DURBAN, South Africa - When given to both mother and child around the time of birth, nevirapine (Viramune, Roxane) greatly reduces mother-to-infant transmission of HIV up to a year, according to research presented at the 13th International AIDS Conference.
The latest findings stem from the continued follow-up of breast-feeding mothers and their babies enrolled in the HIVNET 012 clinical trial. Earlier results from the trial suggested that a short regimen of nevirapine given to both mother and child significantly reduced HIV transmission. The latest data indicate this reduction in HIV vertical transmission was sustained even though the infants were breast-fed.
The study, conducted at a teaching hospital of Makerere University in Kampala, Uganda, compared the safety and efficacy of a short course of nevirapine with a similar course of zidovudine (AZT, Retrovir, Glaxo Wellcome).
One group of women received a single dose of nevirapine during labor and their infants received one dose within 72 hours of birth. The second group of women received AZT during labor while their newborns received twice daily doses for seven days. After six to eight weeks, both regimens were well tolerated.
New data on those same infants 12 months later show nevirapine continued to reduce risk of HIV transmission even though the women breast-fed their infants. After six to eight weeks, nevirapine showed a 42% reduction in HIV transmission compared with AZT. At 12 months, the reduction was 39%, and preliminary results indicate a reduction of 42% after 18 months.
Genetic analysis of HIV in the mothers showed that while a small number of mutations do occur in the virus, those mutations fade from detection within 13-18 months after delivery. This suggests that repeat doses of nevirapine given to the mother will continue to prevent HIV transmission during future pregnancies.
Researchers also assessed how well the amount of HIV and CD4 T cells in the mother's blood would predict the likelihood of her passing the virus on to her baby. Women with more virus and fewer CD4 T cells in their blood were more likely to transmit HIV to their offspring than were those with less virus and more CD4 cells.
Together, these findings further indicate that a short nevirapine regimen is an effective, simple, and cost-effective method for preventing HIV vertical transmission in developing countries.
The trial was led by Brooks Jackson, MD, at The Johns Hopkins University and Francis Mmiro, professor at Makerere University. Statistical analysis was coordinated by Tom Fleming, MD, at the Fred Hutchinson Cancer Research Center in Seattle.
In a similar study also presented at the international AIDS meeting, nevirapine was compared with two antiviral drugs. Nevirapine was again shown to prevent HIV spread from mothers to infants during labor and delivery.
A recent study evaluated a short course of nevirapine vs. a seven-day course of a combination of AZT and lamivudine (3TC, Epivir, Glaxo Wellcome) for the prevention of vertical transmission. The randomized, open-label comparative trial enrolled more than 1,300 women who tested HIV positive in labor or late in pregnancy (>38 weeks) and had not previously received and were not currently receiving other antiretroviral therapy for HIV-1 infection.
In the nevirapine arm, one dose of nevirapine (200 mg) was administered to mothers with HIV while in labor followed by a second dose (200 mg) 24 to 48 hours after delivery. One dose (6 mg) was also given to infants 24 to 48 hours after birth.
Women in the AZT-3TC arm were initially given 600 mg of AZT, then 300 mg every three hours during labor and 300 mg twice daily for seven days plus 3TC (150 mg) twice daily during labor and 150 mg twice daily for seven days. Infants in this treatment arm received AZT (12 mg) plus 3TC (6 mg) twice daily for seven days after birth.
The overall rates of mother-to-child HIV transmission were 14% and 10.8% for the nevirapine and AZT-3TC arms respectively. The rates of vertical transmission that occurred in the intrapartum or early postpartum periods were 6.3% and 4.3% for the nevirapine and AZT-3TC arms respectively. Therefore, the differences were not statistically significant.
A safety analysis, which evaluated the same patient population, found no treatment-related serious adverse events through six weeks in either treatment group, however, the safety profile of nevirapine in neonates has not been established.
In related news, Roxane recently announced that nevirapine will be offered free to developing countries for five years to help prevent mother-to-child transmission of HIV.
For more information:
- Jackson B. Nevirapine and vertical transmission. Late breaker session. Presented at the 13th International AIDS Conference. July 9-14, 2000. Durban, South Africa.
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