Wider Use of Experimental Drug to Fight AIDS Likely

Federal health officials are expected to announce soon that they will allow wider use of a new experimental AIDS antiviral drug for patients who cannot medically tolerate the two antiviral drugs already approved, knowledgeable sources said Tuesday.

The Food and Drug Administration will allow patients to use d4T, also known as stavudine, the source said.

The drug, manufactured by Bristol-Myers Squibb Co., will be available only to those who have not responded to treatment with AZT and a second antiviral drug, DDI, and who have no other options, sources said.

Eligible patients would include those who have experienced serious side effects from the drugs or whose conditions have worsened while taking them. This includes infected individuals with seriously deteriorated immune systems who have no symptoms and cannot take the drugs.

AZT, the most widely used AIDS drug, and DDI, also made by Bristol-Myers Squibb, have been approved as single-agent therapies. A third antiviral, DDC, which has proved ineffective alone, has been licensed only for use with AZT.

Antivirals are considered the major drugs to fight AIDS because they attack the underlying viral condition, unlike the drugs used to combat each individual opportunistic infection. Most researchers believe that the key to ultimately controlling AIDS lies in finding a successful combination of antiviral drugs.

Stavudine, whose wider use was described as “imminent,” will become available under the government’s “parallel track” program, meaning that it will be accessible while formal clinical studies are conducted to determine its effectiveness. The procedure is consistent with the government’s willingness in recent years to make unproven drugs more accessible to individuals with life-threatening diseases who have few or no therapy alternatives.

The new drug already has been studied in a small number of patients to determine whether it is safe. Larger trials to determine whether the drug is effective, by comparing d4T to AZT, are about to begin here and abroad.

All patients taking d4T under the “parallel track” program also will be included under a research umbrella--although in a more informal and less structured way. Data obtained from their experiences will be used to further evaluate the drug.

Like the other antiviral drugs, d4T works by inhibiting the infection of new immune system cells by the human immunodeficiency virus that causes AIDS.

Researchers do not yet know whether d4T can extend life or delay the onset of disease in those who are infected but not yet ill.

But like AZT and DDI, individuals who take d4T also seem to experience a sustained rise in their CD4 cells, the critical immune system cells that are the primary target of the AIDS virus.

“It’s been shown to decrease viral replication in patients, and we assume it will likely translate into immunological benefits and improvements in clinical status,” said Dr. Robert T. Schooley, an AIDS researcher.