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Tustin Company Thinks New Drug Could Target Cancer and Multiple Viruses

Posted on: Saturday, 16 July 2005, 00:00 CDT

Jul. 16--What if someone told you they had a drug that could fight cancer and nearly every human virus from HIV to hepatitis C, and from Ebola to the common flu?

You might be a little surprised, a little curious, a little excited -- and more than a little incredulous.

But Peregrine Pharmaceuticals, a small Tustin company, is making a big bet on a new drug that it says could be just such a panacea.

The drug, Tarvacin, is in the early testing stages. So far, it has shown promising results against cancer in mice and against at least two viruses, including one that causes a kind of hemorrhagic fever related to the deadly Ebola.

Peregrine recently received federal approval to begin initial testing of Tarvacin in humans for solid tumors and for hepatitis C. It's also being tested at lower trial levels -- not on humans -- against the HIV virus, which causes AIDS, and many others.

A government agency recently asked Peregrine for permission to test the drug against some 30 viruses considered to be potential agents of bioterror. The company hopes those tests could lead to early approval of Tarvacin for use in the case of a bioterror attack -- a move that would make the drug an earner before it got formal approval from the U.S. Food and Drug Administration for wider distribution.

Executives at Peregrine know it's still early. But they think -- and hope -- that they might just be on to something big. When they ponder the best-case scenario, they get stars in their eyes -- and more than a few dollar signs.

"This could be the biggest science discovery of my lifetime if it works against all these viruses and cancer at the same time," says Paul Lytle, Peregrine's chief financial officer. "If you went out and tried to develop vaccines for all these viruses, it could take hundreds of years." When Lytle and his colleagues think of role models, they point to Genentech Inc. in South San Francisco, whose pioneering anti-cancer drug Avastin has posted sales of $640 million since its approval early last year.

"You want to model yourself on the people who have been successful," says Steven King, Peregrine's chief executive officer. If the early claims about Tarvacin are borne out, he sees no reason Peregrine couldn't be catapulted from money-losing research mode into the pharmaceutical big leagues.

"I see that as a way the market has actually responded to a product such as the one we're developing," King says. "I think Tarvacin represents what could be termed a blockbuster type drug." Scientists who are working on the drug with Peregrine are also excited, but they urge caution. They warn that hypotheses often crumble in the laboratory for reasons that weren't even imagined beforehand -- and that tests in humans don't always turn out the way they did in animals.

"There are no guarantees, but it's an interesting idea and it looks promising," says Preston A. Marx, a virologist at the Tulane University Primate Center in Covington, La., who's working as a paid consultant to Peregrine. "There's a lot of additional work until you realize this." Philip E. Thorpe, a professor of pharmacology at the University of Texas Southwestern Medical Center in Dallas and a paid Peregrine consultant -- whom executives at the company call "the father" of Tarvacin -- notes that recent tests of the drug in mice have shown almost complete abolition of cancer growth and metastasis. But "we need to demonstrate efficacy in humans," he says.

The reason Tarvacin appears to have such a broad range of uses is that it targets not any specific cancer or virus, but rather a substance found in the membranes of all cells. When cells become malignant, or are infected by a virus, the substance -- known as a phospholipid -- moves from the inside of the membrane to the outer surface, allowing Tarvacin to bind with it.

The binding marks the cell, raising a red flag that alerts the immune system to the presence of a foreign body. With viral infections, the body's white blood cells attack the viruses. With cancer, the immune system appears to destroy the blood vessels of a tumor, depriving it of the nutrients it needs to grow.

"The concept is almost so simple it's hard to believe no one picked up on it before," says King, the CEO.

In cancer, Tarvacin might prove particularly effective in combination with chemotherapy and radiation, Thorpe says. That's because those more traditional treatments appear to enhance the movement of phospholipids to the surface of the membrane, giving Tarvacin a bigger target.

Scientists say Tarvacin could have an advantage over other anti-viral drugs, because viruses probably won't be able to evade it by mutating.

"Mutation won't affect it because it's targeting a substance which is not intrinsic to the virus itself but to the host cell -- so that substance will be there no matter what new form the virus takes," says Stephen M. Smith, a paid Peregrine consultant and chief of infectious diseases at the Seton Hall school of Graduate Medical Education in New South Orange, Jersey.

Peregrine executives say that even if Tarvacin doesn't pan out, there are still other lines of business that could help make the company profitable.

They are fairly far along with testing of Cotara, a drug that has shown some effectiveness against a certain type of brain tumor. And they receive royalties from the licensing of intellectual property to other, more established drug firms.

In addition, Peregrine's wholly owned manufacturing subsidiary, Avid Bioservices, has a contract to produce an eye drug for another company -- a deal that could mean significant new revenue.

But clearly, Tarvacin is the 800 pound gorilla in Peregrine's board room these days. And while company executives soak in the headiness of a potentially revolutionary new discovery, the scientists are whispering in their ears a mix of excitement, caution and good old-fashion scientific curiosity.

"I don't know where it's going to lead us, but the approach is clearly unique," says Seton Hall's Smith. "As I tell my fellows, empiricism rules.

But from a theoretical point of view, it's really fun to think about."

PEREGRINE PHARMACEUTICALS INC.

Headquarters: Tustin

CEO: Steven King

2005 revenue: $5 million

2005 net loss: $15.5 million

Stock price: $1.00

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PPHM, DNA,

Source: The Orange County Register

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