Stem cell trial to treat blindness launched in US

Two clinical trials to test whether embryonic stem cells (ES cells) can treat two incurable eye disorders have been launched in the USA. Twenty-four people will be treated during the trials at the Jules Stein Eye Institute at the University of California, Los Angeles (UCLA). One trial will target dry age-related macular degeneration (AMD), the commonest form of blindness in the developed world and a leading cause of vision loss in people aged 55 and over. The other will treat people with Stargardt's macular dystrophy, an inherited condition that usually develops between the ages of 10 and 20.

Professor Steven Schwartz, who will lead the trials at the Institute, said they 'will mark a significant step towards addressing what is one of the largest unmet medical needs of our time…otherwise untreatable and common forms of legal blindness'. He added: 'The incidence of dry AMD is expected to double over the next 20 years as the population ages'.

Both conditions are caused by the progressive loss of retinal pigment epithelial (RPE) cells, which are found in the eye and support, protect and nourish the light-sensitive cells that provide vision. Patients in the trial will receive eye injections of ES cells programmed to behave like RPE cells. The therapy, developed by Advanced Cell Technology (ACT) in Massachusetts during the past decade, has reportedly produced promising results in rats and mice.

Four different doses of cells will be trialled for each disorder — each on a different group of three people. The programme's initial goal is testing the therapy's safety and tolerability and assessing whether the disorders' progression can be slowed. If successful, future trials will investigate halting or reversing the effects of these disorders.

Professor Schwartz explained: 'This trial will begin the process of understanding whether stem cell-derived RPE cells have the potential to be a safe and effective treatment for these debilitating diseases'.

These trials form the second US programme to investigate the use of human ES cells in medical treatments. The first, run by California-based company Geron, began last year and aims to use ES cells to treat paralysis. 'Initiating these two clinical trials represents an important milestone for ES cell research', said Dr Robert Lanza, chief scientific officer at ACT. 'We hope that these cells will, in the future, provide treatment for not only these two untreatable diseases… but for patients suffering from a range of other [eye disorders]'.