue our aggressive clinical studies in cancer patients," said John W. Holaday, EntreMed, chairman and chief ececutive.
Shares of EntreMed fell $1.00 nearly 4 percent, to close at $24.75 on the NASDAQ stock market yesterday.