TreatmentUpdate82 - Vol. 9, No. 8 - pp. 1-2; October 1997
Sean Hosein

The anti-cancer drug Hydrea (hydroxyurea) has anti-HIV activity when used by itself in lab experiments. When used together with the antiviral ddI, it boosts levels of ddI inside cells, thereby increasing its anti-HIV effect. As a result, this combination is being tested in people at various stages of HIV infection. Most recently, in a study of 21 people pre-treated with or intolerant to AZT, a combination of ddI/Hydrea was able to reduce the level of HIV in the blood to 1/10th its pre-study value, but only for 12 to 16 weeks. Moreover, because of Hydrea's toxicity to the bone marrow and its resultant negative impact on blood cell production, dramatic increases in CD4+ cell counts were not commonly seen. Now reports from Germany and France suggest that in 3 people, Hydrea used with ddI appeared to suppress HIV long after treatment had been stopped.

Study details/Results

In the German report, a male patient had a viral load of 85,000 copies shortly after becoming infected with HIV. Doctors gave him a combination of indinavir, ddI and Hydrea. His viral load fell to levels where it could not be detected. After 4 weeks, he stopped treatment for 3 days and HIV could again be detected. He resumed his therapy and his viral load again fell below the level of detection. Five months after starting his therapy, the patient developed severe hepatitis A and had to stop taking his medication for 3 weeks. During that time, his viral load was again below the level of detection and has remained there for 9 months even though he has stopped taking his medication. Researchers think that this man is still infected, but that the virus is somehow trapped inside his cells.

Meanwhile, French researchers have reported data on 2 patients who had been infected with HIV roughly 3 and 12 months before starting treatment. Their CD4+ counts were within the normal range and their viral loads were at 676 and 1120 copies. Both were free of symptoms of HIV infection and each received ddI 400 mg/day and Hydrea 1,000 mg/day. They were treated for 1 year, after which doctors withdrew their medication for a year and continued to monitor them.

The amount of HIV in their blood fell below the level of detection and remained that way for the two years for which data were available. As well, viral load levels in lymph node samples were also undetectable. The lower limit of detection of the viral load test used by the researchers was 200 copies. Technicians searched inside cells found in the lymph nodes and detected small amounts of HIV's genetic material. Clearly the men remain infected.

Once again, these researchers are not sure why their patient's viral loads are so low. Perhaps this is an effect of treating people at a very early stage of HIV infection. However, long term observation is needed to see if the CD4+ counts, health and viral loads of these patients will remain stable.

REFERENCES:

1. Cohen J. HIV Suppressed long after treatment. Science 1997;26:5334:1927.

2. Vila J, Bugier F, Bargu G, et al. Absence of viral rebound after treatment of HIV-infected patients with didanosine and hydroxycarbamide. Lancet 1997;350:635-636.

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