Drug That Prevents Mother-to-Infant HIV Transmission May Cause Developmental Effects

A drug commonly used to prevent HIV transmission during pregnancy may carry significant developmental effects on infants, according to a recent study.

Published in the journal AIDS, the study reported that the antiretroviral (ARV) drug atazanavir — a protease inhibitor – may slightly diminish language and social-emotional development scores compared with regimens that did not contain atazanavir.

Researchers from the Pediatric HIV/AIDS Cohort Study (PHACS) examined data from 917 infants who have HIV positive mothers, but who did not get the infection themselves. All of the infants’ mothers had been required to take ARV therapy in order to reduce the risk of HIV transmission.

Infants who were approximately 1-years-old were given 5 standard tests called the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley III) that would assess their developmental skill level.

Researchers took the scores and compared the 167 infants whose mothers took atazanavir versus 750 infants whose mothers did not.

The results of the study showed that mothers administered atazanavir had infants with lower language development scores. This was also true for infants with mothers that initiated atazanavir during the first trimester and during the second or third trimester of pregnancy.

Researchers also found that social-emotional development scores were lower for infants whose mothers took atazanavir. These differences were only significant when the mothers initiated ARV during the second of third semester only.

This is most likely due to women who began the regimen during their first trimester and then switched to a different ARV regimen later in their pregnancy.

In the tests for cognitive, motor, and adaptive behavior, there were similar results for infants exposed to atazanavir compared with unexposed infants. The average scores in all the subscales on the Bayley III test were within the normal range.

Although the differences in scores for language and social-emotional development were small, it was still significant. In fact, it was found that in the atazanavir group the language score was 3 points lower in comparison with the average subscale score of 93. The social-emotional score was 5 points lower compared with the average score of 100.

“(These differences) may not have large clinical implications, but they add another risk to the constellation of existing biological and socio-environmental risk factors to which these children are often exposed," said researcher Ellen C. Caniglia, ScD.