Sickling Disorder Due to Hemoglobin S

The purpose of this study is to find the smallest amount of the 131 I-apamistamab needed for preparing patients with severe sickle cell disease (SCD) for a bone marrow transplant. This is the first time 131 I-apamistamab is being used for advanced Sickle Cell Disease (SCD) in the setting of allogeneic stem cell transplant. 131 I-apamistamab is an investigational product. This means that 131 I-apamistamab has not been approved by the Food and Drug Administration (FDA) for medical use in patients. The study treatment that is given before the transplant is called the conditioning regimen. In this study, the investigators are adding a drug called 131 I-apamistamab instead of the conditioning regimen typically given before a stem cell transplant.

HSCT is currently the only curative option for SCD but less than 20% of SCD patients have a MD donor available. So far, all curative approaches beyond a MSD HSCT at young age are non-satisfactory. With the lack of a suitable donor for the vast majority of patients, the major question of this trial is, if a haploidentical αß/CD19+ T-cell depleted HSCT can be a valid alternative to a MSD HSCT. The main challenge in non-malignant diseases is to offer a safe and GvHD-free HSCT without rejection.