Switching to a once daily-regimen including ritonavir-boosted atazanavir appears helpful in some HIV-infected children, but has led to unexpected virological failure in others, according to French researchers.

Dr. Stephane Blanche of Hopital Necker Infantes Malades, Paris and colleagues note that this new protease inhibitor is now widely used in adults but experience in children is limited.

The researchers report in the September issue of The Pediatric Infectious Disease Journal on their study of a small group of older children and adolescents who had expressed a strong desire for once-daily treatment in order to improve compliance.

In all, 23 such patients were switched to a single daily dose of ritonavir-boosted atazanavir in combination with two other nucleoside or non-nucleoside analogs.

At the time of the switch, the previous treatment had been effective in 11 of the children, based on viral suppression to less than 50 copies/mL, and not effective in the remaining 12. None of the viral genotypes was resistant to atazanavir.

Tolerance was good in most patients but two chose to stop treatment because of icterus, and another two because of nausea and vomiting.

In six of the children in whom the previous treatment had been ineffective, plasma viral load fell below 50 copies per mL within 3 months of treatment. However, poor compliance and treatment failure persisted in the other six.

Seven of the children with good control before the switch continued to have undetectable viral load. However, two such children experienced virological failure at 1 month, and the other two did so at 3 and 12 months.

The researchers note that in two of these children, viral susceptibility to the other drugs in the regimen “was not optimal.”

Thus, they conclude, switching from an effective regimen to one with once-daily treatment with ritonavir-boosted atazanavir should be considered “only in cases of optimally active combinations of the other 2 molecules.”



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