Pegtibatinase as a Treatment for Patients with Classical Homocystinuria (HCU) (also known as the COMPOSE Study)

You likely can't join if

• Double-blind Treatment Period (Cohorts 1-6): 1. Previous exposure to pegtibatinase and/or previous participation in a clinical trial that included administration of pegtibatinase; 2. Use or planned use of any injectable drugs containing PEG (other than pegtibatinase or coronavirus disease 2019 [COVID-19] vaccines), including medroxyprogesterone (eg, Depo-Provera) injection, within 3 months prior to Screening and during study participation; 3. A prior reaction that included systemic symptoms (eg, abnormal respiratory or gastrointestinal signs or symptoms, fever, hypotension, angioedema, or anaphylaxis) to a PEG-containing product; 4. Known hypersensitivity to any components of pegtibatinase; 5. A history of organ transplantation or of chronic immunosuppressive therapy; 6. Concurrent disease or condition (eg, history or presence of clinically significant cardiovascular, pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, neurological, oncologic, or psychiatric disease) that would interfere with study participation or safety (excluding complications of HCU).
• OLE Period (Cohorts 1-6): 1. The participant developed an intolerance to the study drug.
• Pediatric Open -label Treatment Period (Cohort 7): 1. Diagnosis of Marfan syndrome, methylenetetrahydrofolate reductase (MTHFR) deficiency, or disorder of cobalamin metabolism, based on clinical, biochemical, and/or molecular genetic testing. 2. Concurrent disease or condition (eg, history or presence of clinically significant cardiovascular, pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, neurological, oncologic, or psychiatric disease) that would interfere with study participation or safety (excluding complications of HCU); 3. Body weight <15 kg; 4. Use or planned use of any injectable drugs containing PEG (other than pegtibatinase and PEG-containing vaccines), including medroxyprogesterone (eg, Depo-Provera) injection, within 3 months prior to Screening and during study participation; 5. Previous exposure to pegtibatinase and/or previous participation in a clinical trial that included administration of pegtibatinase or pegtarviliase. Participants may be consented to the ENSEMBLE study prior to COMPOSE study completion to ensure continuity of study drug between the 2 studies; 6. A prior severe immune reaction that included systemic symptoms (eg, abnormal respiratory or gastrointestinal signs or symptoms, fever, hypotension, angioedema, or anaphylaxis) to a PEG-containing product; 7. Known hypersensitivity to any components of pegtibatinase; 8. A history of organ transplantation or severe chronic immunosuppressive therapy during the last 6 months prior to Screening.