Policy & Regulation
Gyroscope Therapeutics Initiates Phase II Programme Evaluating its Investigational Gene Therapy, GT005, for Dry Age-Related Macular Degeneration
13 August 2020 - - UK-based retinal gene therapy company Gyroscope Therapeutics Ltd has initiated its Phase II programme evaluating its investigational gene therapy, GT005, for the treatment of geographic atrophy secondary to dry age-related macular degeneration, the company said.

Dry AMD is a leading cause of permanent vision loss in people over the age of 50.

GT005 is a one-time AAV-based gene therapy that is delivered under the retina. The goal of the Phase II clinical trial programme is to determine if GT005 has the potential to slow the progression of GA.

Gyroscope plans to conduct two Phase II trials evaluating GT005 in people with GA. The first, called EXPLORE, is enrolling people who have a mutation in their Complement Factor I gene [NCT04437368]. The first patient to receive GT005 in EXPLORE was enrolled and dosed by Dr. Arshad M. Khanani at Sierra Eye Associates in Reno, Nev., USA.

GT005 is designed to restore balance to an overactive complement system, a part of the immune system, by increasing production of the CFI protein.

An overactive complement system has been implicated in the development of AMD. The CFI protein regulates the activity of the complement system.

It is believed that increasing CFI production will dampen the system's overactivity and reduce inflammation, with the goal of preserving a person's eyesight.

Research has found that approximately 3% of people with dry AMD have certain CFI mutations that correlate with low CFI levels in the blood and a higher risk of developing AMD.

Gyroscope estimates that more than 100,000 people with GA in the United States and EU5 European countries may have these mutations.

The EXPLORE trial will evaluate GT005 in this group of people with mutations in their CFI gene.

Research has also shown that a small supplementation of CFI can normalise complement activity in the blood,5 suggesting GT005 may also be applicable for a broader group of people with GA.

It is estimated that approximately 1m people in the United States alone have GA.4 Gyroscope therefore plans to initiate a second Phase II trial in 2020 that will evaluate GT005 in a broader GA population.

EXPLORE is a Phase II, multicentre, randomised trial evaluating the safety and efficacy of GT005 administered as a single subretinal injection.

EXPLORE is enrolling people who are aged 55 or older and have a clinical diagnosis of GA secondary to dry AMD and who have a mutation of the CFI gene.

People being screened for the trial will be genotyped for the mutations.

Trial participants will be randomised to one of three treatment arms: GT005 dose 1, GT005 dose 2 or a control arm.

Participants in the control arm will receive current standard of care. The primary endpoint of EXPLORE is progression of GA over 48 weeks.

The study will also evaluate GT005 for various safety and tolerability measures. Gyroscope plans to enroll approximately 75 patients at approximately 40 centres based in the United States, United Kingdom, Europe and Australia.

Gyroscope will announce details about the second Phase II trial of GT005 at a later date.

AMD is a leading cause of blindness affecting an estimated 196m people globally.6 AMD typically affects people aged 50 and older, and causes a gradual and permanent loss of central vision that worsens over time.

There are no approved treatments for the dry form of AMD, which is the most common, impacting approximately 90% of people with the disease.

As dry AMD advances it leads to GA, an irreversible degeneration of retinal cells. This vision loss can be devastating, severely impacting a person's daily life as they lose the ability to drive, read and even see the faces of loved ones.

Gyroscope Therapeutics is a clinical-stage retinal gene therapy company developing and delivering gene therapy beyond rare disease to treat a leading cause of blindness, dry AMD.