HIV-2 case found, AIDS drug tested.

HIV-2 Case Found, AIDS Drug Tested

Recent reports of the first U.S. AIDS case caused by a second virus and results from human tests of a potential AIDS treatment illustrate how likely it is that 1988, like recent years, will be riddled with both optimism and pessimism in the now-global war against AIDS.

Physicians at the University of Medicine and Dentistry in Newark, N.J., said last week that they have diagnosed the first known U.S. case of AIDS caused by the virus called HIV-2. Although HIV-2 infection is frequently found in parts of West Africa, HIV-1 has been the cause of AIDS in the United States. Since HIV-2's discovery more than two years ago, scientists have debated whether this second virus actually causes full-blown cases of AIDS (SN: 3/7/87, p.151). Officials have been saying for months that it was inevitable that HIV-2 caused AIDS would be found in North America, with the virus already detected in Europe and Brazil.

Emphasizing that it is too early to assess the threat of HIV-2 in the United States, federal officials say there currently are no plans to specifically test the nation's blood supply for the virus. Peter J. Fischinger, AIDS coordinator for the U.S. Public Health Service, said last week at a Washington, D.C., briefing that existing HIV-1 screening tests cross-react with HIV-2 enough to handle the remote possibility of an HIV-2 blood donor. At the same briefing, Food and Drug Administration (FDA) Commissioner Frank E. Young said that prior screening of blood from more than 22,600 individuals in the United States had not detected infection with HIV-2. In anticipation of future HIV-2 spread, however, Young says the FDA is evaluating a rapid HIV-2 test in a "fast track" review process. He also says the FDA recommended last week that West Africans, like other high-risk groups, voluntarily exclude themselves from donating blood.

Young admits that potential treatments and tests for diseases other than AIDS have suffered under the FDA's concerted effort to rapidly review AIDS-related medical products. "We're running with bloody feet to try to keep up" with the many AIDS-related requests for FDA approval, he says.

Early last year, when zidovudine (AZT) became the first AIDS treatment approved by the FDA, human testing of other drugs was already underway. Among those candidate treatments was 2',3'-dideoxycytidine (ddC), a more potent relative of AZT that inhibits HIV-1 infection of cells (SN: 3/28/87,p.198). Last month, researchers published the results from the phase I clinical trials of ddC, which were designed to evaluate the drug's toxicity and potential curative effects.

The multicenter study-led by scientists at the National Cancer Institute in Bethesda, Md. - included 20 AIDS or AIDS-related complex (ARC) patients given ddC, plus another six patients given zidovudine alternating with ddC. Length of treatment depended on the individual's response to the drugs.

Whether given intravenously or orally, ddC effectively crossed the blood-brain barrier, which is important because the virus can infect brain cells and cause dementia. Both sets of patients also showed an increase in the total number of certain immune cells called T4 lymphocytes, which can be drastically reduced during HIV infection. But like zidovudine, which has adverse effects on the bone marrow, ddC given alone is not without its problems. In addition to the rashes, mouth sores and fever of some ddC-treated patients, several patients developed reversible neurological symptoms, ranging from dizziness to dementia, after about three months of treatment.

More encouraging, say the scientists, are results from the smaller group of patients given ddC and zidovudine. At the time of the report, five of the six were without neurological symptoms after seven months of treatment.

Reporting in the Jan. 16 LANCET, the researchers note that "it is too early to say whether such a (combination) regimen will be better than AZT alone." But they conclude that the different toxicity profiles of ddC and zidovudine suggest that alternating the two therapies might help reduce adverse effects in patients.