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Extended NVP for Breastfed Infants Best With High Maternal CD4s

Author: Mark Mascolini

19 March 2011

When extended for 6 weeks after birth, nevirapine (NVP) prophylaxis for breastfeeding infants of HIV-positive mothers lowered HIV acquisition and promoted survival through 12 months better than single-dose nevirapine (sdNVP) when mothers had a CD4 count above 350 cells/µL, according to results of the SVEN trial.

SVEN trial investigators in Ethiopia, India, and Uganda reported earlier that nevirapine prophylaxis extended for 6 weeks in breastfeeding infants of HIV-positive mothers did not prevent HIV transmission better than sdNVP when infants were 6 months old (Six Week Extended-Dose Nevirapine (SWEN) Study Team, Bedri A, et al. Lancet. 2008; 372: 300-313). The new analysis reported 12-month results in 987 infants who received sdNVP and 903 infants who received extended nevirapine prophylaxis.

At 12 months overall HIV transmission rates were 8.9% in the extended-nevirapine group and 10.4% in the sdNVP group, not a significant difference. However, cumulative mortality at 12 months in the extended-nevirapine group was half that in the sdNVP group (risk ratio [RR] 0.53, 95% confidence interval [CI] 0.32 to 0.85).

Among infants of mothers with a CD4 count above 350 cells/µL, children receiving extended nevirapine had more than a 60% lower risk of death (RR 0.38, 95% CI 0.17 to 0.84) and almost a 50% lower risk of HIV transmission and death (RR 0.54, 95% CI 0.35 to 0.85) than children who received only sdNVP.

But extended nevirapine did not offer significant protection against HIV transmission and mortality in infants of mothers with a CD4 count of 200 cells/µL or lower or a count between 200 and 350 cells/µL.

“For populations with limited access to HAART,” the researchers conclude, “our results provide evidence for the use of extended-dose regimens to prevent infant deaths and increase HIV-free survival in infants of HIV-infected breastfeeding women, particularly for infants of women with CD4 cell counts more than 350 cells/μl.”

A recently reported double-blind trial involved 1522 HIV-negative breastfeeding African infants born to HIV-positive mothers who took extended nevirapine for 6 weeks (Nielsen-Saines K, et al. Phase III randomized trial of the safety and efficacy of 3 neonatal ARV regimens for prevention of intrapartum HIV-1 transmission: NICHD HPTN 040/PACTG 1043. 18th Conference on Retroviruses and Opportunistic Infections. February 27-March 2, 2011. Boston. Abstract 124LB). At that point infants were randomized to continue nevirapine for 6 months or to placebo. HIV rates among infants of mothers who had not started ART for their own health were 1.4% in the extended-nevirapine group and 3.4% in the placebo group (P = 0.027). Infection rates did not differ significantly between study arms in infants whose mothers began antiretroviral therapy for their own health.

Source: Saad B. Omer, for the Six Week Extended Dose Nevirapine (SWEN) Study Team. Twelve-month follow-up of six week extended dose nevirapine randomized controlled trials: differential impact of extended-dose nevirapine on mother-to-child transmission and infant death by maternal CD4 cell count. AIDS. 2011; 25: 767-776.

For the SVEN trial abstract

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