A study to find how well budoprutug (TNT119) works and how safe it is in participants with immune thrombocytopenia

Who can take part

• Aged > 18 years at the time of informed consent
• Mean platelet count of <30,000/μL (and individually ≤35,000/μL), despite at least one adequate therapeutic attempt, on at least 2 measurements at least 5 days apart, but no more than 14 days apart. Local laboratory values may be used for one of the values to determine eligibility if collected within 14 days prior to signing of Informed Consent Form (ICF) or if collected during screening
• Partial thromboplastin time < 1.5 × upper limit of normal (ULN), prothrombin time < 1.5 × ULN, total bilirubin < 1.5 × ULN unless due to Gilbert’s syndrome, or an international normalized ratio < 1.5 at screening
• Adequate hematologic, hepatic, and renal function
• If being treated with corticosteroids or thrombopoietin (TPO) agonists, subjects must be on a stable dose (< 20% change in dose over the 14 days prior to the first dose of study drug). Corticosteroid treatment should not be > 1 mg/kg methylprednisolone (or equivalent) for 2 weeks prior to the first dose of study drug
• Diagnosed with primary ITP

Who cannot take part

• Prior treatment with rituximab or other B-cell depleting agents within 24 weeks prior to the first dose of study drug or plan to receive B-cell depleting agents during the study
• Prior treatment with immunosuppressants (other than corticosteroids) within 30 days or 5 times the elimination half-life (whichever is longer) of the Screening Visit (e.g., calcineurin inhibitors, mycophenolate mofetil, azathioprine), or alkylating agents within 180 days of the Screening Visit
• Hospitalization within 14 days prior to Screening. Certain subjects may be included after consultation with the Medical Monitor
• Receipt of a live vaccine within 28 days prior to the first dose of study drug or during the study. All other vaccines must be completed within 21 days prior to the first dose of study drug
• Diagnosis of paroxysmal nocturnal hemoglobinuria, Evan’s Syndrome, or any other bleeding disorder that could confound results and impact subject safety
• Active, chronic, or latent /occult infection at the time of informed consent or study drug initiation
• Secondary cause of ITP (e.g., malignancy, hepatitis B or C, HIV, or other autoimmune diseases [e.g., thyroiditis], or drug-induced ITP)
• CD19+ B-cell count < 80 cells/μL at Screening or < 40 cells/μL if B-cell depleting treatment was received within 24 weeks to 2 years prior to Screening ((e.g., rituximab, or if the subject has received or is receiving other immunosuppressive or immunomodulatory agent with the potential to reduce circulating B-cell levels)
• Current or planned treatment with any chronic anticoagulants or platelet aggregation-inhibiting drugs such as aspirin, nonsteroidal anti-inflammatory drugs, or thienopyridines within 14 days of planned dosing through the end of follow-up. Symptom-based intermittent dosing of nonsteroidal anti-inflammatory drugs is permitted