Addition of zidovudine prophylaxis to nevirapine may reduce
nevirapine-resistance in postnatal infection
Supplementing extended nevirapine prophylaxis with
zidovudine significantly reduced the risk of nevirapine resistance at 14 weeks
in infants who contracted HIV in utero, provided that the prophylaxis was
stopped by 6 weeks of age, according to results from the Post-Exposure
Prophylaxis of Infants-Malawi trial.
“Extended infant nevirapine prophylaxis reduces
the risk of postnatal HIV transmission. However, it may induce resistance in
infants who are HIV-infected despite prophylaxis,” Jessica
Lidstrom, of the Johns Hopkins University School of Medicine, said during a
presentation of the data at the
17th
Conference on Retroviruses and Opportunistic Infections in San Francisco.
Lidstrom and colleagues evaluated levels of
nevirapine-resistance in 88 infants infected with HIV despite treatment with
extended nevirapine prophylaxis. At birth, the infants were randomly assigned
to one of three regimens. The control group received single-dose nevirapine
plus one week of daily zidovudine, the extended nevirapine group received the
control regimen plus daily nevirapine for 14 weeks and the extended nevirapine
plus zidovudine group received control plus daily nevirapine and zidovudine for
14 weeks. The researchers then analyzed plasma samples from the infants taken
at 14 weeks for nevirapine-resistance.
“Overall, our findings showed that the addition of
[zidovudine] to [nevirapine] reduced the risk of [nevirapine]-resistance in
infants, with 65.6% of infants having [nevirapine]-resistance in the dual
regimen arm while 86% of the infants had resistance in the [nevirapine]-only
arm,” Lidstrom said.
The researchers also investigated the effect that the
number of weeks that an infant received prophylaxis had on
nevirapine-resistance. Although they found that supplementing extended
nevirapine with zidovudine reduced nevirapine-resistance in infants infected at
birth, longer periods of prophylaxis did not affect nevirapine-resistance.
For more information:
Lidstrom J. Comparison of NVP resistance among HIV-infected
infants who received extended NVP plus ZDV prophylaxis vs. extended NVP
prophylaxis alone: The PEPI-Malawi Study. Presented at: The 17th Conference on
Retroviruses and Opportunistic Infections; Feb. 16-20, 2010; San Francisco.