Clinical Trial

Disease: Sickle Cell Disease, SCD, and Transfusion Dependent Beta-Thalassaemia, TDT, (NCT04208529)

Disease info:

Sickle cell disease is a group of disorders that affects haemoglobin, the molecule in red blood cells that delivers oxygen to cells throughout the body. People with this disorder have atypical hemoglobin molecules called hemoglobin S, which can distort red blood cells into a sickle or crescent shape.

The production of hemoglobin A, which is the principle type of hemoglobin in humans, is governed by 3 genes: HBA1, HBA2, and HBB. Each hemoglobin A molecule consists of two alpha and two beta chains, and mutations in either of the HBA or the HBB genes may result in abnormal hemoglobin molecules with reduced or diminished function. Sickle cell disease arises from a single point mutation in the 6th codon  of the beta-globin gene (HBB), which results in a valine instead of a glutamic acid in the hemoglobin beta-chain.

Abnormal hemoglobin ultimately leads to anemia as well as other symptoms, depending on the exact mutations present. Diseases caused by defective hemoglobin fall into a larger category of diseases known as the "haemoglobinopathies" which also include the thalassemias, a related group of diseases that are characterized by reduced or deficient rather than abnormal haemoglobin. 

Sickle cell disease is the most common inherited blood disorder in the United States, affecting 70,000 to 80,000 Americans. The disease is estimated to occur in 1 in 500 African Americans and 1 in 1,000 to 1,400 Hispanic Americans.
Official title:
A Long-term Follow-up Study of Subjects With β-thalassemia or Sickle Cell Disease Treated With Autologous CRISPR-Cas9 Modified Hematopoietic Stem Cells (CTX001)

United States, New York

Columbia University Medical Center (21+ years)
New York, New York, United States, 10032

Columbia University Medical Center
New York, New York, United States, 10032

United States, Pennsylvania

Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States, 19104

United States, Tennessee

St. Jude Children's Research Hospital
Memphis, Tennessee, United States, 38105

The Children's Hospital at TriStar Centennial Medical Center/ Sarah Cannon Center for Blood Cancers
Nashville, Tennessee, United States, 37203

United States, Texas

Methodist Healthcare System of San Antonio, Methodist Hospital, Methodist Children's Hospital
San Antonio, Texas, United States, 78229


The Hospital for Sick Children
Toronto, Canada

Toronto General Hospital, University Health Network
Toronto, Canada

St. Paul's Hospital
Vancouver, Canada


Regensburg University Hospital, Clinic and Polyclinic for Paediatric and Adolescent Medicine
Regensburg, Germany

Universitätsklinikum Tübingen Klinik für Kinder- und Jugendmedizin
Tuebingen, Germany


Dipartimento di Onco-Ematologia e Terapia Cellulare e Genica Ospedale Pediatrico Bambino Gesu - IRCCS
Rome, Italy

United Kingdom

Imperial College Healthcare NHS Trust, Hammersmith Hospital
London, United Kingdom

Study start:
Jan. 20, 2021
Gene editing method:
Type of edit:
Gene disruption
BAF Chromatin Remodeling Complex Subunit 11A (BCL11A)
Delivery method:
Electroporation - Ex-vivo
IND Enabling Pre-clinical
Phase I Safety
Phase II Safety and Dosing
Phase III Safety and Efficacy

Status: Enrolling by invitation


This is a multi-site, observational study to evaluate the long-term safety and efficacy of CTX001 in subjects who received CTX001 in Study CTX001-111 (NCT03655678) or VX21-CTX001-141 (transfusion-dependent β-thalassemia [TDT] studies ) or Study CTX001-121 (NCT03745287) or VX21-CTX001-151 (severe sickle cell disease [SCD] studies; NCT05329649).

Last updated: Apr. 9, 2023
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