CMV Hyperimmune Globulin Does Not Cut Risk of Congenital Infection

A new study has found that cytomegalovirus (CMV) hyperimmune globulin (HIG) was not effective at decreasing risk of congenital CMV infection or fetal death in early pregnancy.

According to the US Centers for Disease Control and Prevention (CDC), infants born with signs of congenital CMV infections may develop long-term health problems including hearing loss, developmental and motor delay, vision loss, microcephaly, or seizures.

Currently, there is no universally accepted method of preventing congenital CMV. Therefore, a team of investigators set out to evaluate if administering CMV HIG to women with primary CMV infection during pregnancy could, in turn, reduce congenital infections.

The findings from the study were presented in a late breaking oral abstract session at IDWeek 2019.

The trial included women with a single gestation less than 24 weeks with primary CMV infection, as confirmed with IgM and IgG with low avidity or IgG seroconversion and assessed at a central reference laboratory. Patients with evidence of fetal CMV were ineligible.

From 2012 to 2018, 206,111 pregnant women were screened, for which 712 (0.35%) were found to have primary CMV infection. Across 17 centers, 399 women were enrolled into the randomized, double-masked trial.

Participants received monthly infusions of HIG (100 units/kilogram) or placebo until delivery. The mean gestational age at the point of randomization was 16.2 and 15.6 weeks in the HIG and placebo groups, respectively.

The primary outcome of the study was fetal loss or neonatal CMV infection, as confirmed by polymerase chain reaction or culture in urine or saliva within 3 weeks of birth, or in amniotic fluid prior to delivery. Data available for 394 participants indicate that the primary outcome rate was 22.7% in the HIG group and 19.4% in the placebo group (relative risk [RR], 1.17; 95% confidence interval [CI], 0.80 to 1.72; p=0.42).

Originally, a sample size of 800 participants was planned to “detect at least 30% reduction in the primary outcome with 90% power and type I error 5%.” However, the trial was halted at the recommendation of the Data and Safety Monitoring Committee following an interim analysis that revealed complete enrollment was unlikely to demonstrate a significant outcome.

According to the authors, there was no overall significant difference in the proportion of women with a side effect. But, participants who received HIG had higher rates of headache (P = 0.05) and chills (P = 0.03). Additionally, the rate of preterm birth was 12.2% (25 of 206) in the HIG group and 8.3% (16 out of 193) in the placebo group (RR, 1.47; CI 0.81 to 2.67; P= 0.2).

The abstract, Randomized Trial to Prevent Congenital Cytomegalovirus (CMV), was presented in a late breaker session at IDWeek 2019 on Saturday, October 5, 2019, in Washington DC.