CHA Bundang Medical Center has become the first in Asia (the second in the world) to confirm that the transplantation of human embryonic stem cell (hESC)-derived retinal pigment epithelium (RPE) cells is effective in treating age-related macular degeneration (AMD) and Stargardt disease (juvenile macular degeneration) without causing dangerous side effects. Hence CHA Bundang Medical Center is now on the fast track to developing the world’s first hESC-based therapeutic product.
A Korean research team, led by Professor Song Won-Kyung from CHA Bundang Medical Center, and CHA Biotech (a leading S. Korea-based biotechnology firm focused on stem cell therapies) jointly issued an interim report on their clinical trial of a human embryonic stem cell (hESCs)-based therapy for retinal diseases and the report was published in the journal Stem Cell Reports, the world's leading platform for high quality peer-reviewed full-text papers, according to CHA Biotech.
The research team said four patients with age-related macular degeneration (AMD) did not show any signs of worrisome side effects after they had received their hESC-based cell therapy. And observing the four patients for a period of 12 months after the sub-retinal transplantation of hESC-derived retinal pigment epithelium (RPE) cells, the research team saw three of them show signs of visual improvements. The announcement of clinical results from this kind of hESCs-based therapy is the first in Asia and the second in the world after the US’s Ocata Therapeutics.
The hESC-based therapy used in their clinical trial was jointly developed by CHA Biotech and Ocata Therapeutics (formerly Advanced Cell Technology). And the Ministry of Food and Drug Safety (MFDS) of S. Korea approved the use of the hESC-based therapy in clinical trials in 2011. The hESC-based therapy revolves around having hESCs, obtained from the frozen embryos left over from fertility treatments, differentiate into RPE cells, which are then directly injected into the eyes of patients with AMD or Stargardt disease.
The study published in Stem Cell Reports also features the research team’s 12-month post-transplantation follow-up assessment of the four patients (two with AMD and the other two with Stargardt disease). None of the four exhibited serious side effects seen with other stem cell therapies and three of them actually had their vision improved.
The ETDRS charts (an international standard for visual acuity measurements that was used in the Early Treatment of Diabetic Retinopathy Study in 1982) were used in measuring the patients’ vision. Visual acuity improved by 9 to 19 letters in the three patients. One of them, who could read only one letter before the clinical trial, was able to read 13 letters.
The four patients were injected with the smallest dose (50,000 cells) of hESC-derived RPE cells. Thus, injections of 100,000 to 200,000 hESC-derived RPE cells are expected to have more dramatic effects on patients with AMD or Stargardt disease.
“Although the clinical trial was aimed at confirming the safety of the transplantation of hESC-derived RPE cells, we saw positive changes in the patients. And the side effects from the transplantation of hESC-derived RPE cells were as mild as those seen with general eye surgeries or the use of immunosuppressants. Either tumorigenicity or immune rejection, feared to appear after the transplantation of hESC-derived cells, was not found. We will continue our clinical research to confirm the efficacy of this hESC-based therapy,” said Professor Song Won-Kyung from CHA Bundang Medical Center.
by Lee Jae-seung