 - Female patients must be non-pregnant for TTP Remission and vWD-2b Cohorts, a serum pregnancy test at screening and a urine pregnancy test at Day 1 pre-dose must be negative; for the Acute TTP Cohort, a serum pregnancy test at Day 1 pre-dose must be negative, and willing to use effective, redundant methods of contraception i.e., for both self and male partner throughout the study and for at least 30 days after participation. If possible, the treatment will be initiated within 5 days of the cessation of the preceding menstrual period; 