New AIDS Drug Called Promising

An experimental AIDS drug has shown early promise in delaying the onset of the deadly disease in some patients who are infected with the AIDS virus but have not yet developed severe symptoms, a California pharmaceutical company said today.

Because acquired immune deficiency syndrome is invariably fatal once it develops, any drug that may postpone the onset of the disease understandably causes excitement among those at risk.

But officials of ICN Pharmaceuticals of Costa Mesa cautioned during an unusual press conference that the drug, ribavirin, is not a cure for AIDS and has not been proved to prevent the disease.

Not Enough Evidence

“We don’t have enough evidence to say ribavirin prevents AIDS,” said Dr. Karl Johnson, ICN’S vice president for medical affairs. “The drug may delay the onset of AIDS for at least seven months. . . . But it will not surprise me if some of the patients (who are well today) eventually come down with AIDS.”

The test data is potentially significant for the 1 million to 2 million Americans estimated to be infected with the AIDS virus and millions of additional infected persons throughout the world. All of them might benefit from a medicine that could delay the onset of more serious AIDS-related illnesses.

The six-month study involved 163 homosexual men infected with the AIDS virus, divided into three test groups. All of them felt well but had both enlarged lymph nodes and laboratory evidence of severe immune system abnormalities, Johnson said.

Results Inconclusive

In the first group, none of 52 patients who received an 800-milligram dose of ribavirin developed AIDS, according to ICN officials.

In the second group, six of 55 patients who received a lower dose of the medicine went on to develop AIDS.

In the third group, 10 out of 56 patients who received placebo pills developed AIDS, said ICN officials.

Most patients taking the drug had no side effects, but some developed mild anemia, Johnson said.

Partial results of the just completed study were announced days after ICN provided detailed data on the trials to the U.S. Food and Drug Administration. The agency, which is expediting expected approval of another promising AIDS drug, azidothymidine, confirmed that it is reviewing ICN’s data but said it had no immediate plans to make the drug more widely available.

Reactions Mixed

Researchers participating in ICN-sponsored trials of ribavirin had mixed reactions when asked to comment on the significance of the announcement.

“I believe this represents some hope,” said Dr. Peter Heseltine of the County-USC Medical Center in Los Angeles. “I would like to see more data before I would be enthusiastic,” added Dr. Lawrance Kaplan of San Francisco General Hospital.

After the announcement, ICN Pharmaceuticals’ common stock fell $1.75 a share to $23.50 in heavy trading early this afternoon. And more than 2.2 million shares had been traded by midday, making ICN the New York Stock Exchange’s second most active issue. ICN’s Viratek Inc. subsidiary, which manufactures the drug, fell $1, to $75 a share, in noontime trading on NASDAQ. Volume was a heavy 407,700 shares.

The sell-off appeared to be the result of investor disappointment that data released today, while favorable, dealt only with a portion of the clinical trials, which have been under way since early 1986.

Times Staff Writer Robert Hanley in Orange County also contributed to this story.