IAS: Single dose nevirapine for mother doesn't lead to worse CD4 response to HAART

Women who took a single dose of the non-nucleoside analogue (NNRTI), nevirapine (Viramune) to prevent mother-to-baby transmission of HIV have an immunological response to HAART comparable to women who did not use nevirapine in this way, according to a study presented to the Third International AIDS Society Conference on HIV Pathogenesis and Treatment in Rio de Janeiro on July 25^th.

The study, the MTCT-Plus Initiative, was conducted in Abidjan, Cote d’Ivoire and provides HIV-positive women who are pregnant and who have given birth, their partners and children with HIV care and HAART when they meet World Health Authority eligibility criteria.

Although single dose nevirapine is highly effective at preventing mother-to-baby transmission of HIV, it is well established that the use of the drug in this way can lead to resistance to the drug in the mother. This is of particular concern as, in resource limited settings, HAART regimens based on nevirapine are recommended as first-line antiretroviral therapy by the World Health Organisation (WHO).

Given these concerns, investigators studied the immunological response of women treated with nevirapine-based HAART according to their use of single dose nevirapine to prevent vertical transmission of HIV.

Between August 2003 and February 2005 a total of 209 women were enrolled into the study. Of these women, 115 (55%) had previously received a single dose of nevirapine to prevent mother-to-baby HIV transmission. Of these women, 49 had taken nevirapine in combination with AZT (zidovudine, Retrovir) and 66 had taken nevirapine in combination with AZT and 3TC (lamivudine, Epivir).

The median delay between receiving therapy to prevent vertical transmission of HIV and starting HAART was 17 months, at which time the women had a median CD4 cell count of 191 cells/mm³.

All the women started a HAART regimen including nevirapine, with the overwhelming majority (93%) initiating treatment with a combination of nevirapine, AZT and 3TC. A small number of women (3%) took d4T in place of AZT and 3% took efavirenz instead of nevirapine.

For the 176 women for whom six month follow-up data were available, the median six month increase in CD4 cell count was 229 cells/mm³. There was no statistically significant difference between the 97 women who took a single dose of nevirapine to prevent vertical HIV transmission (median increase 217 cells/mm³) and the 79 women who did not use nevirapine in this way (median increase 242 cells/mm³, p = 0.30).

Twelve month data were available for 42 women. For the 15 women who had received single dose nevirapine, the median CD4 cell increase was 307 cells/mm³ and the median CD4 cell increase for the 27 women who did not take single dose nevirapine to prevent mother-to-baby transmission, the increase was 289 cells/mm³ (p = 0.37).

The only factors associated with clinical or immunologic failure in a multivariate analysis were age greater than 29 years and unemployment.

The investigators conclude, “the six-month immunological response was similar in women previously exposed or not to single dose nevirapine before initiating HAART.” However they caution, “further follow-up is necessary to fully assess the long-term impact of single dose nevirapine used for the prevention of mother-to-baby transmission of HIV on the success of NNRTI-containing therapeutic regimens.”