A Study to Evaluate CSJ148 in Pregnant Women With Primary HCMV Infection

Inclusion Criteria: 1. Written informed consent must be obtained before any assessment is performed. 2. Pregnant women ≥ 18 years of age with primary HCMV infection occurring between 6 and 24 weeks of gestation 3. Ability to receive study drug within 6 weeks of the presumed onset of primary maternal infection. 4. Able to communicate well with the investigator, to understand and comply with the requirements of the study. Exclusion Criteria: 1. Confirmed or suspected fetal HCMV infection, defined as positive HCMV DNA in amniotic fluid or fetal ultrasound abnormalities suggestive of fetal HCMV disease. 2. Prior treatment with any of the following within 30 days prior to enrollment: ganciclovir, valganciclovir, foscarnet, cidofovir, acyclovir (\>25 mg/kg/day IV), valacyclovir (\>3 gm/day oral), famciclovir (\>1500 mg/day oral), HCMV immune globulin, immune globulin (\>500 mg/kg), or any other medication with anti-HCMV activity. 3. Any surgical or medical condition (other than pregnancy) which might increase the risk for thrombotic events if the patient is given immune-globulins. These conditions include cryoglobulinemia, monoclonal gammopathies, and hypertriglyceridemia (fasting level \>1000 mg/dL). The investigator should make this determination based on the patient's medical history and laboratory data. 4. History of chronic hepatitis B, hepatitis C and human immunodeficiency virus (HIV) infection. Cured hepatitis C in not considered exclusionary. 5. Patient request for medical interruption or termination of pregnancy before inclusion. 6. Any surgical or medical condition which may jeopardize the patient or fetus in case of participation in the study. The investigator should make this determination in consideration of the patient's obstetrical history. 7. Use of other investigational drugs at the time of enrollment, or within 5 half-lives of enrollment, or until the expected pharmacodynamic effect has returned to baseline, whichever is longer; or longer if required by local regulations. 8. History of hypersensitivity to any of the study treatments or excipients or to drugs of similar chemical classes. 9. Body weight \> 100 kilograms.