TTT Versus PDT for Treatment of Choroidal Neovascularization in Age-Related Macular Degeneration

February 2, 2006 updated by: St. Erik Eye Hospital

Transpupillary Thermotherapy Versus Photodynamic Therapy Treatment of Occult and Minimally Classic Choroidal Neovascularization in Age-Related Macular Degeneration.

The purpose of the study is to compare photodynamic therapy to transpupillary thermotherapy as a treatment method for choroidal neovascularization in age-related macular degeneration ( AMD). AMD is a disease affecting the macula, the central area of the retina.There are two main types of AMD. Geographic atrophy ( dry) AMD and neovascular ( wet) AMD. In neovascular AMD, sub-retinal neovascular membranes ( new blood vessels) develop beneath the retina. The new vessels can leak causing haemorrhage that leads to significant visual loss. Photodynamic therapy ( PDT) is a method for treating neovascular membranes without affecting the retina. Photoactive chemicals are injected into the patient and irradiated with light as the pass through the neovascular membranes. This light is strong enough to activate the chemicals, that destroy the blood vessels, but not strong enough to cause damage to the overlying retina. The duration of the treatment is 83s. PDT treatment is effective in predominantly classic subfoveal choroidal neovascularization ( CNV), but was observed to yield no visual benefit in minimally classic CNV during a 2-year follow-up and as to occult CNV the effect was scarce. PDT does have its drawbacks, one of which is the cost. Another is that the patient become highly sensitive to strong light. Transpupillary thermotherapy ( TTT) is a thermic treatment of choroidal neovascularization in AMD. Using a thermal diode laser ( emission 810 nm), transpupillary irradiation of the fundus through a conventinal contact lens is performed. The temperature is elevated < 10 degrees C during a 60s exposure to continuous radiation. The laser power is adjusted to the diameter of the laser beam. In a pilot study, Reichel et al. ( 1999) demonstrated that subfoveal occult CNV could be occluded and visual acuity stabilized in a majority of patients treated with TTT. These results has been confirmed in small series of cases with occult CNV and with minimally ( <50%) classic CNV. This prospective, randomized controlled study aim to compare TTT and PDT as a treatment for occult and minimally classic CNV. A total of 140 patients will be included in the study. Follow up is 2 years. The patients included will be followed as to visual acutiy ( ETDRS), new vessel growth ( fluorescien angiography and ICG), OCT and with a quality of life questionnarie.

Study Overview

Status

Status

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

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

Age-related macular degeneration ( AMD) is a disease affecting the macula, the central area of the retina. There are two main types of AMD. Geographic atrophy ( dry) AMD and neovascular ( wet) AMD. In neovascular AMD, subretinal neovascular membranes develop beneath the retina. The new vessels can leak causing haemorrhage that leads to edema, scarring and significant visual loss. Sub-retinal neovasular membranes are defined as classic, occult and minimally classic according to their apperance on fluorescein angiography. Trials have shown that early laser photocoagulation of classic extrafoveal lesions could delay the loss of vision in a small number of patients. However, most patients present with subfoveal membranes and whilst photocoagulation can limit the extent of subsequent visual loss, it causes immediate loss of central vision due to concurrent destruction of the overlying retina. Photodynamic theray ( PDT) represent a milestone in the treatment of CNV, and marks the start of a new era. Current PDT operates on the basis of principal that makes use of a dye ( verteporfin) which is preferentially retained in proliferating tissue such as CNV, sensitizing the endothelial cells to laser rediation ( 689 nm). Endothelial cells degeneration is mediated by reactive oxygen which intermediates with subsequent platelet activation, and a thrombosis, and temporary or permanent occlusion of vessels is seen in the treated area ( Ghazi et al 2001. The light is strong enough to activate the chemicals, causing them to emit free radicals that destroy the blood vessles, but not strong enough to cause damage to the overlying retina. The duration of the treatment is 83s. PDT is effective in predominantly classic subfoveal CNV, but was observed to yield no visual benefit in minimally clasic CNV during a 2-year follow-up. As to occult CNV PDT was effective in small lesions ( 4 disc areas or less), when there was a recent disease progress and when visual acuity was less then 20/50. In the VIP ( Verteporfin Therapy of Subfoveal Choroidal neovascularization, 2 year resulta of Randomized Clinical trial incl Lesion with Occult with no classic CNV) the primary outcome, visual acuity, was similar for the verteporfin-treated and the placebo-treated eyes through the month 12 examination. Between the month 12 and 24 rxminations, the treatment benefit grew so that by the month 24 examination, the verteporfin-treated eyes were less likely to have moderate or severe vision loss. PDT does have its drawbacks, ont is the cost. Another that the patient become highly sensitive to strong light and needs to wear special sunglasses for 48 hrs after treatment. There has also been discussions regarding lesion size and the potential of damage due to re-treatments.

Transpupillary thermotherapy ( TTT) is a thermic teratment of CNV in AMD. Using a thermal diode laser ( emission 810nm), transpupillary irradiation of the fundus through a conventional ( laser) contact lens is performed. The irradiation is resorbed mainly in the melanin granules of RPE and choroidal melanocytes and there is little absorption in the neurosensory retina. The temperatures in the layers of RPE and choriocapillaris is elevated < 10 degrees C during a 60s exposure to continuous rediation. High rates of resportion of the radiation in the endothelium of growing, newly formed vessels will result in thrombus formation and delayed closure of the CNV. The power is adjusted to the diameter of the laser beam. Laser power of 400 mW for a 2.0 mm spot, was found to be safe for the retina in human eyes ( Conolly et al 2001). In a pilot study, Reichel et al ( 1999) demonstrated that subfoveal occult CNV could be occluded and visual acuity stabilized in a majority of patients treated with TTT. These results has been confirmed in small series of cases.

This prospective, randomized controlled study aim to compare PDT and TTT as a treatment for occult and minimally classic CNV. A total of 140 patients will be included in the study, ( 110 patients are presently included). Follow up is 2 years. The main outcome is visual acuity ( ETDRS), new vessel growth ( fluorescein angiography and ICG), retinal thickness ( OCT. Furtermore patients will participate in a quality of life questionnarie ( National Eye Institute Visual Function Questionnarie, NEI-CFQ-25).

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.
Interventional

Enrollment

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.
140

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 3

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Sweden
      • Stockholm, Sweden, 16773
        • Recruiting
        • St Eriks Eye Hospital
        • Contact:
        • Principal Investigator:
          • Anne C Odergren, MD

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

50 years to 85 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria: Informed consent. Occult or minimally classic choroidal neovascularization. Lesion size < 5 mm. VA 0.1-0.5. Recent disease progress.

< 25% subretinal fibrosis. No contraindications to fluoresceinangiography and ICG.

-

Exclusion Criteria: Earlier treatment with argonlaser or PDT, or otherwise treated in the eye with radiation or PPV. Submacular hemorrhage > 50%. Serous PED > 25%. Geographic atrophy > 1 disc and < 500 um from fovea. Chorioretinal anastomosis. Glaucoma. Diabetes retinopathy with > 5 microaneurysm. Contraindications to fluoresceinangiography or ICG. Enrollment in other studies. Drugaddiction.

-

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
  • Masking: SINGLE

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
Visual acuity, base, 6 weeks, 3 months, 4,5 months, 6 months, 9 months, 12 months, 18 months, 24 months.

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
New vessel growth
Retinal thickness

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.
St. Erik Eye Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Anne C Odergren, MD, St Eriks Eye Hospital
  • Study Chair: Stefan Seregard, Professor, St Eriks Eye Hospital

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

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 1, 2003

Study Completion

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.
January 1, 2008

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).
November 29, 2005

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.
November 29, 2005

First Posted (ESTIMATE)

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.
December 1, 2005

Study Record Updates

Last Update Posted (ESTIMATE)

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.
February 3, 2006

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.
February 2, 2006

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, 2004

More Information

Terms related to this study

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.
  • 95/00
  • Dnr 2005/19-32

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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