Adding Tenofovir (Viread) plus Emtricitabine (Emtriva) to Short-course Zidovudine (Retrovir) and Single-dose Nevirapine (Viramune) Does Not Reduce the Risk of Mother-to-child HIV Transmission

By Liz Highleyman

Retrovir Tablet

Viramune Tablet

Viread Tablet

Emtriva Capsule

A short course of zidovudine (AZT; Retrovir) and single-dose nevirapine (Viramune) at the time of delivery have been shown to reduce the risk of mother-to-child HIV transmission, but some babies still become infected.

As described in the June 1, 2008 Journal of Acquired Immune Deficiency Syndromes, researchers conducted a study to determine whether adding a single dose of peripartum tenofovir (Viread) plus emtricitabine (Emtriva) - the 2 drugs in the Truvada combination pill - would reduce the likelihood of HIV transmission during or shortly after delivery.

In this study, 397 HIV positive pregnant women receiving routine prophylactic short-course zidovudine and peripartum nevirapine were randomly assigned to either add a single dose of tenofovir (300 mg) plus emtricitabine (200 mg) during labor, or to receive no additional intervention. Infant outcomes were determined at 6 weeks.

Results

• Of 397 women randomized, 355 (89%) gave birth to infants who were alive and active at 6 weeks postpartum.

• Of these, 18 (5.1%) infants were infected with HIV in utero and 6 (1.8%) were infected during birth or the early postpartum period.

• Among the 243 women who used zidovudine and nevirapine, the rate of intrapartum or early postpartum HIV transmission was not reduced by the addition of tenofovir/emtricitabine.

• 2 of 123 infants (1.6%) were infected in the tenofovir/emtricitabine arm compared with 3 of 109 infants (2.8%) in the standard prophylaxis arm (P = 0.67; not a statistically significant difference).

• Among the 49 infants whose mothers did not receive prenatal zidovudine but who had confirmed ingestion of nevirapine, transmission rates also did not differ with addition of tenofovir/emtricitabine (0 of 19 [0%] vs 1 of 26 [3.4%], respectively).

• Tenofovir/emtricitabine was not significantly associated with reduced overall mother-to-child HIV transmission (OR 0.7), even when other antiretroviral drugs were considered (adjusted OR = 0.8).

"Adjuvant peripartum single-dose tenofovir/emtricitabine did not reduce perinatal transmission," the study investigators concluded. "Whether a higher dose might be effective remains unknown but should be studied in settings in which nevirapine is used without antenatal zidovudine."

Other studies have suggested that adding tenofovir/emtricitabine may reduce the risk of drug resistance among mothers who receive single-dose nevirapine without zidovudine, even if it does not lower the rate of HIV transmission.

Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; Schools of Medicine and Public Health, University of Alabama, Birmingham, AL; University Teaching Hospital, Lusaka, Zambia; Catholic Medical Missions Board, Lusaka, Zambia; University of Cape Town, Cape Town, South Africa.

6/20/08

Reference
BH Chi, N Chintu, RA Cantrell, and others. Addition of Single-Dose Tenofovir and Emtricitabine to Intrapartum Nevirapine to Reduce Perinatal HIV Transmission. Journal of Acquired Immune Deficiency Syndromes 48(2): 220-223. June 1, 2008.