Long-Term Follow-Up Gene Therapy Study for Achromatopsia CNGB3 and CNGA3

June 10, 2025 updated by: MeiraGTx UK II Ltd

Long-term Follow-up Study of Participants Following an Open Label, Multi-centre, Phase I/II Dose Escalation Trial of a Recombinant Adeno-associated Virus Vector (AAV2/8-hCARp.hCNGB3 and AAV2/8-hG1.7p.coCNGA3) for Gene Therapy of Adults and Children With Achromatopsia Owing to Defects in CNGB3 or CNGA3

This is a longer-term follow-up study of patients with achromatopsia associated with defects in CNGA3 who participated in a clinical trial in which they received AAV-CNGA3 retinal gene therapy, or of patients with achromatopsia associated with defects in CNGB3 who participated in a clinical trial in which they received AAV-CNGB3 retinal gene therapy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The follow-up study is designed to collect data on the longer-term safety and efficacy of AAV-CNGA3 retinal gene therapy and AAV-CNGB3 retinal gene therapy.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
34

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • London, United Kingdom
        • Moorfields Eye Hospital NHS Foundation Trust
  • United States
    • Michigan
      • Ann Arbor, Michigan, United States, 48105
        • Kellogg Eye Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

3 years to 100 years (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The study population are adults and children with achromatopsia resulting from mutations in CNGA3 or CNGB3.

Description

Inclusion in the study will be limited to individuals who:

  1. Are able to give informed consent or assent, with or without the guidance of their parent(s)/guardian(s), where appropriate
  2. Received AAV2/8-hCARp.hCNGB3 or AAV2/8-hG1.7p.coCNGA3 by intraocular administration in the prior open-label, Phase I/II, dose escalation study (EudraCT 2016-002290-35 or EudraCT 2018-003431-29)
  3. Are willing to adhere to the protocol and long-term follow-up

Individuals will be excluded who:

Are unwilling or unable to meet the requirements of the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Low dose of AAV-CNGA3 or AAV-CNGB3
Subretinal administration of a single low dose of AAV-CNGA3 or AAV-CNGB3
Biological: Prior exposure to AAV-CNGA3 or AAV-CNGB3
Participants previously received AAV-CNGA3 or AAV-CNGB3 in an open-label, Phase 1/2 dose escalation trial for adults and children with achromatopsia owing to defects in CNGA3 or CNGB3, respectively.
Intermediate dose of AAV-CNGA3 or AAV-CNGB3
Subretinal administration of a single intermediate dose of AAV-CNGA3 or AAV-CNGB3
Biological: Prior exposure to AAV-CNGA3 or AAV-CNGB3
Participants previously received AAV-CNGA3 or AAV-CNGB3 in an open-label, Phase 1/2 dose escalation trial for adults and children with achromatopsia owing to defects in CNGA3 or CNGB3, respectively.
Other dose of AAV-CNGA3 or AAV-CNGB3
Subretinal administration of a single other dose (between the intermediate and high dose) of AAV-CNGA3 or AAV-CNGB3
Biological: Prior exposure to AAV-CNGA3 or AAV-CNGB3
Participants previously received AAV-CNGA3 or AAV-CNGB3 in an open-label, Phase 1/2 dose escalation trial for adults and children with achromatopsia owing to defects in CNGA3 or CNGB3, respectively.
High dose of AAV-CNGA3 or AAV-CNGB3
Subretinal administration of a single high dose of AAV-CNGA3 or AAV-CNGB3
Biological: Prior exposure to AAV-CNGA3 or AAV-CNGB3
Participants previously received AAV-CNGA3 or AAV-CNGB3 in an open-label, Phase 1/2 dose escalation trial for adults and children with achromatopsia owing to defects in CNGA3 or CNGB3, respectively.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Incidence of Adverse Events Related to the Treatment
Time Frame: 5 Years
The primary outcome measure is the longer-term safety of treatment with AAV-CNGA3 or AAV-CNGB3, assessed by the absence of IMP-related adverse events.
5 Years

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Improvements in Visual Function as Assessed by Visual Acuity at Month 12
Time Frame: 12 months
Change from baseline to Month 12 in best corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study (ETDRS) chart letter score in the treated eye. The direction of improvement from baseline is an increase in the number of ETDRS letters read over time.
12 months
Improvements in Visual Function as Assessed by Visual Acuity at Month 60
Time Frame: 60 months
Change from baseline to Month 60 in best corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study (ETDRS) chart letter score in the treated eye. The direction of improvement from baseline is an increase in the number of ETDRS letters read over time.
60 months
Improvements in Retinal Function as Assessed by Static Perimetry at Month 12
Time Frame: 12 months
Change from baseline to Month 12 in contrast sensitivity in the treated eye. The direction of improvement is an increase in sensitivity.
12 months
Improvements in Retinal Function as Assessed by Static Perimetry at Month 60
Time Frame: 60 months
Change from baseline to Month 60 in contrast sensitivity in the treated eye. The direction of improvement is an increase in sensitivity.
60 months
Quality of Life at Month 12 Measured by QoL Questionnaires in Children and Adolescents
Time Frame: 12 months
Change from baseline to Month 12 in EuroQol-5D-Y Visual Analogue Scale (EQ-VAS) in children and adolescents. EQ-VAS uses a scale from 0 to 100, where 0 represents the worst imaginable health state and 100 represents the best imaginable health state. A positive change from baseline reflects improvement, and a negative change from baseline reflects worsening.
12 months
Quality of Life at Month 60 Measured by QoL Questionnaires in Children and Adolescents
Time Frame: 60 months
Change from baseline to Month 60 in EuroQol-5D-Y Visual Analogue Scale (EQ-VAS) in children and adolescents. EQ-VAS uses a scale from 0 to 100, where 0 represents the worst imaginable health state and 100 represents the best imaginable health state. A positive change from baseline reflects improvement, and a negative change from baseline reflects worsening.
60 months
Quality of Life at Month 12 Measured by QoL Questionnaires in Adults
Time Frame: 12 months
Change from baseline to Month 12 in EuroQol-5D-5L Visual Analogue Scale (EQ-VAS) in adults. EQ-VAS uses a scale from 0 to 100, where 0 represents the worst imaginable health state and 100 represents the best imaginable health state. A positive change from baseline reflects improvement, and a negative change from baseline reflects worsening.
12 months
Quality of Life at Month 60 Measured by QoL Questionnaires in Adults
Time Frame: 60 months
Change from baseline to Month 60 in EuroQol-5D-5L Visual Analogue Scale (EQ-VAS) in adults. EQ-VAS uses a scale from 0 to 100, where 0 represents the worst imaginable health state and 100 represents the best imaginable health state. A positive change from baseline reflects improvement, and a negative change from baseline reflects worsening.
60 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
MeiraGTx UK II Ltd

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Syne Qua Non Limited
EMAS Pharma

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 29, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 4, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 4, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 16, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 7, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 12, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 11, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 10, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • MGT007
  • 2016-003856-59 (EudraCT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Achromatopsia

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings