Emma Hitt, PhD

July 21, 2011

July 21, 2011 (Rome, Italy) — Extended prophylaxis of infants born to mothers with HIV-1 infection with nevirapine or nevirapine and zidovudine significantly reduces postnatal HIV-1 infection when measured at 28 weeks, new research suggests.

Charles Van der Horst, MD, professor and associate director, Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, presented the research here at the 6th International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention, during a late-breaking session.

Dr. Charles Van der Horst

"There is currently a debate as to what to do for breastfeeding women with high CD4 counts (>350 cells/μL) who do not need treatment for their own health (ie, it is unclear whether to treat the mothers and hopefully prevent transmission to the breastfeeding infants, or give the infants prophylaxis)," Dr. Van der Horst told Medscape Medical News.

"There is a lot of pressure to treat all of the mothers, regardless of CD4 count, to prevent transmission, as it simplifies things somewhat, but this is very expensive and requires toxicity monitoring," he said. "By contrast, infant prophylaxis is very cheap, nontoxic, potentially carries less stigma than treating the adults, and is highly effective," he pointed out. According to Dr. Van der Horst, the large randomized PROMISE trial, sponsored by the National Institutes of Health, will hopefully answer this question definitively.

In the current analysis, data were pooled from 5 randomized trials including 5396 mother–infant pairs in which the infant was HIV-negative at birth, so that the researchers could estimate the efficacy of infant nevirapine prophylaxis to prevent breast-milk HIV-1 transmission. The 4 regimens evaluated were nevirapine for 6 weeks, 14 weeks, or 28 weeks, or nevirapine plus zidovudine for 14 weeks.

For the 6-week regimen, the estimated risk for postnatal transmission was 1.6% compared with 3.4% for control patients. For the 14-week regimens, the estimated risks were 1.9% with nevirapine only and 2.3% for nevirapine plus zidovudine compared with 7.3% for control patients.

At 28 weeks, the estimated risk for HIV-1 transmission was 5.8% (95% confidence interval [CI], 4.0% - 7.6%) for the 6-week nevirapine regimen, 3.7% (95% CI, 2.3% - 5.1%) for the 14-week nevirapine regimen, 4.8% (95% CI, 3.2% - 6.4%) for the 14-week nevirapine/zidovudine regimen, and 1.8% (95% CI, 0.8% - 2.8%) for the 28-week nevirapine regimen (log rank test for trend P < .001).

Statistical analysis revealed that nevirapine reduced the rate of HIV infection by 71% (95% CI, 58% - 80%; P < .001) and reduced the rate of HIV infection or death by 58% (95% CI, 45% - 69%; P < .001).

"It appeared that the longer the prophylaxis, the greater the benefit, which suggests that if you continued it for an entire year, it too would be beneficial," Dr. Van der Horst said. He added that this data set is particularly robust for a meta-analysis because individual patient data from similar groups of patients are being used.

The study was not commercially supported. Study drugs used were donated by each drug company. For the BAN Study (included in the pooled analysis), GlaxoSmithKline and Abbott supported some additional laboratory studies that are not part of this data set. Dr. Van der Horst has disclosed no relevant financial relationships.

6th International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention: Abstract WELBC03. Presented July 20, 2011.


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