Serious adverse events were reported

Sporadic laboratory abnormalities, in particular low SCH772984 levels and raised blood urea nitrogen levels, were observed occasionally for all of the vaccine groups, including placebo. The majority of the abnormalities were mild. One abnormality, elevated bilirubin level in a subject in the 200-μg C. difficile + Al(OH)3 group on Day 3 after Dose 1, was assessed as severe (Grade 3). The subject had a high bilirubin value at screening (1.3 mg/dL [normal range 0–1.1 mg/dL]), which had returned to normal at rescreening (0.8 mg/dL). Grade 3 bilirubin was present on Day 3 (1.8 mg/dL) and Grade 2 bilirubin was reported on Day 37 (1.5 mg/dL) and Day 187 (1.6 mg/dL). Further vaccination was discontinued for this subject.
One abnormality, elevated bilirubin level in the 50-μg C. difficile + Al(OH)3 dose group at Month 1 (2.0 mg/dL immediately prior to Dose 2), was assessed as Grade 4. The subject had normal bilirubin levels at screening (1.0 mg/dL) as well as all other visits leading up to the Month 1 visit. A Grade 2 bilirubin level (1.6 mg/dL) was reported on Day 37, which returned to normal at an unscheduled visit (0.7 mg/dL) 1 month later. The sponsor requested that further dosing be discontinued for this subject; however, telophase mistakenly received the third dose of vaccine. The subject had normal bilirubin levels at Month 6 (0.6 mg/dL) and at Day 187 (1.0 mg/dL). The subject had no reported adverse events after the third dose and no other blood chemistry abnormalities during the study.