Congenital thrombotic thrombocytopenic purpura (cTTP) is a rare blood disorder that some people are born with. It is caused by a problem in a gene passed down from parents to children, which affects the body's ability to produce a enzyme called ADAMTS13. This enzyme helps to cut down a larger form of protein called von Willebrand Factor (VWF). People with cTTP have low levels of ADAMTS13. Without ADAMTS13, large forms of vWF build up and cause blood clots in small blood vessels. These clots can block blood flow to vital organs, causing serious health problems. Adzynma is a human ADAMTS13 protein made in the laboratory. It works the same way as natural ADAMTS13 does and may provide higher levels of ADAMTS13.

The main aim of this study is to learn more about the risk of children and adults with cTTP treated with Adzynma developing antibodies that prevent Adzynma from working properly (called neutralizing antibodies) within 6 months after the first treatment and to understand the risk of allergic reactions within 7 days of the first treatment with Adzynma. Other aims are to better understand how safe treatment with Adzynma is over a longer period of time (called long-term safety) in children and adults with cTTP and to gather information about pregnancies and babies of women who have received Adzynma while pregnant.

Only data already available in the medical records of the people who received Adzynma for the treatment of cTTP in normal clinical practice will be reviewed and collected during this study.

Inclusion criteria:

1. Is diagnosed with cTTP.
2. Had received commercially available Adzynma treatment for cTTP within the eligibility period of which there must be a recorded date and dose of at least one Adzynma administration in their medical chart.
3. Provides a signed informed consent form (informed consent form [ICF]; or assent and consent forms, if applicable), in accordance with local ethical and institutional requirements.

Exclusion criteria:

1. Has a history or presence of a functional ADAMTS13 inhibitor (that is, neutralizing antibodies to ADAMTS13/rADAMTS13).
2. Has concurrent use of an investigational drug or is enrolled in another clinical trial at the time of index Adzynma infusion.

Pediatric and adult participants who have received Adzynma for the treatment of cTTP, either prophylactically or as on-demand therapy for acute episodes-including those who became pregnant during Adzynma treatment.

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.