NCT07015684

131I-apamistamab-based Conditioning for Hematopoietic Stem Cell Transplant (HSCT) in Advanced Sickle Cell Disease (SCD)

Open-label, Single-Center, Phase 1 Study to Estimate the Minimum Effective Dose (MED) of 131I-apamistamab for Non-myeloablative Conditioning in Patients With Severe Sickle Cell Disease

• Status: Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 24 (estimated)
• Sponsor: Columbia University · Academic / Other
• Sex: All
• Age: 12 Years – 50 Years
• Healthy volunteers: Not accepted

Summary

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.

Detailed description

The purpose of this study is to research the minimum effective dose (MED) of 131 I-apamistamab conditioning for hematopoietic stem cell transplantation for patients with advanced SCD. 131 Iapamistamab 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, investigators are adding 131 I-apamistamab instead of the conditioning regimen typically given before a stem cell transplant. The current standard of care conditioning for allogeneic stem cell transplant in SCD is a combination of chemotherapy, total body irradiation and an antibody called Campath. This study is being done to see if the stem cell transplant for SCD can still be effective by eliminating total body irradiation from the conditioning as it has potential long term side effects such as secondary cancers, infertility, early cataracts and lung toxicity. This is a single center, Phase I, dose finding study to estimate the MED of hematopoietic stem cell transplantation for patients with advanced sickle cell disease using 131I-apamistmab-based nonmyeloablative conditioning. The study will enroll 24 patients who are 12-50 years of age with sickle cell anemia (Hb SS, SC, or Sβ0 thalassemia) and have an available HLA-matched sibling donor.

Conditions

• Sickling Disorder Due to Hemoglobin S

Interventions

Type	Name	Description
DRUG	131I-apamistmab	131I-apamistamab is a drug construct consisting of the apamistamab monoclonal antibody (mAb) and radioactive isotope iodine 131 (131I). The study drug will be patient-specific and will be manufactured for dosing on a specific date. The antibody dose will be at least 0.5mg/kg, however the final antibody amount may be higher if necessary based on the target radioactivity level. The 131I-apamistamab study drug requires patient details such as height, weight, a calculation to determine weight for use in calculating antibody amount for the dose. 131I-apamistmab will be given via intravenous (IV) infusion.
DRUG	Sirolimus	Sirolimus is a macrocyclic lactone produced by Streptomyces hygroscopicus. It is an immunosuppressant agent. Sirolimus is to be given orally either as tablet or solution form. Dosage will be adjusted to a therapeutic target of 10-15 ng/mL in first 6 months post-transplant and 5-10 ng/mL after 6 months.
DRUG	Campath	Campath is a recombinant DNA-derived humanized monoclonal antibody that is directed against the 21-28 kD cell surface glycoprotein, CD52. CD52 is expressed on the surface of normal and malignant B and T lymphocytes, NK cells, monocytes, macrophages, and tissues of the male reproductive system. Campath will be given via IV at a total dose of 1 mg per kilogram of body weight.
DRUG	Total Body Irradiation	Radiation dose is 3Gy (Gy is a radiation unit of measurement). Radiation source and dose rates will be according to institutional practice. Total Body Irradiation (TBI) may be delivered from either linear accelerator or Cobalt sources.
PROCEDURE	Exchange Transfusion	Patient will undergo a red blood cell (RBC) exchange transfusion to achieve a Hemoglobin S (HgbS) level \< 20% prior to starting therapy to prevent the development of a vaso-occlusive Crisis (VOC).
RADIATION	Planar gamma imaging	Dosimetric imaging will be performed using quantitative planar gamma camera acquisition. Planar gamma imaging is a technique used in medical imaging to take pictures of the inside of the body, particularly to look at how certain organs or tissues are functioning. This allows the study doctor to evaluate how the study drugs are absorbed into the body.

Timeline

• Start date: 2025-04-28
• Primary completion: 2030-03-12
• Completion: 2032-03-12
• First posted: 2025-06-11
• Last updated: 2025-06-11

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study