Glaucoma, Open-AnglePhase 2NCT02376114
Ginkgo Biloba and Ocular Blood Flow in Primary Open-angle Glaucoma
A Phase 2 study testing Ginkgo biloba in people with Glaucoma, Open-Angle, run by Maisonneuve-Rosemont Hospital at 1 site in Canada.
Trial summary
Glaucoma is one of the leading causes of blindness. Ginkgo biloba may be part of an effective treatment strategy for glaucoma because it has been shown to improve blood flow, it has antioxidant properties, it can relax smooth muscle, and it can protect neurons from damage. Read more about this study
- Who is it for?
- Ages 40 to 80 years
- Conditions the study is for
- Glaucoma, Open-Angle
- What is being tested?
- Ginkgo biloba
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 19 participants
- Where
- 1 siteCanada
- Study dates
- Aug 2011to Feb 2014
- Phase
- Phase 2
- Are there results?
- None posted in the registry
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 40 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- We focused this trial on vasospastic glaucoma patients because we believed that these would be the patients most likely to benefit from the ability of Ginkgo to improve blood flow.
- Patients who had been identified from previous research as being vasospastic on the Transonic Laser Doppler Flowmeter (Transonic Systems Inc., Ithaca, NY) were contacted and asked if they would like to participate in the trial.
- We recruited vasospastic patients with early or moderate primary open-angle glaucoma with a typical visual field defect with an abnormal Glaucoma Hemifield Test and a Mean Deviation worse than -2 decibels, and an optic nerve head showing retinal nerve fiber layer or neuroretinal rim loss characteristic of glaucoma.
- There was no restriction for intraocular pressure at time of diagnosis although at the time of recruitment intraocular pressure had to be effectively controlled either by ocular hypertension therapy or by surgery.
- If a patient had two eyes eligible, data from the right eye only was used.
Who cannot join
- those taking anticoagulant therapy,
- those with blood disorders or diabetes,
- women who were pregnant, planning to become pregnant, or who were breast-feeding,
- patients with a history of seizures or who were currently taking anti-convulsant medication, and
- those who could not return for 2 follow-up visits at 4 and 6 weeks.
- those patients who are already taking Ginkgo were asked if they were willing to stop for 6 weeks before the study.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effect of Ginkgo Biloba on Ocular Blood Flow in Primary Open-Angle Glaucoma Patients: A Double-Blind Randomized Crossover Trial
Glaucoma is one of the leading causes of blindness. Ginkgo biloba may be part of an effective treatment strategy for glaucoma because it has been shown to improve blood flow, it has antioxidant properties, it can relax smooth muscle, and it can protect neurons from damage. The goal of our study was to determine whether Ginkgo biloba would result in increased ocular blood flow which may protect against glaucoma damage.
Read the detailed description
Glaucoma is one of the leading causes of blindness. Glaucoma progression sometimes occurs despite apparent control of intraocular pressure. Therefore, there may be other factors involved in glaucoma progression in some patients. Evidence is mounting that glaucoma patients are more likely to have abnormal ocular blood flow and vasospasm compared to those without glaucoma. Also, a study showed that those with progressive glaucoma had decreased blood flow compared to those with stable glaucoma or healthy controls. Endothelin-1, a potent vasoconstrictor, may be involved in these blood flow abnormalities. If the dysregulation of blood flow is causally related to the progression of glaucoma, then therapies aimed at improving the regulation of blood flow may help to prevent this progression.
Ginkgo may be part of an effective treatment strategy for glaucoma because it has been shown to improve peripheral and cerebral blood flow. Other properties of Ginkgo that may aid in the treatment of glaucoma include antioxidant properties, inhibition of platelet activating factor, relaxation of smooth muscle, and neuroprotective properties. Ginkgo may be particularly useful in relaxing vasospasm. Two controlled trials have examined the effect of Ginkgo on ocular blood flow in healthy subjects. One randomized crossover trial found that 2 days of Ginkgo increased the end diastolic velocity in the ophthalmic artery compared to placebo. However, another trial found that 1 dose of Ginkgo had no significant effects on ocular blood flow parameters. In people with normal tension glaucoma, Park et al found that 4 weeks of Ginkgo increased peripapillary retinal blood flow. Two randomized controlled trials have examined the impact of Ginkgo biloba on visual field in people with normal tension glaucoma with conflicting results. Clearly, there is a need for more research on this topic.
The goal of our study was to determine whether Ginkgo biloba would result in increased ocular blood flow, reduced vasospasm, and reduced endothelin-1 levels.
- Conditions
- Glaucoma, Open-Angle
- Being tested
- Ginkgo biloba, Placebo to Ginkgo biloba
- Keywords
- ocular blood flow, ginkgo biloba, glaucoma, vasospasm
- Medical subject headings
- Glaucoma, Open-Angle, Glaucoma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Ginkgo bilobaDrug
The Ginkgo biloba extract that was used contained 24% ginkgo flavone glycosides and 6% terpene lactones (Vitamin Research Products, Carson City, Nevada). Patients took 60 mg of Ginkgo or a placebo twice daily by mouth for two weeks. The placebo consisted of 40 mg of corn starch. Ginkgo and the placebo were encapsulated to ensure identical appearance.
Placebo to Ginkgo bilobaDrug
| Study group | Role | What they receive |
|---|---|---|
| Ginkgo-Placebo | Other | Patients receive Ginkgo biloba and then placebo afterwards. Receives: Drug: Ginkgo biloba |
| Placebo-Ginkgo | Other | Patients receive placebo and then Ginkgo biloba afterwards. Receives: Drug: Placebo to Ginkgo biloba |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter
Change in optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter
Measured: 4 weeks and 10 weeks
Secondary outcomes (4)
Change in retinal blood flow as measured by the Canon Laser Blood Flowmeter
Change in retinal blood flow as measured by the Canon Laser Blood Flowmeter
Measured: 4 weeks and 10 weeks
Change in ocular pulse amplitude as measured with the Pascal Dynamic Contour Tonometer
Change in ocular pulse amplitude as measured with the Pascal Dynamic Contour Tonometer
Measured: 4 weeks and 10 weeks
Change in peripheral vasospasm as measured during the cold provocation test using the Transonic Laser Doppler Flowmeter
Change in peripheral vasospasm as measured during the cold provocation test as measured using the Transonic Laser Doppler Flowmeter
Measured: 4 weeks and 10 weeks
Change in endothelin-1 levels as measured by an enzyme-linked immunosorbent assay kit
Change in endothelin-1 levels as measured by an enzyme-linked immunosorbent assay kit
Measured: 4 weeks and 10 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Mar 2015 (estimated)
- Study startAug 2011
- Primary completionFeb 2014
- Study completionFeb 2014
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Glaucoma, Open-AngleStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- Maisonneuve-Rosemont Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ellen Freeman, Maisonneuve-Rosemont Hospital
- Investigators
- Ellen Freeman, PhD, Principal investigator, Maisonneuve-Rosemont HospitalMark Lesk, MD, Principal investigator, Maisonneuve-Rosemont Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02376114
- Sponsor's protocol ID
- Ginkgo and blood flow
- Status last verified
- Feb 2015
- First submitted
- 24 Feb 2015
- Last updated
- 3 Mar 2015
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Mar 2015. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Ginkgo Biloba on Ocular Blood Flow in Primary Open-Angle Glaucoma Patients: A Double-Blind Randomized Crossover Trial
- ClinicalTrials.gov ID
- NCT02376114
- Acronym / sponsor ID
- Ginkgo and blood flow
- Conditions
- Glaucoma, Open-Angle
- Keywords
- ocular blood flow, ginkgo biloba, glaucoma, vasospasm
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- Maisonneuve-Rosemont HospitalUniversity, hospital or other
- Study start
- Aug 2011
- Primary completion
- Feb 2014 (actual)
- Study completion
- Feb 2014 (actual)
- First posted
- 3 Mar 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Glaucoma is one of the leading causes of blindness. Ginkgo biloba may be part of an effective treatment strategy for glaucoma because it has been shown to improve blood flow, it has antioxidant properties, it can relax smooth muscle, and it can protect neurons from damage. The goal of our study was to determine whether Ginkgo biloba would result in increased ocular blood flow which may protect against glaucoma damage.
Detailed description
Glaucoma is one of the leading causes of blindness. Glaucoma progression sometimes occurs despite apparent control of intraocular pressure. Therefore, there may be other factors involved in glaucoma progression in some patients. Evidence is mounting that glaucoma patients are more likely to have abnormal ocular blood flow and vasospasm compared to those without glaucoma. Also, a study showed that those with progressive glaucoma had decreased blood flow compared to those with stable glaucoma or healthy controls. Endothelin-1, a potent vasoconstrictor, may be involved in these blood flow abnormalities. If the dysregulation of blood flow is causally related to the progression of glaucoma, then therapies aimed at improving the regulation of blood flow may help to prevent this progression.
Ginkgo may be part of an effective treatment strategy for glaucoma because it has been shown to improve peripheral and cerebral blood flow. Other properties of Ginkgo that may aid in the treatment of glaucoma include antioxidant properties, inhibition of platelet activating factor, relaxation of smooth muscle, and neuroprotective properties. Ginkgo may be particularly useful in relaxing vasospasm. Two controlled trials have examined the effect of Ginkgo on ocular blood flow in healthy subjects. One randomized crossover trial found that 2 days of Ginkgo increased the end diastolic velocity in the ophthalmic artery compared to placebo. However, another trial found that 1 dose of Ginkgo had no significant effects on ocular blood flow parameters. In people with normal tension glaucoma, Park et al found that 4 weeks of Ginkgo increased peripapillary retinal blood flow. Two randomized controlled trials have examined the impact of Ginkgo biloba on visual field in people with normal tension glaucoma with conflicting results. Clearly, there is a need for more research on this topic.
The goal of our study was to determine whether Ginkgo biloba would result in increased ocular blood flow, reduced vasospasm, and reduced endothelin-1 levels.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Ginkgo-Placebo | Other | Drug: Ginkgo bilobaPatients receive Ginkgo biloba and then placebo afterwards. |
| Placebo-Ginkgo | Other | Drug: Placebo to Ginkgo bilobaPatients receive placebo and then Ginkgo biloba afterwards. |
Who may qualify
- Ages
- 40 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- We focused this trial on vasospastic glaucoma patients because we believed that these would be the patients most likely to benefit from the ability of Ginkgo to improve blood flow.
- Patients who had been identified from previous research as being vasospastic on the Transonic Laser Doppler Flowmeter (Transonic Systems Inc., Ithaca, NY) were contacted and asked if they would like to participate in the trial.
- We recruited vasospastic patients with early or moderate primary open-angle glaucoma with a typical visual field defect with an abnormal Glaucoma Hemifield Test and a Mean Deviation worse than -2 decibels, and an optic nerve head showing retinal nerve fiber layer or neuroretinal rim loss characteristic of glaucoma.
- There was no restriction for intraocular pressure at time of diagnosis although at the time of recruitment intraocular pressure had to be effectively controlled either by ocular hypertension therapy or by surgery.
- If a patient had two eyes eligible, data from the right eye only was used.
Key exclusion criteria (6 listed)
- those taking anticoagulant therapy,
- those with blood disorders or diabetes,
- women who were pregnant, planning to become pregnant, or who were breast-feeding,
- patients with a history of seizures or who were currently taking anti-convulsant medication, and
- those who could not return for 2 follow-up visits at 4 and 6 weeks.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ginkgo bilobaThe Ginkgo biloba extract that was used contained 24% ginkgo flavone glycosides and 6% terpene lactones (Vitamin Research Products, Carson City, Nevada). Patients took 60 mg of Ginkgo or a placebo twice daily by mouth for two weeks. The placebo consisted of 40 mg of corn starch. Ginkgo and the placebo were encapsulated to ensure identical appearance. | Drug | Ginkgo-Placebo |
| Placebo to Ginkgo biloba | Drug | Placebo-Ginkgo |
Primary outcome
Change in optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter
Time frame: 4 weeks and 10 weeks
Change in optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter
4 secondary outcomes
Change in retinal blood flow as measured by the Canon Laser Blood Flowmeter
Time frame: 4 weeks and 10 weeks
Change in ocular pulse amplitude as measured with the Pascal Dynamic Contour Tonometer
Time frame: 4 weeks and 10 weeks
Change in peripheral vasospasm as measured during the cold provocation test using the Transonic Laser Doppler Flowmeter
Time frame: 4 weeks and 10 weeks
Change in endothelin-1 levels as measured by an enzyme-linked immunosorbent assay kit
Time frame: 4 weeks and 10 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Mar 2015.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ellen Freeman, PhD principal investigator
Maisonneuve-Rosemont Hospital
Mark Lesk, MD principal investigator
Maisonneuve-Rosemont Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Ginkgo biloba in people with Glaucoma, Open-Angle, run by Maisonneuve-Rosemont Hospital at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 6 exclusion criteria. 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 3 Mar 2015. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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 optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter (time frame: 4 weeks and 10 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 3 Mar 2015.