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VANCOUVER -- A small study suggests that a suspension formulation of the integrase inhibitor raltegravir (Isentress) may help prevent transmission of HIV from infected women to their newborns, researchers reported here.
In the retrospective study conducted in Canada, no mother-to-child transmission of HIV was observed among 18 babies exposed to the drug during utero, said Fatima Kakkar, MD, assistant professor of pediatrics at the University of Montreal.
At the biennial International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention, Kakkar also said that there were no significant congenital abnormalities associated with children whose mothers were given raltegravir.
In addition, newborns of two women infected with HIV who refused treatment during pregnancy who were treated with raltegravir after their birth were also HIV negative, she said. Raltegravir was used for neonatal prophylaxis as part of a triple-drug regimen in these newborns at high risk of HIV infection in the cohort through the Merck Special Access, Health Canada Compassionate use protocol.
"I think that raltegravir is a drug that has great promise for newborns," Kakkar told MedPage Today. "The drug toxicity is minimal and for the prevention of mother-to-child transmission the movement is to treat early. So by giving this drug early, even if the child turns out to be infected, the child is already on an effective treatment regimen."
Both of the women who refused antiretroviral therapy in pregnancy were themselves perinatally infected. "It is very typical among our kids who were infected perinatally and have grown up to refuse treatment," Kakkar said. "These patients are exceptionally difficult. They have had 20 years of antiretrovirals. Sometimes we can convince them, but other times we cannot. They have difficulty with adherence and they often have multidrug resistant virus. This is very similar in the United States as well as Canada."
In the study of the 18 women on raltegravir, 5 were taking the drug prior to pregnancy and 13 were on raltegravir during pregnancy. The 13 women treated with raltegravir during pregnancy were placed on the drug because of resistance to other medication had developed, or because high viral loads were observed during the third trimester of pregnancy or the women were late to start antiretroviral therapy.
At delivery, the maternal viral load was undetectable in 14 women, and was detectable at low levels in 3 women and at a high level in the 4th woman.
Compared to other antiretroviral drugs given to pregnant women, treatment with raltegravir resulted in similar outcomes as children treated with lopinavir/ritonavir (Kaletra) and with atazanavir (Reyataz) as far as gestational age, APGAR score, birthweight, birth length, and head circumference were concerned, Kakkar said in her oral presentation. Biochemistry laboratory outcomes were also similar for the newborns, except for a significant increase in bilirubin among the atazanavir treated patients – a known complication for that agent.
After 6 months, the growth parameters – weight, length, and head circumference – were almost exactly the same for the children regardless of the antiretroviral.
Co-moderator of the oral session, Sharon Walmsley, MD, professor of medicine at the University of Toronto, told MedPage Today that there are 2 aspects to this issue. "More women are going to be on antiretrovirals when they get pregnant since we will be starting treatment earlier, so we need to make sure this drug is safe in pregnancy. The second issue it that we do have women with multidrug resistant virus and sometimes we will need that drug. So we need a drug that is also able to protect the baby. But the number of babies treated in this study is small, so it is difficult to say too much about it."
Kakkar said that while Canadian health services have tried to eliminate mother-to-child HIV transmission, it still occurs. In women with at least 4 weeks of combination antiretroviral therapy, the incidence of transmission is less than 0.1%. However, if the mother has detectable viral load at delivery, the incidence of mother-to-child transmission rises to 3.1%; the risk increases to 4.3% if the mother received less than 4 weeks of antiretroviral therapy and reaches 15% if the woman is untreated.
"New strategies are needed for the management of these high-risk situations," Kakkar said, and hence the researchers are looking at raltegravir, although its use in pregnancy lacks data to determine its usefulness or toxicity to the infants. Under select circumstances, raltegravir has been used in late pregnancy in women with high viral loads to rapidly decrease viral load prior to delivery.
The patients in the retrospective study were taken from the Centre Maternel et Infantil sur le SIDA mother-child cohort, at CHU Sainte-Justine, Montréal, Quebec. All the infants were born to women during 2010 to 2015.
Kakkar disclosed no relevant relationships with industry.
Walmsley disclosed relevant relationships with AbbVie Inc., Gilead Sciences, Inc., Janssen Pharmaceuticals, Merck & Co., Inc., and ViiV Healthcare.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
International AIDS SocietySource Reference: Trahan M-J, et al "Raltegravir for the prevention of mother-to-child transmission of HIV" IAS 2015.