Serial Monitoring and Hyperimmunoglobulin versus Standard of Care to Prevent Congenital Cytomegalovirus Infection: A...

Nonrandomized studies support the potential of cytomegalovirus hyperimmunoglobulin (CMV-HyperIg) in preventing maternofetal CMV transmission, but prospective interventional studies show equivocal results. We pre-sent a prospective phase-III international randomized open-label trial on the potential effect of CMV-HyperIg following serial monitoring of CMV serostatus.

CMV-seronegative pregnant women (gestational age [GA] <14 weeks) were 1:1 randomized to monthly CMV-serostatus monitoring and CMV-HyperIg upon seroconversion (treatment), or routine prenatal care with CMV-serostatus testing at end of pregnancy (control). Ethical considerations required that control subjects with confirmed seroconversion be offered Cytotect®. The primary endpoint was the proportion of fetuses/newborns with congenital CMV infection. Secondary endpoints included neonatal CMV disease and safety during the 24-month follow-up.

The treatment arm counted 4,800 randomized subjects: 52 seroconverted (median GA 24 [11-35] weeks), of which 45 completed follow-up. The control arm counted 4,735 randomized subjects: 42 seroconverted, of which 34 completed follow-up (evaluable data for 28 newborns) and 8 subjects chose off-label Cytotect®. Congenital CMV rates were 13/28 newborns (46.4% [CI 27.51; 66.13]) vs. 16/45 newborns (35.6% [CI 21.87; 51.22]) in control and treated arms, respectively (p = 0.46). Newborn CMV disease was mostly mild and spontaneously resolving. There were no major safety concerns. The target sample was not reached within an acceptable time frame.

Serial monitoring of CMV serostatus with CMV-HyperIg treatment was associated with a mild nonsignificant reduction in the vertical CMV transmission rate. Studies on the optimal preventive strategy are hampered by epidemiological and ethical challenges and should focus on GA-dependent transmission rates and accurate dating of infection.