Inclusion Criteria:

        Participants with a clinical diagnosis of iTTP (initial or recurrent), which includes
        thrombocytopenia, microangiopathic hemolytic anemia (eg, presence of schistocytes in
        peripheral blood smear) and relatively preserved renal function. The iTTP diagnosis should
        be confirmed by ADAMTS13 testing within 48 hours (2 days).
        Participants with a clinical diagnosis of iTTP and a French TMA score of 1 or 2.
        A female participant is eligible to participate if she is not pregnant or breastfeeding,
        and one of the following conditions applies:
          -  Is a woman of nonchildbearing potential (WONCBP), OR
          -  Is a woman of childbearing potential (WOCBP) and agrees to use an acceptable
             contraceptive method during the overall treatment period and for at least 2 months
             after the last study drug administration.
        Male participants with female partners of childbearing potential must agree to follow the
        contraceptive guidance as per protocol during the overall treatment period and for at least
        2 months after last study drug administration.
        Exclusion Criteria:
        Platelet count ≥100 x 10^9/L. Serum creatinine level >2.26 mg/dL (200 µmol/L) in case
        platelet count is >30 x 10^9/L (to exclude possible cases of atypical HUS).
        Known other causes of thrombocytopenia including but not limited to:
          -  Clinical evidence of enteric infection with E. coli 0157 or related organism.
          -  Atypical HUS.
          -  Hematopoietic stem cell, bone marrow or solid organ transplantation-associated
             thrombotic microangiopathy.
          -  Known or suspected sepsis.
          -  Diagnosis of disseminated intravascular coagulation. Congenital TTP (known at the time
             of study entry). Clinically significant active bleeding or known co-morbidities
             associated with high risk of bleeding (excluding thrombocytopenia).
        Inherited or acquired coagulation disorders. Malignant arterial hypertension. Participants
        requiring or expected to require invasive procedures immediately (eg, stroke requiring
        thrombolytic therapy, those who need mechanical ventilation, etc.).
        Those presenting with severe neurological or cardiac disease. Clinical condition other than
        that associated with TTP, with life expectancy <6 months, such as end-stage malignancy.
        Known chronic treatment with anticoagulants and anti-platelet drugs that cannot be stopped
        (interrupted) safely, including but not limited to:
          -  vitamin K antagonists.
          -  direct-acting oral anticoagulants.
          -  heparin or low molecular weight heparin (LMWH).
          -  non-steroidal anti-inflammatory molecules other than acetyl salicylic acid.
             Participants who were previously enrolled in this clinical study (study EFC16521).
        Participants who received an investigational drug, or device, other than caplacizumab,
        within 30 days of anticipated IMP administration or 5 half-lives of the previous
        investigational drug, whichever is longer.
        Positive result on COVID test.
        The above information is not intended to contain all considerations relevant to a potential
        participation in a clinical trial.