First iPSC clinical trial approved
Japanese scientists have recently announced that a small-scale human clinical trial for therapeutic application of induced pluripotent stem cells (iPSC) in the treatment of age-related macular degeneration (AMD) will take place at the Institute for Biomedical Research and Innovation, together with the RIKEN Center for Developmental Biology, in Kobe, Japan. The trial aims at generating retinal cells that can be transplanted in patients suffering from AMD, which affects older adults and results in degeneration of the retinal tissue with subsequent loss of vision in the center of the visual field.
On Wednesday last week, an institutional review board at the Institute of Biomedical Research and Innovation gave conditional approval to the study, which will be led by Masayo Takahashi of the Center for Developmental Biology. The team will need to submit data from pre-clinical safety trials, which are currently underway. Before starting patient recruitment, the researchers will also need to submit an application with the Health Ministry of Japan. Takahashi said that the clinical trial will enroll only six patients over 50 years of age, and is not expected to halt or reverse the process of degeneration, but is simply meant to demonstrate the safety of the procedure in humans and test the possibility that progress of the disease can be slowed down in this way. The clinical trial may start as early as March 2014.
The procedure will involve surgically removing the damaged epithelium, and replacing it with a layer of iPSC cells derived from the patient’s own epithelial cells. Unlike human embryonic stem cells (hESCs), which are obtained from human embryos and involve destruction of the starting material, a fact that has led to controversy about their use for medical applications, iPSCs can be derived from terminally differentiated epithelial cells. The Japanese scientist Shinya Yamanaka won the Nobel Prize in Physiology and Medicine last year for his discovery in 2006 that by expressing a handful of factors in epithelial cells, these could be forced to revert to a pluripotent stem cell state. Recently, a lab affiliated with the Chinese Academy of Sciences made headlines for generating iPSCs from kidney epithelial cells present in urine. Several studies in the US have been approved to investigate the therapeutic potential of embryonic stem cells in human clinical trials, but the Japanese study will be the first one of its kind in that it will use iPSCs derived from the same patient, instead of stem cells from human embryos. Many scientists believe that using iPSCs will circumvent many of the immunorejection problems that often trouble hESC-based therapies.
Three studies testing human embryonic stem cells in clinical trials for age-related macular degeneration (AMD), Stargardt’s macular dystrophy (SMD), and restoration of spinal cord function in patients with recent spinal cord injuries have been approved in the United States. The first two studies are currently in Phase I safety and tolerability clinical trials, and are being led by biotech company Advanced Cell Technology (ACT), while the third was discontinued by California-based company Geron on November 14th. Clinical trials using stem cells from other sources, such as the bone marrow and spinal cord, have been approved for treatment of several different degenerative conditions.
The NIH has come under fire earlier this month for authorizing usage of embryonic stem cell lines that may have been generated from unconsenting gamete donors. Similarly, Japan has been criticized for its lax legislation regarding stem cell therapy and resulting “stem cell tourism”, whereby visitors from South Korea and other countries attempt to receive unauthorized stem cell-based therapeutic treatments from Japanese private companies.