Neurological Conditions More Likely Among Children Exposed to Efavirenz in Utero

Eric Daar, M.D., and Claudia S. Crowell, M.D., M.P.H., at IDWeek 2018
Sony Salzman

The advent of antiretroviral therapy (ART) has undoubtedly protected more than a million children from mother-to-child HIV transmission during pregnancy, but new data presented at IDWeek 2018 in San Francisco cast doubt on the safety for babies in utero of regimens containing efavirenz (Sustiva, Stocrin) and dolutegravir (Tivicay, DTG).

Specifically, efavirenz use was associated with a 60% increased risk of neurological conditions in children, according to data presented by Claudia S. Crowell, M.D., M.P.H., assistant professor of pediatrics at the University of Washington and Seattle Children's Hospital.

Researchers also found a link between a second drug, dolutegravir, and neurological conditions, although this was less conclusive.

The research presented in San Francisco may change attitudes toward efavirenz, which was previously considered safe based on studies with newborns. However, Crowell's study draws on a larger cohort of children from the ongoing SMARTT study who were evaluated for long-term neurological conditions.

She and her colleagues found that neurological conditions manifested later in life, which is perhaps why they had been previously missed. On average, children were two years old when neurological conditions were detected.

The study included 3,747 children born to HIV-positive mothers, a majority of whom had been exposed to ART before birth. Of these children, 237 were diagnosed with some sort of neurological condition, including microcephaly, seizures, and eye problems.

Nearly one out of every 10 babies born to mothers taking efavirenz later developed neurological birth defects, compared with one out of 16 babies born to mothers taking other ART regimens.

"Children who were born to women who receive efavirenz-containing antiretrovirals in pregnancy were 60% more likely to be diagnosed with a neurological condition than women who received an ART regimen that did not contain efavirenz," Crowell said. "This was after adjusting for other potential risk factors."

Although efavirenz is not recommended as a first-line treatment, current guidelines suggest that women who become pregnant while on efavirenz-containing regimens should continue to take that regimen if it's well tolerated, Crowell explained.

Crowell and her colleagues also found a link between dolutegravir and long-term neurological conditions among children. In that case, about one out of every 23 children developed a neurological condition, but the number of mothers who took dolutegravir was so small (only 94 total) that this data wasn't necessarily conclusive, Crowell said.

However, this research builds on a growing body of evidence that certain ARTs may increase the risk of birth defects. For example, a groundbreaking study from Botswana published earlier this year found more definitive evidence that dolutegravir increases the risk of neural tube birth defects.

This finding prompted the U.S. Food and Drug Administration and other government agencies to issue public health warnings.

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Guidelines already recommend against stavudine (d4T, Zerit), didanosine (ddI, Videx), treatment-dose ritonavir (Norvir), and elvitegravir/cobicistat in pregnant women. Guidelines also suggest that pregnant women should be treated with regimens that include atazanavir (Reyataz), darunavir (Prezista), or raltegravir (Isentress), but dissuade switching if an existing treatment is working well.

But as recent data sets off safety alarms for additional drugs -- including dolutegravir and efavirenz -- doctors are calling for more research into the appropriate use of ARTs during pregnancy.

Recent data has "re-ignited the interest in understanding what will happen to women and their babies," said Eric Daar, M.D., chief, Division of HIV Medicine at Harbor-UCLA Medical Center.

Unfortunately, Daar added, there's no safe way to test this risk in a well-controlled scientific experiment. Instead, the research is happening in the real world, among women and children who have already been exposed to ARTs that could potentially cause birth defects.

"We still haven't, as a whole, determined what the best ART regimen for use in pregnancy is, so we have to continue to study this," said Crowell.