A Long-Term Follow-Up Study of Participants With Sickle Cell Disease or Transfusion Dependent β-Thalassemia Who Received EDIT-301

The purpose of this study is to evaluate the long-term safety and efficacy of EDIT-301 in participants with severe sickle cell disease (SCD) or transfusion-dependent β-thalassemia (TDT) who have received EDIT-301.

Study Overview

• Status: Enrolling by invitation
• Conditions: Sickle Cell Disease; Hemoglobinopathies; Transfusion-dependent Beta-Thalassemia
• Intervention / Treatment: Other: Safety and efficacy assessments

Detailed Description

This is a non-interventional, multicenter study evaluating the long-term safety and efficacy of EDIT-301 in participants with severe sickle cell disease (SCD) or transfusion dependent b-thalassemia (TDT) who received EDIT-301 in parent studies EM-SCD-301-001 (NCT04853576) or EDIT-301-BThal-001 (NCT05444894). No investigational drug product will be administered in the LTFU study.

• Study Type: Observational
• Enrollment (Estimated): 54

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Ottawa, Ontario, Canada, K1H 8L6
      • Ottawa Hospital Research Institute
    • Toronto, Ontario, Canada, M5G 2M9
      • Princess Margaret Cancer Centre-University Health Network
• United States
  • California
    • Oakland, California, United States, 94609
      • UCSF Benioff Children's Hospital
  • Colorado
    • Aurora, Colorado, United States, 80045
      • Children's Hospital Colorado
  • Connecticut
    • New Haven, Connecticut, United States, 06511
      • Smilow Cancer Hospital
  • Florida
    • Saint Petersburg, Florida, United States, 33701
      • Johns Hopkins All Children's Hospital
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Children's Healthcare of Atlanta
  • Minnesota
    • Minneapolis, Minnesota, United States, 55410
      • University of Minnesota
  • New York
    • New York, New York, United States, 10032
      • Columbia University Medical Center
    • New York, New York, United States, 10032
      • Columbia University Medical Center - Department of Pediatrics
  • North Carolina
    • Charlotte, North Carolina, United States, 28204
      • Atrium Health
  • Ohio
    • Cleveland, Ohio, United States, 44195
      • Cleveland Clinic
    • Columbus, Ohio, United States, 43205
      • Nationwide Children's Hospital
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Children's Hospital of Philadelphia
  • South Carolina
    • Charleston, South Carolina, United States, 29425
      • Medical University of South Carolina
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Tristar Medical Group Children's Specialists/Sarah Cannon Center for Blood Cancers
  • Texas
    • Dallas, Texas, United States, 75246
      • Texas Oncology - Baylor Charles A. Sammons Cancer Center
    • Fort Worth, Texas, United States, 76104
      • Cook Children's

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population will be subjects currently enrolled in any one of the two parent studies ( EM-SCD-301-001 or EM-301-BThal-001)

Description

Inclusion Criteria:

• Participant must have received an EDIT-301 infusion as part of a clinical study.
• Participant or legal representative/guardian (if applicable) must sign and date the informed consent form (ICF) or assent, if applicable for this long-term follow-up study.

Exclusion Criteria:

• Participant is still actively enrolled in an EDIT-301 treatment study and has not yet met eligibility for long term follow-up in this study.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
All participants; All participants who complete or discontinue one of the parent studies (EM-SCD-301-001 or EDIT-301-BThal-001)	Other: Safety and efficacy assessments; Assessed throughout the duration of the study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Adverse events of special interest (AESI)	up to 15 years post EDIT-301 infusion
Adverse events of interest (AEI)	up to 15 years post EDIT-301 infusion
All-cause mortality	up to 15 years post EDIT-301 infusion
Adverse events (AEs) related to EDIT-301	up to 15 years post EDIT-301 infusion
Serious adverse events (SAEs)	up to 15 years post EDIT-301 infusion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of SCD participants with severe vaso-occlusive events (sVOEs) over time post-EDIT-301 infusion		up to 15 years post EDIT-301 infusion
Proportion of SCD participants with vaso-occlusive events (VOEs) over time post-EDIT-301 infusion		up to 15 years post EDIT-301 infusion
Frequency of SCD-related transfusions over time post-EDIT-301 infusion for SCD participants		up to 15 years post EDIT-301 infusion
Proportion of TDT participants with sustained transfusion independence (TI) over time		up to 15 years post EDIT-301 infusion
Proportion of TDT participants with sustained transfusion reduction (TR) over time		up to 15 years post EDIT-301 infusion
Frequency of TDT-related transfusions over time post-EDIT-301 infusion for TDT participants		up to 15 years post EDIT-301 infusion
SCD and TDT: Percent of peripheral red blood cells (RBCs) containing HbF (F-cells) over time		up to 15 years post EDIT-301 infusion
SCD and TDT: Total hemoglobin (Hb) concentration (g/dL) over time		up to 15 years post EDIT-301 infusion
SCD and TDT: Proportion of alleles with intended genetic modification present in peripheral blood nucleated cells and bone marrow derived CD34+ over time		up to 15 years post EDIT-301 infusion
Average HbF (pg) per RBC over time for SCD participants		up to 15 years post EDIT-301 infusion
Complete Blood Count (CBC) red cell indices assay over time for SCD participants		up to 15 years post EDIT-301 infusion
Average HbF (pg) per F-cell over time for SCD participants		up to 15 years post EDIT-301 infusion
HbF and HbS concentration (g/dL) over time for SCD participants		up to 15 years post EDIT-301 infusion
The level of HbF production determined by fractionation of different forms of Hb (including but not limited to HbA, HbA2, HbC, HbD, HbE, and HbS) over time for SCD participants.		up to 15 years post EDIT-301 infusion
Percentage of HbF over total non-transfused total Hb (non-transfused total Hb refers to the total g/dL of all Hb variants, excluding HbA) over time for TDT participants.		up to 15 years post EDIT-301 infusion
HbF concentration (g/dL) over time for TDT participants		up to 15 years post EDIT-301 infusion
Iron overload of TDT participants	As measured by a) Liver iron concentration (LIC) as assessed by R2* magnetic resonance imaging (MRI) for the first 3 years in this study; b) Cardiac iron concentration (CIC) as assessed by T2* MRI for the first 3 years of this study; c) Serum ferritin levels over time.	up to 15 years post EDIT-301 infusion
Proportion of TDT participants receiving iron chelation therapy over time.		up to 15 years post EDIT-301 infusion

Collaborators and Investigators

• Sponsor: Editas Medicine, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): June 17, 2024
• Primary Completion (Estimated): August 1, 2040
• Study Completion (Estimated): August 1, 2040

Study Registration Dates

• First Submitted: April 9, 2024
• First Submitted That Met QC Criteria: April 9, 2024
• First Posted (Actual): April 12, 2024

Study Record Updates

• Last Update Posted (Actual): April 2, 2025
• Last Update Submitted That Met QC Criteria: March 28, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: Anemia; Hematologic Diseases; Sickle Cell Disease; Genetic Diseases, Inborn; Sickle Cell Anemia; Beta-Thalassemia; Hemoglobinopathies; Thalassemia Intermedia; Sickling Disorder Due to Hemoglobin S; Autologous CD34+; Anemia, Hemolytic; Anemia, Hemolytic, Congenital; Thalassemia Major; CRISPR-Cas12a
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Hematologic Diseases; Anemia, Hemolytic, Congenital; Anemia, Hemolytic; Anemia; Anemia, Sickle Cell; Thalassemia; beta-Thalassemia; Hemoglobinopathies
• Other Study ID Numbers: EDIT-301-LTFU-001

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No