WASHINGTON -- A federal advisory panel recommended yesterday that the government approve the experimental antiviral AIDS drug DDC, but only to be used in combination with AZT, the most widely dispensed antiviral AIDS drug.
The committee, which advises the Food and Drug Administration, voted against recommending approval of DDC as a single-agent treatment, even for those who cannot medically tolerate AZT or the antiviral drug DDI. It said the research did not show the drug to be effective when used alone.
While recommendations made by advisory committees are not binding, the FDA almost always follows their advice.
The panel based its decision on studies showing that the combination regimen produced a dramatic and sustained increase in the number of CD4 cells, the critical immune system cells that are the primary target of the human immunodeficiency virus, compared to AZT alone.
HIV causes acquired immune deficiency syndrome.
Early evidence that a drug elevates CD4 cells is not necessarily an indication of how effective a drug will be. Nevertheless, the panel used the same criteria last summer to recommend approval of DDI, which was licensed last fall.
The FDA, which has been trying to move AIDS drugs to the market more quickly, has become increasingly willing to rely on such so-called "surrogate markers" to approve drugs.
At the same time, however, it has insisted on continuing controlled clinical studies after the drug is approved for use to determine whether it is indeed effective.
"We seem to be developing a partnership of concern -- that includes patients, scientists and federal officials -- that is now willing to take the risks necessary to address an epidemic that will not wait for a business-as-usual response," said Dr. Alvin Novick, a panel member.
The drug is manufactured by Hoffmann-La Roche Inc. of Nutley, N.J. The company has proposed approving the drug for adults with advanced HIV infection who have CD4 levels fewer than 300 per cubic milliliter of blood.
Normal counts range from 800 to 1,000.
If the agency approves DDC-AZT therapy for such individuals, those with AIDS infection who have not yet been treated with any antiviral drugs will face a tough decision: whether to take AZT alone -- which is now the standard of care -- or to start by taking both drugs together.