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Retinitis PigmentosaPhase 2NCT00447980

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

A Phase 2 study testing NT-501 in people with Retinitis Pigmentosa, run by Neurotech Pharmaceuticals at 12 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

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. Read more about this study

Who is it for?
Ages 18 to 64 years
Conditions the study is for
Retinitis Pigmentosa
What is being tested?
NT-501
Could I receive a placebo?
No, everyone receives an active treatment
How many people
73 participants
Where
12 sitesUnited States
Study dates
22 Jan 2007to 19 Apr 2010
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 64 years
  • All sexes
  • No healthy volunteers
  • Adult

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.

Trial locations and contacts

12 sites in 1 country.

12 sites in 1 country

United States12 sites

  • Kellogg Eye Center

    Ann Arbor, Michigan, 48105

  • Retina-Vitreous Associates Medical Group

    Beverly Hills, California, 90211

  • Retina Foundation of Southwest

    Dallas, Texas, 75231

  • The Hamilton Eye Institute

    Memphis, Tennessee, 38163

  • Bascom Palmer Eye Insitute

    Miami, Florida, 33101

  • University of Minnesota

    Minneapolis, Minnesota, 55455-0501

  • NY University Medical Center

    New York, New York, 10016

  • Casey Eye Institue

    Portland, Oregon, 97239-4197

  • University of Califoria, Davis

    Sacramento, California, 95817

  • University of Utah

    Salt Lake City, Utah, 84112

  • The University of Utah - John A. Moran Eye Center

    Salt Lake City, Utah, 84132

  • University of California, San Francisco

    San Francisco, California, 94143-0730

Other trials in United States

About this study

Official 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

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.

Read the 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).

Being tested
NT-501
Keywords
Retinitis Pigmentosa, eye disease, retinal disorder, CNTF
Medical subject headings
Retinitis Pigmentosa, Eye Diseases, Retinal Diseases

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • NT-501Drug

    Also called CNTF implant

    Low Dose

  • NT-501Drug

    Also called CNTF implant

    High Dose

Study groups in NCT00447980
Study groupRoleWhat they receive
Low DoseExperimentalNT-501 Low Dose Implant: encapsulated cell therapy that delivers ciliary neurotrophic factor to the retina Sham Implant in Fellow Eye
Receives: Drug: NT-501
High DoseExperimentalNT-501 High Dose Implant: encapsulated cell therapy that delivers ciliary neurotrophic factor to the retina Sham Implant in Fellow Eye
Receives: Drug: NT-501

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Humphrey Visual Fields - Total Sensitivity

    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.

    Measured: 12 months

Secondary outcomes (2)

  1. Change in Mean Humphrey Visual Fields Sensitivity

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

  2. Mean Humphrey Visual Fields Sensitivity

    Change in Humphrey Visual Field Sensitivity over time

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

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted15 Mar 2007 (estimated)
  2. Study start22 Jan 2007
  3. Primary completion19 Apr 2010
  4. Study completion19 Apr 2010

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Double blind
Who is masked
Participant, Outcomes assessor
Enrolment
73 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT00447980
Sponsor's protocol ID
CNTF 4
Status last verified
Apr 2025
First submitted
9 Mar 2007
Last updated
1 May 2025
Data monitoring committee
Yes
Individual data sharing
No

Publications

  • Birch DG, Weleber RG, Duncan JL, Jaffe GJ, Tao W; Ciliary Neurotrophic Factor Retinitis Pigmentosa Study Groups. Randomized trial of ciliary neurotrophic factor delivered by encapsulated cell intraocular implants for retinitis pigmentosa. Am J Ophthalmol. 2013 Aug;156(2):283-292.e1. doi: 10.1016/j.ajo.2013.03.021. Epub 2013 May 10.

    PubMed 23668681

  • Kauper K, McGovern C, Sherman S, Heatherton P, Rapoza R, Stabila P, Dean B, Lee A, Borges S, Bouchard B, Tao W. Two-year intraocular delivery of ciliary neurotrophic factor by encapsulated cell technology implants in patients with chronic retinal degenerative diseases. Invest Ophthalmol Vis Sci. 2012 Nov 1;53(12):7484-91. doi: 10.1167/iovs.12-9970.

    PubMed 23049090

  • Talcott KE, Ratnam K, Sundquist SM, Lucero AS, Lujan BJ, Tao W, Porco TC, Roorda A, Duncan JL. Longitudinal study of cone photoreceptors during retinal degeneration and in response to ciliary neurotrophic factor treatment. Invest Ophthalmol Vis Sci. 2011 Apr 6;52(5):2219-26. doi: 10.1167/iovs.10-6479.

    PubMed 21087953

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing NT-501 in people with Retinitis Pigmentosa, run by Neurotech Pharmaceuticals at 12 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 1 May 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 12 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 1 May 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Humphrey Visual Fields - Total Sensitivity (time frame: 12 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00447980, which also lists 3 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 May 2025.

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