A Study of TAK-755 (rADAMTS13) With Little to No Plasma Exchange (PEX) Treatment in Adults With Immune-mediated Thrombotic Thrombocytopenic Purpura (iTTP)

An AE is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (e.g., a clinically significant abnormal laboratory finding), symptom, or disease temporally associated with the use of a drug, whether or not it is considered related to the drug. SAE: Signs, symptoms or outcomes which results in death, requires inpatient hospitalization or prolongation of hospitalization, results in persistent or significant disability/incapacity, results in a congenital abnormality/birth defect, or is an important medical event. Adverse events of special interest include major thrombotic events and treatment-related bleeding events.

Clinical response is defined as normalization of platelets and no clinical evidence of new or progressive ischemic organ injury. Normalization of platelets: First occurrence of normal platelet count (greater than or equal to [>=]150,000/microliter [mcL]) that is followed by a confirmatory platelet count of >=150,000/mcL and a lactate dehydrogenase (LDH) <1.5×upper limit of normal (ULN) at 48±12 hours after the first occurrence.

Platelet response is defined as first occurrence of normal platelet count (>=150,000/mcL) that is followed by a confirmatory platelet count of >=150,000/mcL at 48±12 hours after the first occurrence.

The number of PEX administered considered Zero when no PEX is administered and considered Minimal when 1 to 3 PEX are administered.

The number of PEX administered considered Zero when no PEX is administered and considered Minimal when 1 to 3 PEX are administered.

Overall indicates clinical response regardless of whether on-study PEX is administered, or the number of PEX administered.

Overall indicates platelet response regardless of whether on-study PEX is administered, or the number of PEX administered.

Treatment failure is defined as failure to achieve clinical response, or experience iTTP recurrence.

Treatment failure is defined as failure to achieve platelet response, or experience iTTP recurrence.

iTTP recurrence comprised of exacerbation or relapse. Clinical exacerbation: Occurs <30 days after achieving initial clinical response (i.e., before clinical remission) and recurrent thrombocytopenia (platelet levels <150,000/μL), with or without clinical evidence of new or progressive ischemic organ damage, requiring daily PEX or rescue therapy. Clinical relapses: Occurs >=30 days after achieving initial clinical response (i.e., after clinical remission) and recurrent thrombocytopenia (platelet levels <150,000/μL), with or without clinical evidence of new or progressive ischemic organ damage, requiring daily PEX or rescue therapy.

iTTP recurrence comprised of exacerbation or relapse. Clinical exacerbation: Occurs <30 days after achieving initial platelet response (i.e., before clinical remission) and recurrent thrombocytopenia (platelet levels <150,000/μL), with or without clinical evidence of new or progressive ischemic organ damage, requiring daily PEX or rescue therapy. Clinical relapses: Occurs >=30 days after achieving initial platelet response (i.e., after clinical remission) and recurrent thrombocytopenia (platelet levels <150,000/μL), with or without clinical evidence of new or progressive ischemic organ damage, requiring daily PEX or rescue therapy.

Clinical remission is defined as achieving clinical response and no recurrence for >=30 days.

Clinical remission is defined as achieving platelet response and no recurrence for >=30 days.