Response to treatment after single dose NVP exposure in infants
Polly Clayden, HIV i-Base
A poster from Linda Barlow-Mosha and coworkers showed findings from an analysis of treatment response to a NVP-based regimen in HIV-positive Ugandan children, who were exposed or unexposed to single dose NVP at birth.
There were 92 children enrolled in this study and they received 3TC/d4T/NVP. The children who had been exposed to NVP cohort were significantly younger than the NVP-unexposed children: median age 1.7 years (range 0.6 to 6.3) vs 7.8 years (range 2.9 to 12.4) (p<0.001).
The investigators reported, both groups showed substantial increases in median CD4 percentage. Baseline 8.5%, 48 weeks 22.5% cells/mm3; Baseline 14.0%, 48 weeks 33.0% cells/mm3 in the unexposed and exposed children respectively (p<0.0001)
The childrens median baseline viral load was 650,568 copies/mL in the NVP exposed group and 239,027 copies/mL in the NVP unexposed group. Viral load response was similar in the two groups: 80% of the NVP unexposed and 76% of the single-dose NVP exposed group an undetectable viral load (<400copies/mL) at 48 weeks (p=0.74).
The investigators concluded that their data suggest that prior single dose NVP exposure did not have a negative effect on treatment success for children placed on a NVP-based HAART at a median age of 1.7 years.
Data describing infant repose to treatment following single dose nevirapine are even scarcer than those for mothers. These are encouraging. Findings from Lockman et al from the Mashi study were not: 10/15 exposed treatment infants having treatment failure at 12 months vs 1/15 unexposed. But these are tiny numbers. 
More studies are ongoing: the NEVEREST (Nevirapine Resistance Study) is evaluating response to treatment in women and children exposed to single-dose NVP; and IMPAACT 1060 is comparing the responses to initiation of NNRTI-based versus PI-based antiretroviral treatment in infants who have and have not previously received single dose NVP. Both are being conducted in South Africa.
This continues to be an areas in which we need more data.
- Barlow-Mosha L, Ajunua P, Mubiru M et al. Early effectiveness of a NVP-based HAART regimen among HIV-infected children with and without prior single-dose NVP exposure. 15th CROI. February 2008. Boston USA. Poster abstract 583.
- Lockman S, Shapiro RL, Smeaton LM, et al. Response to antiretroviral therapy after a single, peripartum dose of nevirapine. N Engl J Med 2007; 356: 135-147.