A Study of Elranatamab for Inhibitor Eradication in Patients With Hemophilia A

Inclusion criteria

• Male or female patients with moderate-to-severe hemophilia A (factor VIII activity <2%).
• Aged 18 to 65 years, inclusive.
• Positive factor VIII inhibitor detected on at least two consecutive occasions (inhibitor titer >0.6 BU/mL).
• Baseline factor VIII inhibitor titer >10 BU/mL at the time of enrollment.

Exclusion criteria

• Known hypersensitivity to Elranatamab or any of its excipients.
• Presence of other autoimmune diseases or a need for immunosuppressive therapy for reasons unrelated to this study.
• History of malignancy within 5 years prior to screening, with the exception of adequately treated carcinoma in situ of the cervix or non-metastatic cutaneous squamous cell carcinoma or basal cell carcinoma.
• History of severe recurrent or chronic infections, or acute infection requiring systemic treatment with antibiotics, antivirals, antiparasitics, antiprotozoals, or antifungal agents within 4 weeks before the first dose or during the screening period, or superficial skin infection requiring systemic therapy within 1 week before the first dose.
• Clinically significant laboratory abnormalities at screening, including:

• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >3 × the upper limit of normal (ULN).
• Total bilirubin >1.5 × ULN (subjects with documented Gilbert syndrome are not excluded based on this criterion);
• Absolute neutrophil count <1,500/mm³;
• Hemoglobin <9 g/dL or immunoglobulin G (IgG) <500 mg/dL;
• Absolute lymphocyte count <500/mm³;
• Creatinine clearance (CrCl) <30 mL/min.
• Positive test for HIV antibody or syphilis antibody.
• Positive hepatitis B surface antigen (HBsAg); or positive hepatitis B core antibody (anti-HBc) with detectable HBV DNA by polymerase chain reaction (PCR). Subjects positive for hepatitis C virus (HCV) antibody are excluded.
• Women who are pregnant or breastfeeding, or who plan to become pregnant or breastfeed during the study; men whose partners plan to become pregnant during the study.
• Subjects with psychiatric disorders that impair their ability to provide informed consent or comply with study procedures and follow-up.
• Subjects with unresolved toxicities from prior therapies before study participation.
• Any other condition that, in the opinion of the investigator, would make the subject unsuitable for participation in the study.