Long-term safety and antiretroviral activity of hydroxyurea and didanosine in HIV-infected patients

Long-term safety, immunologic effects, and antiretroviral activity of hydroxyurea and didanosine were evaluated in this retrospective study. Some 65 HIV-1-infected patients (39 of whom were antiretroviral naive) were studied (mean baseline CD4 count, 362 cells/mm(3); mean plasma HIV-1 RNA viral load, 4.8 log(10) copies/ mi). The mean treatment duration was 20 months. Overall tolerance was good: 15 patients interrupted treatment because of clinical or biologic side effects. Four patients experienced a category B event. Patients had a mean increase of 27 CD4 cell counts after 12 months, of 112 after 24 months and of 59 after 36 months. They had a mean 1.03 log(10) fall in HIV-1 RNA after 12 months, 1.59 log(10) after 24 months, and 1.27 log(10) after 36 months. After 12 months, 35% developed an HIV-1 RNA viral load <200 copies/ml, 53% after 24 months, and 36% after 36 months. Those whose viral load became undetectable after 12 months have significantly lower baseline RNA values (p =.03). Fourteen patients had a viral load <3.4 log(10) copies/ml after 24 months of the double therapy. A prolonged viral load suppression can be achieved using a simple combination of two drugs that are inexpensive and well tolerated.