US stem cell company given green light for blindness trials

US company StemCells Inc have received Food and Drug Administration (FDA) authorisation to carry out clinical trials of their treatment for a leading cause of blindness in over 55-year-olds.

This is the latest in a number of clinical trials assessing the potential use of stem cells as a treatment for dry age-related macular degeneration (AMD), which affects around 30 million people worldwide.

StemCells Inc's treatment, which injects purified central nervous system (CNS) stem cells into the patient's retina, has been approved for phase I/II clinical trials to assess its safety and efficacy.

A total of 16 patients will be enrolled in this trial, and they will receive standard ophthalmological examinations throughout the first year. A separate observational study will then assess the patients over the subsequent four years.

There is currently no cure or treatment for dry AMD, although some trials are attempting to delay the vision loss process. It is caused by the degeneration of the cells below the retina in the eye, which causes a loss of photoreceptors and eventually blindness.

Approval was given following positive results in initial tests using a well-established rat model of retinal disease. Study author Dr Raymond Lund said that in this study, published in the European Journal of Neuroscience, 'the effect on vision was long-lasting and correlated with the survival of [stem cells] more than seven months after transplantation'. Furthermore, there was no evidence of any uncontrolled, tumour-like cell growth, an important result in terms of clinical use.

Recently biotech company Advanced Cell Technology and the Jules Stein Eye Institute at the University of California, Los Angeles reported positive results in clinical trials of stem cell injections to treat two different types of eye disease (reported in BioNews 642).

StemCells Inc has already begun clinical trials with purified stem cells in patients paralysed from spinal cord injuries and also for children with Pelizaeus-Merzbacher disease, a rare degenerative disorder of the central nervous system.