Research
has shown that using nevirapine in this manner can lead to the development of
resistance mutations in women and their infants. But it remains unclear whether
this compromises the effectiveness of nevirapine - and other NNRTIs - if the women
or babies should later need to use the drug as part of combination antiretroviral
therapy.
In the
present study, reported in the January 11, 2007 New England Journal of Medicine,
researchers studied the response to nevirapine-based antiretroviral therapy among
women and infants who had previously been randomly assigned to receive a single
peripartum (during labor) dose of nevirapine or placebo in a perinatal HIV transmission
trial. All the women were treated with AZT
(Retrovir) during pregnancy. The primary end-point for mothers and infants
was virological failure by the 6-month visit after initiation of therapy.
Results
•
Of 218 women who started antiretroviral therapy, 112 had received single-dose
nevirapine and 106 had received placebo during labor.
•
By the 6-month visit after the initiation of combination therapy, 5.0% of the
women who had received placebo experienced virological failure, compared with
18.4% of those who had received single-dose nevirapine (P = 0.002).
•
Among 60 women who started
combination antiretroviral therapy within 6 months after receiving single-dose
nevirapine or placebo, no women in the placebo group and 41.7% in the nevirapine
group experienced virological failure (P <
0.001).
•
In contrast, virological
failure rates did not differ significantly between the placebo and single-dose
nevirapine group among the 158 women who started combination therapy 6 months
or more post-partum (7.8% vs 12.0%; P = 0.39).
•
30 infants started combination
antiretroviral treatment, 15 in the placebo group and 15 in the nevirapine group.
•
Virological failure by the
6-month visit occurred significantly more often in infants who had received single-dose
nevirapine than in those who had received placebo (P < 0.001).
•
Maternal and infant findings did not change by 12 and 24 months after the initiation
of antiretroviral treatment.
Conclusion
"Women
who received a single dose of nevirapine to prevent perinatal transmission of
HIV-1 had higher rates of virologic failure with subsequent nevirapine-based antiretroviral
therapy than did women without previous exposure to nevirapine," the investigators
concluded. "However, this applied only when nevirapine-based antiretroviral
therapy was initiated within 6 months after receipt of a single, peripartum dose
of nevirapine."
These
results suggest that single-dose nevirapine is a safe option for prevention of
mother-to-child transmission in women who are able to delay combination therapy
for their own treatment for at least 6 months.
"If you can wait six
months to administer nevirapine-based [antiretroviral therapy], do so," co-author
Max Essex, PhD, told Reuters Health. "If not, treat only with combinations
of drugs that do not contain nevirapine or nevirapine-related drugs. Implementing
this policy can improve the health of women who need AIDS treatment."
1/23/07
Reference S
Lockman, R L Shapiro, L M Smeaton, and others. Response to antiretroviral therapy
after a single, peripartum dose of nevirapine. New England Journal of Medicine
356(2): 135-147. January 11, 2007.
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