Risk for resistant HIV increased with extended nevirapine prophylaxis

Infants who received six-week extended nevirapine prophylaxis to prevent HIV transmission had a higher frequency of resistant virus at 6 months of age, according to data presented at the 17th Conference on Retroviruses and Opportunistic Infections in San Francisco.

Researchers from the Six Week Extended Nevirapine (SWEN) Trial’s Ethiopian team analyzed data from infants who received single-dose nevirapine (NVP) only or single-dose NVP plus up to six weeks of daily NVP to prevent HIV transmission. Data indicated that there was a 46% reduction in risk of transmission in the six-week group compared with infants who received single-dose NVP only.

The researchers reported that 43 infants contracted HIV between birth and 14 weeks of age, and there was a 58% prevalence of NVP-resistance for those receiving extended NVP therapy, compared with 26% in the single-dose NVP-only group. They also noted a 40% resistance rate for both groups among infants who did not test positive for HIV until 6 months of age.

Timing of infection played a role in the prevalence of NVP-resistance, according to the researchers. Resistance prevalence for infants who contracted HIV by 1 week of age was 58% for the SWEN group compared with 38% in the single-dose group. For those infected between ages 1 and 6 weeks, prevalence was 57% and 17%, respectively, and 67% and 20% among those who contracted HIV between ages 6 and 14 weeks (after completion of intervention).

The researchers also said survival between age 6 months and 1 year was not different for infants with NVP-resistant and non-NVP-resistant infection.

“We conclude that nearly 60% of [infants with HIV] exposed to SWEN prophylaxis had high frequency NVP-resistance detectable at 6 months of age, and this finding is likely to result in decreasing response to early therapy with NVP-based regimens,” Deborah Persaud, MD, of the Johns Hopkins University School of Medicine, said during her presentation.

For more information:

Persaud D. Delayed clearance of high-frequency NVP-resistant viremia in the first year of life in HIV-infected infants who received extended NVP for prevention of breast-milk transmission: Implications for early therapy. #919. Presented at: 17th Conference on Retroviruses and Opportunistic Infections; Feb. 16-19, 2010; San Francisco.

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