A Study of Encapsulated Cell Technology (ECT) Implant for Participants With Early Stage Retinitis Pigmentosa

April 14, 2025 updated by: Neurotech Pharmaceuticals

A Phase II/III Study of Encapsulated Human NTC-201 Cell Implants Releasing Ciliary Neurotrophic Factor (CNTF) for Participants With Retinitis Pigmentosa Using Visual Field Sensitivity as the Primary Outcome

The purpose of this study is to look at the safety and effectiveness of CNTF implants on vision in persons with retinitis pigmentosa, Usher type II & III, and Choroideremia. This research is being done because there are no effective therapies for people with these retinal degenerations. They are genetic disorders that affect one's ability to see at night, and later cause tunnel vision and loss of central vision. Retinal degenerations affect the retina, a light sensitive layer of cells in the back of the eye. Slowly over time, these cells die and cause permanent loss of vision.

The implant is a small capsule that contains human retinal pigment epithelium cells. These cells have been given the ability to make CNTF and release it through the capsule membrane into the surrounding fluid. In this study, two different CNTF dose levels will be used: a high dose and a low dose in one eye, as well as a sham (or placebo) surgery in the other eye.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This study will involve about 18 visits over 2½ years for specific tests of the participant's vision and health. These visits may include visual exams, blood draw for laboratory testing, brief medical history and exam, and occasionally a questionnaire (survey), in addition to the visit for the surgical procedures. The primary effectiveness outcome for this study will be a visual field score one year after the implant surgery. There will be about 12 centers participating in this study, and up to 60 people enrolled, across the US. Each participant joining the study who has completed initial screening will then be scheduled to have a brief surgical procedure performed on each eye, one of which will include a very small cell-filled implant. Follow-up visits for repeat assessments will be required regularly to determine if the implant being tested is safe and effective for use to treat retinitis pigmentosa (RP).

Study Type

Interventional

Enrollment (Actual)

73

Phase

  • Phase 2

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 States
    • California
      • Beverly Hills, California, United States, 90211
        • Retina-Vitreous Associates Medical Group
      • Sacramento, California, United States, 95817
        • University of Califoria, Davis
      • San Francisco, California, United States, 94143-0730
        • University of California, San Francisco
    • Florida
      • Miami, Florida, United States, 33101
        • Bascom Palmer Eye Insitute
    • Michigan
      • Ann Arbor, Michigan, United States, 48105
        • Kellogg Eye Center
    • Minnesota
      • Minneapolis, Minnesota, United States, 55455-0501
        • University of Minnesota
    • New York
      • New York, New York, United States, 10016
        • NY University Medical Center
    • Oregon
      • Portland, Oregon, United States, 97239-4197
        • Casey Eye Institue
    • Tennessee
      • Memphis, Tennessee, United States, 38163
        • The Hamilton Eye Institute
    • Texas
      • Dallas, Texas, United States, 75231
        • Retina Foundation of Southwest
    • Utah
      • Salt Lake City, Utah, United States, 84112
        • University of Utah
      • Salt Lake City, Utah, United States, 84132
        • The University of Utah - John A. Moran 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

Ages Eligible for Study

18 years to 64 years (Adult)

Accepts Healthy Volunteers

No

Description

Study inclusion / exclusion criteria:

Criteria for patients to qualify for the study include, but are not limited to:

  • Over 18 years of age, and less than 65 years of age
  • Diagnosis of retinitis pigmentosa, Usher Syndrome Type 2 or 3 or Choroideremia
  • Visual acuity no worse than 20/63
  • Experience with at least two full threshold Humphrey Visual Field 30-2 tests, one completed within the year prior to enrolling in this study

The following criteria will exclude patients from the study:

  • Pregnant or lactating females, or females planning to become pregnant during the study or not using an acceptable method of contraception.
  • Retinitis pigmentosa caused by a classic syndrome, including Usher Type I
  • Other eye diseases including advanced cataract.
  • Chronic systemic disease requiring continuous treatment with systemic steroids, immunosuppressive medications or insulin.

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Low Dose

NT-501 Low Dose Implant: encapsulated cell therapy that delivers ciliary neurotrophic factor to the retina

Sham Implant in Fellow Eye
Drug: NT-501
High Dose
Other Names:
  • CNTF implant
Drug: NT-501
Low Dose
Other Names:
  • CNTF implant
Experimental: High Dose

NT-501 High Dose Implant: encapsulated cell therapy that delivers ciliary neurotrophic factor to the retina

Sham Implant in Fellow Eye
Drug: NT-501
High Dose
Other Names:
  • CNTF implant
Drug: NT-501
Low Dose
Other Names:
  • CNTF implant

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Humphrey Visual Fields - Total Sensitivity
Time Frame: 12 months
The primary efficacy endpoint was the change in Humphrey VFS from baseline to month 12 (Visit 10) as determined by the HVF 30-2 test, comprised of 76 points. The measure was the sum of actual thresholds for all 76 locations.
12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Mean Humphrey Visual Fields Sensitivity
Time Frame: Baseline compared to 6, 12, 18, 24 and 30 months
Baseline compared to 6, 12, 18, 24 and 30 months
Mean Humphrey Visual Fields Sensitivity
Time Frame: Baseline compared to 6, 12, 18, 24 and 30 months
Change in Humphrey Visual Field Sensitivity over time
Baseline compared to 6, 12, 18, 24 and 30 months

Collaborators and Investigators

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

Sponsor

Neurotech Pharmaceuticals

Investigators

  • Principal Investigator: David Birch, MD, PhD, Retina Foundation of the Southwest

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

January 22, 2007

Primary Completion (Actual)

April 19, 2010

Study Completion (Actual)

April 19, 2010

Study Registration Dates

First Submitted

March 9, 2007

First Submitted That Met QC Criteria

March 14, 2007

First Posted (Estimated)

March 15, 2007

Study Record Updates

Last Update Posted (Actual)

May 1, 2025

Last Update Submitted That Met QC Criteria

April 14, 2025

Last Verified

April 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CNTF 4

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

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.

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