Japanese Drug Blocks AIDS Virus in Lab Tests

A drug that can be purchased over the counter in Mexico and Japan has been shown in laboratory tests to be a potent agent against the AIDS virus, a group of National Cancer Institute researchers report.

The drug, called dextran sulfate, was found to prevent the AIDS virus from infecting and killing the body’s T-cell lymphocytes, the main target of the virus, a researcher said Thursday.

One member of the research team cautioned, however, that the results are still in the test-tube stage and it is unknown how effective the drug may be in actual use with humans.

A spokesman at NCI said dextran sulfate is now being tested in clinical trials at San Francisco General Hospital. Results are expected to be announced at an international AIDS meeting in Stockholm in June.

“We found in the test tube that this agent is a very powerful inhibitor of the HIV virus,” said Dr. Flossie Wong-Staal, an NCI researcher and co-author of a study on dextran sulfate. HIV, human immunodeficiency virus, is the virus that causes acquired immune deficiency syndrome.

A report on the laboratory testing of dextran sulfate was published in the magazine Science. In addition to Wong-Staal, the co-authors of the report are Drs. David J. Looney, Samuel Broder and Hiroaki Mitsuya, all of NCI, and Sachiko Kuno and Ryuji Ueno of Ueno Fine Chemicals of Osaka, Japan.

Ueno now holds a patent for use of the drug against AIDS.

Wong-Staal said the drug has been used for more than two decades in Japan and elsewhere as an anti-coagulant and has demonstrated that it has no significant toxicity.

“This drug may be very promising against AIDS,” said Wong-Staal, “because it is already in use and because it has been shown to be very potent against HIV-1 and HIV-2 (two viruses that cause AIDS).”

Wong-Staal said the drug most likely will be used with other drugs in a powerful combination to block replication of the AIDS virus.

But she said it must undergo trials before it is ready for general use.

Her co-investigator Broder cautioned: “This is not a breakthrough.”

He said that although the drug “is a potent agent against HIV-1 and HIV-2” in the test tube, it is not at all clear that the drug can be given to AIDS patients in sufficiently strong doses to affect the course of the disease in the body.

Broder said dextran sulfate is only one of a large family of potential antivirals that must first undergo carefully controlled trials.

Dr. Robert Gallo, an NCI researcher and co-discoverer of the AIDS virus, said dextran sulfate should be studied further.

“I’m impressed by the results I’ve seen in vitro and it merits trials (in patients),” he said. “The question is, will it be able to be taken by patients for long periods of time?”

Wong-Staal said the drug prevents the HIV virus from invading the T-cell lymphocytes, a type of immune cell that the AIDS virus normally attacks.

The HIV virus attacks the T-cells by first attaching to a receptor, a type of protein, on the cell’s outer layer or envelope. In the lab studies, dextran sulfate was found effective in preventing the virus from binding to the cell envelope, thus preventing it from invading and killing the cell.

Untreated, HIV changes the genetic pattern of the T-cell and forces it to start making copies of the virus. But this cannot take place if the virus cannot invade the cell.

The drug was first formulated by Ueno Fine Chemicals. It was used for decades as an anti-coagulant to treat blood clots, but has not been approved for that use in the United States by the Food and Drug Administration. The drug can be purchased over the counter in Mexico and in Japan, however.

As of April 21, AIDS had been diagnosed in about 59,500 Americans, of whom more than half, or about 33,000, have died since June, 1981, according to the federal Centers for Disease Control.