Pregnancy, not nevirapine cause of liver toxicities in HIV-positive women

Results of US research “challenge the notion that nevirapine is uniquely associated with hepatotoxicity during pregnancy.” The study did however show that pregnancy itself increased the risk of liver toxicities in women with HIV. The research is published in the November 27^th edition of AIDS.

HIV treatment during pregnancy significantly reduces the risk of mother-to-child transmission of HIV. There is some evidence that treatment with nevirapine (Viramune) during pregnancy is associated with an incresaed risk of liver toxicity, especially if a woman has a CD4 cell count above 250 cells/mm³ when she starts therapy with the drug.

Investigators therefore performed a study to see if the association between nevirapine and liver toxicity differed according to pregnancy status.

HIV-positive women from two cohort studies (the Women and Infants Transmission Study and the International Maternal Pediatric Adolescent AIDS Clinical Trials protocol P1025) were included in the study, together with a comparison group of non-pregnant women with HIV from the Women’s Interagency HIV Study.

Two levels of liver toxicity were examined: any increases in liver enzymes above the limit of normal; and severe increases in liver enzymes above the upper limit of normal.

A total of 2050 women, 1229 (60%) of whom were pregnant, were included in the investigators’ analysis.

At baseline pregnant women were significantly younger, had higher baseline CD4 cell counts, lower viral loads, had a shorter duration of HIV infection, less hepatitis co-infection, and were more likely to be naïve to both antiretrovirals generally and nevirapine in particular than non-pregnant women.

Pregnant women (14%) were significantly more likely to develop elevations in their liver enzymes than non-pregnant women (9%, difference, p

However, the investigators failed to find any association between treatment with nevirapine and an increased risk of liver toxicity. A total of 13% of women taking this drug experienced increases in their liver enzymes above the upper range of normal compared to 10% of women not taking nevirapine. This was a non-significant difference.

Furthermore, comparable rates of nevirapine and non-nevirapine-treated women developed serious elevations in their liver enzymes (0.8% vs. 1%).

The investigators’ first set of statistical analysis showed that pregnancy, chronic hepatitis co-infection, viral load, and the presence of liver dysfunction at baseline were all associated with an increased risk of hepatotoxicity during follow-up.

No significant association was found between any elevations in liver enzymes, or severe elevations and treatment with nevirapine.

Pregnancy remained significantly associated with hepatotoxicity in multivariate analysis (p

Moreover, the investigators also performed a series of sensitivity analyses which also showed that pregnancy, but not nevirapine therapy, increased the risk of liver abnormalities.

“Our analysis suggests that a strong association between nevirapine and liver enzyme elevations was unlikely, regardless of pregnancy status and that pregnancy was a risk factor for liver enzyme elevations.”