Phosphodiesterase Inhibitors in Glaucoma Study (PhiGS)

NCT04052269 | Suspended Phase 3

• 1 other identifier: 19/WE/5104
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

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.

Conditions

Glaucoma

Keywords

Glaucoma

Outcome Measures

Primary Outcomes (6)

• Changes in central macular thickness as assessed by retina imaging

  OCT and angiographic findings before and after drug administration including

  30 minutes, 60 minutes, 120 minutes

• Changes in retinal vascular density as assessed by retina imaging

  OCT and angiographic findings before and after drug administration including

  30 minutes, 60 minutes, 120 minutes

• Changes in outer retina flow as assessed by retina imaging

  OCT and angiographic findings before and after drug administration including

  30 minutes, 60 minutes, 120 minutes

• Changes in choroidal vascular density as assessed by retina imaging

  OCT and angiographic findings before and after drug administration including

  30 minutes, 60 minutes, 120 minutes

• Changes in central choroidal thickness as assessed by retina imaging

  OCT and angiographic findings before and after drug administration including

  30 minutes, 60 minutes, 120 minutes

• Changes in choroidal flow as assessed by retina imaging

  OCT and angiographic findings before and after drug administration including

  30 minutes, 60 minutes, 120 minutes

Study Arms (2)

eyes with glaucoma

EXPERIMENTAL

patients with glaucoma will have imaging of retina post administration of Sildenafil or Tadalafil.

Drug: Sildenafil 100mg

Healthy (unaffected) eyes

OTHER

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

Interventions

Sildenafil 100mg DRUG

study drug (Sildenafil or Tadalafil) administered orally in pill form with glass of water.

Also known as: Tadalafil

Healthy (unaffected) eyes; eyes with glaucoma

Eligibility Criteria

• Age: 40 Years - 80 Years
• Sex: male
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Imperial College London: lead

Study Sites (1)

Western Eye Hospital

London, NW1 5QH, United Kingdom

Location

MeSH Terms

Conditions

Glaucoma

Interventions

Sildenafil Citrate; Tadalafil

Condition Hierarchy (Ancestors)

Ocular Hypertension; Eye Diseases

Intervention Hierarchy (Ancestors)

Sulfonamides; Amides; Organic Chemicals; Sulfones; Sulfur Compounds; Piperazines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Carbolines; Pyridines; Indole Alkaloids; Indoles; Heterocyclic Compounds, 3-Ring

Study Officials

• Eduardo Dr Normando, MD, PhD

  Imperial College London

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Healthy vs affected eyes (glaucoma)

Study Record Dates

• First Submitted: August 5, 2019
• First Posted: August 9, 2019
• Study Start: June 21, 2019
• Primary Completion: October 30, 2021
• Study Completion: October 30, 2022
• Last Updated: January 25, 2021

Record last verified: 2021-01

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)