Study shows CMV drug is ineffective and costly

Aug. 2, 2021

A commonly used treatment for pregnant women infected with a virus that can cause deafness and other harms to newborns provides no benefit, according to a large, multi-center study led by a researcher at Duke Health.

The study was designed to determine whether monthly infusions of hyperimmune globulin were effective in preventing the transmission of cytomegalovirus (CMV) infection from mothers to their developing fetuses. The study was stopped early as data showed the treatment was futile among women receiving the therapy.

Findings appear July 29 in the New England Journal of Medicine.

“This infection can have severe outcomes for babies — it’s the leading cause of deafness in newborns and it can cause other developmental issues, as well, said Brenna Hughes, MD, Associate Professor in Duke's Department of Obstetrics & Gynecology. “Women have often never heard of the virus, so it comes as a shock that there are these potential impacts during pregnancy, and no preventions or effective treatments.”

CMV is a common virus that infects people of all ages, typically causing mild or no symptoms. But when a woman who is pregnant becomes infected with it, the virus can pass through the placenta to the developing fetus — a capability that few other viruses possess.

Approximately 40% of CMV infections among pregnant women get passed along to the fetus; about 10% of infected fetuses have symptoms at birth, including deafness and cognitive and motor delays. Some children do not display symptoms until later in life.

Small, observational studies offered hope that CMV hyperimmune globulin might prevent fetal infections or lessen the virus’s impact. The therapy has been used in the U.S. under an Investigational New Drug approval from the U.S. Food and Drug Administration (FDA), which required the current study.

For their analysis, the researchers screened more than 206,000 pregnant women for primary CMV infection before 23 weeks of gestation from 2012 to 2018.

Of the 712 participants who tested positive, 399 were randomly assigned to receive either the therapy or a placebo. Neither patients nor their doctors knew who was receiving the active drug.

Among 203 women who received the therapy, 46 fetuses or babies were infected with CMV and/or suffered complications, including jaundice, hearing loss, low birth rate, seizures and other conditions. Nearly 5% of the babies in this study group died.

By comparison, 37 of 191 women in the placebo group had babies who were exposed to the virus, and only 2.6% of the newborns in the placebo group died. Preterm births occurred in 12.2% of the therapy group, and 8.3% in the placebo group.

“We had hoped the therapy would show benefit, because we so desperately need something to address CMV infections,” Hughes said. “But knowing that this therapy is not effective is helpful. It’s a very expensive treatment — it costs thousands of dollars per infusion — and it has been used fairly aggressively around the country. This study should save patients from receiving an unnecessary treatment.”

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