NCT06078696

Siplizumab for Sickle Cell Disease Transplant

Siplizumab-based Conditioning for Hematopoietic Stem Cell Transplantation in Patients With Advanced Sickle Cell Disease (CD2 SCD)

• Status: Terminated
• Phase: Phase 1 / Phase 2
• Study type: Interventional
• Enrollment: 1 (actual)
• Sponsor: Columbia University · Academic / Other
• Sex: All
• Age: 18 Years – 50 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this study is to find out whether siplizumab is safe and effective for patients with SCD undergoing an allogeneic transplant and to prevent development of Graft versus Host Disease (GVHD) and graft failure. The main goals of this study are : * To determine if acute GVHD occurs and how severe the acute GVHD is in subjects receiving the study drug * To determine if graft failure occurs in subjects receiving the study drugs In this study, participants will receive 5 infusions of the study drug, siplizumab, while getting a stem cell transplant for SCD. Before siplizumab infusion, participants will be given medications to reduce the risks of allergic reaction to the drug.

Detailed description

Phase I/II label single arm safety assessment study of Siplizumab-based conditioning. It is designed to determine the safety and feasibility of hematopoietic stem cell transplantation for patients with advanced sickle cell disease using in vivo T cell depletion with Siplizumab. It is a three-stage design with a target sample size of at most 18 patients. At the first stage, a total of 6 patients will be recruited, the study will be stopped, if 2 or more of patients experience any of the following events: graft failure/Grade 3-4 acute GVHD/death in the first 100 days. If not, the study will proceed to the second stage and recruit additional 6 patients. The study will be stopped if 4 or more patients experience an event as specified above among the 12 patients. If not, the study will proceed to the third stage and recruit additional 6 patients, the study will be stopped any time if 6 or more patients experience an event among the 18 patients. The study will be stopped at any time if a patient death occurs.

Conditions

• Anemia, Sickle Cell

Interventions

Type	Name	Description
DRUG	Siplizumab	Premedication with diphenhydramine 50 mg PO is to be given 1 hour prior to siplizumab infusion. Premedication with hydrocortisone succinate 100 mg IV infused over 30 minutes and acetaminophen 650 mg PO are to be given at least 30 minutes prior to siplizumab infusion. Siplizumab 4.8 mg/kg total is given on Day -14 and 0.6mg/kg is given on days -6, -1, 0, and +1. It will be given as an IV infusion over 1 hour.
PROCEDURE	Exchange Transfusion	Patient will undergo a red blood cell exchange transfusion to achieve a Hemoglobin S (HgbS) level \< 20% prior to starting therapy to prevent the development of a vaso-occlusive Crisis (VOC).
PROCEDURE	Total Body Irradiation	Radiation dose is 2Gy (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	Stem Cell Infusion	Standard institutional procedures should be followed for the processing and administration of stem cell products for infusion. The infused graft under no circumstances is to be irradiated. No in-line leukocyte filter should be used and no medications or fluids should be given piggyback through the catheter lumen used for infusion of stem cells. Vital signs should be monitored before beginning the infusion and periodically during administration and in accordance with institutional guidelines. Pre-medications prior to the graft infusion will be according to the institutions standard practice. Benadryl, epinephrine, hydrocortisone, and oxygen be available at the bedside, as well as an emergency medical code cart available in the vicinity of the patient, for emergency use in case of an infusion reaction.
DRUG	Cyclophosphamide 50mg	Cyclophosphamide will be given on days +3 and +4 at a dose of 50 mg/kg. Hydration prior to cyclophosphamide should be given according to standard institutional practice. Day +3 dose should occur between 60 and 72 hours after graft infusion and day +4 post-transplant should occur approximately 24 hours after prior dose. Cyclophosphamide will be given as an IV infusion over 1-2 hours depending on volume or as per institutional standard practice. Cyclophosphamide will be dosed according to adjusted ideal body weight (AIBW) in patients weighing \> 125% ideal body weight (IBW).
DRUG	Mesna	Mesna is to be given starting 1 hour prior to cyclophosphamide at the same dose (50 mg/kg) as a continuous infusion over 24 hours.
DRUG	Sirolimus Oral Tablet	Sirolimus will be given orally with a loading dose of 12 mg, then followed by 4 mg orally daily. Dosage will be adjusted to a therapeutic target of 10 - 15ng/ml in first 3 months post transplant and 3-10 after 3 months. Sirolimus should be started on day +5. It will be continued until at least day 180. Sirolimus can be tapered or continued according to the treating physician discretion and the presence of absence of GVHD and/or degree of donor chimerism. Sirolimus should be continued if donor chimerism is less than 50% to prevent graft loss.
DRUG	Rituximab or Biosimilar	Rituximab (375 mg/m2/dose) will be administered on Days -14 and -6. In those subjects receiving ongoing renal replacement therapy, rituximab should be administered several hours after hemodialysis. The first rituximab solution for infusion should be administered intravenously at an initial rate of 50 milligrams/hour (mg/hr). The rate may be escalated by 50mg/hr every 30 minutes to a maximum of 400 mg/hr. Subsequent infusions may be started at 100 milligrams/hour (mg/hr) and titrated by 100 mg/hr every 30 minutes to a maximum of 400mg/hr if the subject tolerated the first infusion.

Timeline

• Start date: 2023-09-28
• Primary completion: 2024-12-11
• Completion: 2025-12-11
• First posted: 2023-10-12
• Last updated: 2026-02-27
• Results posted: 2026-02-27

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study