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AZT HELPS HEMOPHILIACS INFECTED WITH AIDS VIRUS
Clinical trials at 14 research centers, including Stanford University Medical Center, have shown that early treatment with zidovudine (AZT) delays the onset of AIDS in hemophiliacs older than 30 years of age who have no disease symptoms but are infected with HIV.
The study was a cooperative effort between the AIDS Clinical Trials Group (ACTG), funded by the National Institute of Allergy and Infectious Diseases (NIAID), and the National Hemophilia Foundation. The principal investigators were Dr. Thomas C. Merigan of Stanford University School of Medicine ACTG, and Dr. Jeanne Lusher of the National Hemophilia Foundation. A report of the findings appeared in August in the journal Blood.
"This study confirms the benefit of early treatment of HIV infection," said NIAID Director Dr. Anthony S. Fauci, "and demonstrates that giving AZT to persons with hemophilia does not appear to interfere with other treatments they may be taking."
"We were very encouraged by the fact that AZT's activity does not seem to be influenced by any liver function problems people with hemophilia may have," said Merigan.
People with hemophilia--caused by deficiency of a blood clotting factor--have a chronic need for transfusions of clotting factor concentrates. Of hemophiliacs who have become infected with HIV, most received tainted blood products before 1985, when screening for the AIDS virus began.
Because clotting factor concentrates are not screened for hepatitis C virus, 9 of 10 hemophiliacs become infected and may suffer hepatitis- induced liver disease. The liver is critical to the metabolism of zidovudine, so physicians were concerned that the drug might not be as effective in hemophiliacs as in other people infected by the AIDS virus.
The clinical trial, which began in 1988, compared the efficacy of zidovudine (AZT) versus placebo in people with hereditary bleeding disorders and concurrent asymptomatic HIV infection. For ethical reasons, the placebo arm of the study was stopped in August 1989 when interim analysis of data from another ACTG study showed that zidovudine clearly benefited certain asymptomatic HIV-infected people. As a result, no new patients were entered into the hemophilia study, and the 193 patients already enrolled were all given zidovudine.
The investigators continued to follow the patients' progress. The report just published, however, includes data gathered only up until the time the patients crossed over to the new zidovudine regimen. The average follow-up period was 9.6 months.
The study found that among hemophiliacs over 30 years old, those who received zidovudine fared better--fewer progressed to AIDS or died-- than those who received placebo. The study found no statistical difference between the placebo and treated groups in those younger than 30. The authors say this may be attributable to the fact that the study was stopped prematurely; therefore, there were fewer patients in this group and shorter follow-up than originally planned.
No special problems related to liver dysfunction could be attributed to the drug despite the high incidence of underlying liver disease in these patients. Side effects in some patients included anemia and another blood cell disorder, called granulocytopenia. Other subjective symptoms reported by those treated with zidovudine included nausea and weakness.
The investigators hailed the clinical trial as much for its success in recruiting patients as for its scientific results. Unlike some populations at risk for HIV infection, hemophiliacs are not concentrated in big cities near ACTG centers but rather are dispersed uniformly throughout the United States. Ten regional hemophilia centers worked with the National Hemophilia Foundation, outlying hemophilia centers, and the ACTG to enroll patients in the study.
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