Safety first with iPS transplants

Apanel of the health and welfare ministry on June 26 approved the world’s first clinical research to transplant human induced pluripotent stem (iPS) cells, which can grow into any type of human body tissue. The transplant is expected to be made next year to six patients suffering from age-related macular degeneration in the exudative form, a condition that may cause a sudden loss of vision due to retinal damage.

Mr. Shinya Yamanaka, a Kyoto University professor who co-won the 2012 Nobel Prize in Physiology or Medicine for his development of iPS cells, announced his discovery in 2007. The panel’s approval came with an unprecedented speed. Too high expectations must not be placed on the clinical research, the main purpose of which is to confirm the safety of the transplant, not the effectiveness of the procedure in repairing macular degeneration.

The governmental scientific research institute Riken and the Foundation for Biomedical Research and Innovation won the panel’s approval. The eye disease affects an estimated 700,000 people in Japan. Abnormal, easy-to-break blood vessels multiply in the retina, and bleeding from them damages the macula or the yellow spot in the center of a visual field. As a result, things seen in the center of a visual field appear deformed or blackened. In the worst cases, sufferers can go blind.

Riken’s research team plans to extract skin cells from the six patients, create iPS cells from them, develop them into pigment epithelium of the retina, and transplant them into the patients to see if the transplants cause problems. The biggest issue with iPS cells is the possibility that they could become cancerous. Therefore the panel called on the team to take utmost care to prevent such an outcome. If the iPS cells do become cancerous, the team is expected to burn any tumors that appear with a laser beam. Because of the nature of the clinical research, the team must fully explain the risks to the patients.

Confirming the safety of any new medical technology in clinical research is extremely important. If clinical research at the initial stage is not carried out carefully, the next stage of actually applying the new technology to treatment and proving its effectiveness could be delayed. Researchers of iPS technology must keep in mind that if they are obsessed with the idea of reaching the stage of using it for actual treatment as fast as they can, they will not be able to accumulate an adequate understanding of the technology.

The Abe administration hopes that regenerative medicine and drug development will serve as an engine for economic growth, and plans to spend ¥110 billion on related projects. Given the rising competition Japan faces in a number of economic sectors it traditionally dominated, the plan is understandable. But safety should remain a top priority. The government should refrain from pressuring researchers into hastily carrying out their studies.

For its part, the Riken team should make public as much of the data acquired from its iPS cells clinical research as possible to help improve the quality of related studies both in Japan and abroad.