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Phosphodiesterase Inhibitors in Glaucoma Study (PhiGS) (PhiGS)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT04052269
Recruitment Status : Suspended (suspended due to COVID)
First Posted : August 9, 2019
Last Update Posted : January 25, 2021
Sponsor:
Information provided by (Responsible Party):
Imperial College London

Brief Summary:

It is commonly known that high eye pressure is associated with glaucoma. However, there is also a theory that poor circulation to the eye is a contributing factor. Therefore, if we can increase the flow of blood to the eye, we may be able to stop people losing vision from this disease.

Phosphodiesterase inhibitors (for example sildenafil, tadalafil, Viagra®, Cialis®) are drugs used to improve blood flow to certain parts of the body. They are commonly used on an ad-hoc basis to treat erectile dysfunction, in addition to problems with blood circulation to the lungs, fingers and toes.

The majority of previous work in this field has been completed using insensitive, poorly reproducible techniques such as colour doppler ultrasound. Since then, a new imaging modality able to image blood flow in blood vessels without the need for the injection of contrast has entered clinical use.

This initial pilot study is designed as a proof-of-concept study to investigate whether we can measure detectable changes in the blood flow to the retina and choroid at the back of the eye following ingestion of a phosphodiesterase inhibitor medication by healthy and glaucomatous volunteers already taking this medication for erectile dysfunction.


Condition or disease Intervention/treatment Phase
Glaucoma Drug: Sildenafil 100mg Phase 3

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 30 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: Healthy vs affected eyes (glaucoma)
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: A Pilot Study to Investigate the Effect of Phosphodiesterase Inhibitors on Chorioretinal Blood Flow Using Optical Coherence Tomography Angiography.
Actual Study Start Date : June 21, 2019
Estimated Primary Completion Date : October 30, 2021
Estimated Study Completion Date : October 30, 2022

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Glaucoma

Arm Intervention/treatment
Experimental: eyes with glaucoma
patients with glaucoma will have imaging of retina post administration of Sildenafil or Tadalafil.
Drug: Sildenafil 100mg
study drug (Sildenafil or Tadalafil) administered orally in pill form with glass of water.
Other Name: Tadalafil

Healthy (unaffected) eyes
patients with healthy eyes who are already taking Sildenafil or Tadalafil have their imaging of retina post administration of Sildenafil or Tadalafil.
Drug: Sildenafil 100mg
study drug (Sildenafil or Tadalafil) administered orally in pill form with glass of water.
Other Name: Tadalafil




Primary Outcome Measures :
  1. Changes in central macular thickness as assessed by retina imaging [ Time Frame: 30 minutes, 60 minutes, 120 minutes ]
    OCT and angiographic findings before and after drug administration including

  2. Changes in retinal vascular density as assessed by retina imaging [ Time Frame: 30 minutes, 60 minutes, 120 minutes ]
    OCT and angiographic findings before and after drug administration including

  3. Changes in outer retina flow as assessed by retina imaging [ Time Frame: 30 minutes, 60 minutes, 120 minutes ]
    OCT and angiographic findings before and after drug administration including

  4. Changes in choroidal vascular density as assessed by retina imaging [ Time Frame: 30 minutes, 60 minutes, 120 minutes ]
    OCT and angiographic findings before and after drug administration including

  5. Changes in central choroidal thickness as assessed by retina imaging [ Time Frame: 30 minutes, 60 minutes, 120 minutes ]
    OCT and angiographic findings before and after drug administration including

  6. Changes in choroidal flow as assessed by retina imaging [ Time Frame: 30 minutes, 60 minutes, 120 minutes ]
    OCT and angiographic findings before and after drug administration including



Information from the National Library of Medicine

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Ages Eligible for Study:   40 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Able to give informed consent to participate in the study
  • Aged between 40 and 80 years of age
  • Clear optical media
  • Spherical equivalent +-10D
  • IOP 21mmHg

Exclusion Criteria:

  • have used sildenafil for 48 hours (4 hour half-life) and tadalafil for 5 days (48 hour half-life).
  • have a known adverse reaction to any phosphodiesterase inhibitors
  • have an inherited photoreceptor disease (manufacturer contra-indication)
  • have any other known ocular disease (except glaucoma in this cohort)
  • have had non-arteritic anterior ischaemic optic neuropathy (manufacturer precaution due to lack of long term visualfield studies)
  • are on current ritonavir, erythromycin, cimetidine treatment (Manufacturer advises if concurrent use of ritonavir is unavoidable, the max. dose should not exceed 25 mg within 48 hours)
  • have serious cardiac or liver disease (manufacturer contra-indication)
  • have had a stroke or myocardial infarction (manufacturer contra-indication) within 6 months
  • have anatomical deformation of the penis or conditions predisposing to priapism (sickle cell anaemia, leukaemia, multiple myeloma)
  • have hypotension (manufacturer contra-indication) BP<100/60
  • have secondary or narrow/closed angle glaucoma

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04052269


Locations
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United Kingdom
Western Eye Hospital
London, United Kingdom, NW1 5QH
Sponsors and Collaborators
Imperial College London
Investigators
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Principal Investigator: Eduardo Dr Normando, MD, PhD Imperial College London
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Responsible Party: Imperial College London
ClinicalTrials.gov Identifier: NCT04052269    
Other Study ID Numbers: 19/WE/5104
First Posted: August 9, 2019    Key Record Dates
Last Update Posted: January 25, 2021
Last Verified: January 2021
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by Imperial College London:
Glaucoma
Additional relevant MeSH terms:
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Glaucoma
Ocular Hypertension
Eye Diseases
Sildenafil Citrate
Tadalafil
Vasodilator Agents
Phosphodiesterase 5 Inhibitors
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Urological Agents