Why is there still no cure for macular disease?

Teams of researchers around the world – including some that our supporters are funding – are attacking macular disease from every angle. So why haven’t we cured it yet?

Geraldine Hoad, Macular Society research manager, explains the long and expensive journey that any treatment must go through before it arrives in your clinic.

On average it takes at least 10 years and over a billion pounds for a new medicine to go from initial discovery to being licenced for use.

It all starts with discoveries in the laboratory, called basic research, to find out what has gone wrong in the normal workings of the eye that led to macular disease. The task is then to design a drug to stop this happening without causing dangerous side effects. It can mean assessing many thousands of potential drugs to find the few worth taking to the next stage: early safety and efficacy tests to see whether the drug can be given to patients. Carefully conducted clinical trials are performed in human volunteers to answer questions such as:

• Does a treatment work?

• Does it work better than other treatments?

• Does it have side effects?

And we have all heard about trials being in ‘phase one’ or ‘phase two’, but what does this actually mean?

Phase one trials aim to test the safety, method of delivery and dose of a new drug. These trials use a small number of people, who may be healthy volunteers. To minimise any risks, the researchers usually start with a small dose and increase it slowly until they get the best results compared with any side effects.

Phase two trials test a drug on a larger group of people who have the condition. These trials aim to get a better idea of whether the drug works and how well it works in the short-term. If enough people benefit and the side effects are still acceptable, the drug can go on to phase three.

Phase three trials use larger groups of people who have the condition and compare the new drug with the existing treatment or a placebo (fake treatment, such as a tablet without any active ingredients). The researchers look at whether the drug works in practice and what the side effects are. Phase three trials can involve thousands of patients across the world and last a year or longer.

If a drug passes phase three and is shown to be safe and effective at treating the disease, the pharmaceutical company will apply to the regulatory authorities for a licence. If a licence is granted, then the drug can be prescribed to patients.

Phase four trials are carried out when a new drug has passed all of the previous stages and been given a marketing licence. The researchers will continue to look at the safety, side effects and effectiveness of the drug in the real world, and see whether there are any new long-term side effects or benefits.

The Macular Society funds medical research so that one day we can overcome macular disease. We have helped fund groundbreaking developments in areas including stem cell treatment. Find out more about some of the projects we are currently funding. 

We are often approached for volunteers to participate in clinical trials and research studies. Our research participant database is for anyone with a macular condition, as well as healthy family members and volunteers. You can sign up to hear about research opportunities whether or not you are a member of the Macular Society by completing the form at www.macularsociety.org/database.