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Completed

NCT Number: NCT00447980

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

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.

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Key information

Conditions

Retinitis Pigmentosa Congenital, Hereditary, and Neonatal Diseases and Abnormalities Eye Diseases Eye Diseases, Hereditary Genetic Diseases, Inborn Retinal Degeneration Retinal Diseases Retinal Dystrophies

Age range

18 year–64 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Retina-Vitreous Associates Medical Group, Beverly Hills, California, United States

Loading trial locations.

About this study

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).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

NT-501

Drug

Low Dose

Other names: CNTF implant

Primary outcomes

  1. 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.

Secondary outcomes

  1. Change in Mean Humphrey Visual Fields Sensitivity

    Time frame: Baseline compared to 6, 12, 18, 24 and 30 months

  2. 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

Sponsors and collaborators

Lead sponsor

Neurotech Pharmaceuticals

Industry

Registry information

Official study title

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

Important dates

Study start
2007
Primary completion
2010
Study completion
2010
First posted
Mar 15, 2007
Registry last updated
May 1, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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