P22.01
Background: Nevirapine-based antiretroviral therapy (NVP-ART) is commonly used in resource-limited settings for treatment of NVP unexposed HIV-infected infants. However, the frequency of resistance and impact of the resistance on viral suppression in this group of infants initiating early ART, have not been well-characterized.
Methods: To address this, we determined serial prevalence of NVP resistance during 12 months of ART among NVP-unexposed HIV-infected infants, enrolled in a clinical trial and initiated on NVP-ART, and determined effect of NVP resistance on viral levels.
Results: Of 99 infants screened, 42 had no reported NVP exposure, and 22 infants with no baseline NVP resistance were initiated on NVP-ART. During follow-up, 7 infants (32%) developed resistance, 1 infant at 3 months, and 6 at 6 months after ART initiation. HIV-1 RNA levels were similar at baseline among infants who developed resistance and those who did not (P=0.3). There was a trend for reduced viral suppression at 3 months of ART in infants with resistance than in those without (P=0.14) and after 6 and 12 months of ART, viral levels were significantly higher in infants with resistance than those without (P=0.007, P=0.014, respectively).
Conclusions: Among infants without previous exposure to NVP development of NVP resistance was frequent, and presence of resistant mutations in these infants was significantly associated with less viral suppression during the first year of ART. High prevalence of NVP-resistance during ART despite lack of NVP exposure may be due to higher baseline viral levels and longer viremia in infants following ART in contrast to adults. Development of NVP resistance may, in part, explain superiority of Protease inhibitor-based ART in infants.
