Combination of Drugs Promising for Treatment of Toxoplasmosis

systems have been weakened by HIV infection or other causes, however, the parasite can reactivate
and cause damage to the central nervous system, leading to coma and death. The most common
symptoms of the infection are confusion, headaches, fever, paralysis, seizures and difficulty seeing,
speaking and walking. Once symptoms occur, treatment must be continued for life in order to
prevent recurrences.
In the study, Dr. Kovacs and his colleagues enrolled eight patients with toxoplasmosis who
could not tolerate the standard therapy. They gave two of the patients 1,200 milligrams of
azithromycin a day. After two weeks, X-rays showed that their toxoplasmosis was worsening, and
these patients were taken off the study and switched to another treatment.
Six other patients have been given a combination of 750 milligrams of 566C80, four times
a day, plus 50 milligrams of pyrimethamine, once a day. Three of the patients remain in the study
and their condition has improved or stabilized. One person appeared to be responding to the drug,
but died from other AIDS-related complications, and two others did not seem to benefit from the
drug.
Two patients on the 566C80/pyrimethamine regimen had a decline in the number of white
blood cells, but the treatment was otherwise well-tolerated.
In addition to Dr. Kovacs, the study investigators include Michael A. Polis, M.D., M.P.H.,
Barbara F. Baird, R.N., Irwin M. Feuerstein, M.D., Judith Falloon, M.D., Robert E. Walker, M.D.,
Richard T. Davey, M.D., H. Clifford Lane, M.D., and Henry Masur, M.D.
NIAID and the Clinical Center are components of the National Institutes of Health in
Bethesda, Md. NIAID supports research on allergy, immunology and infectious diseases, including
an extensive AIDS clinical research program at the Clinical Center, a 500-bed hospital on the NIH
campus.