Photo/IllutrationNobel laureate Shinya Yamanaka, director of Kyoto University’s Center for iPS Cell Research and Application (Asahi Shimbun file photo)

Researchers involved in clinical trials on new treatments using induced pluripotent stem (iPS) cells need to ensure that sufficient medical data will be gathered to establish the safety and efficacy of iPS cell-based therapies.

A clinical trial to treat Parkinson’s disease patients with iPS cells is set to begin at Kyoto University as its plan for the trial has been accepted by the Pharmaceuticals and Medical Devices Agency (PMDA), the Japanese regulatory agency that oversees clinical trials. The university’s team has started recruiting patients for transplanting nerve cells produced from human iPS cells into their brains.

The researchers say they will work with pharmaceutical companies to establish a new iPS cell-based therapy that is eligible for the public health care insurance program so that it will be affordable and accessible for any patients.

In May, Osaka University’s plan to conduct clinical studies to treat heart failure using sheets of cardiac muscle cells created from iPS cells was approved.

Since the first trial of iPS cells in a human in 2014, which involved using laboratory-made retina cells to treat age-related macular degeneration, the scope of target diseases for the approach has widened to include heart and brain problems.

During the 10 or so years since a technique to “reprogram” any adult cell and bring it back to its earliest “pluripotent” stage was discovered, research on the use of iPS cells, which can theoretically differentiate into any of the body’s specialized cells, for medical treatments has made unusually rapid progress.

Japan has been failing to lead efforts to turn achievements in basic medical research into practical treatments due mainly to shortages of human resources, facilities and funding. It is encouraging to see Japan gradually catching up in this area.

But regenerative medicine therapies using iPS cells entail the risk of implanted cells turning cancerous.

In one clinical study case of using iPS cells to treat the retina disease, researchers called off the planned transplantation after detecting a mutation in the cells that was hard to assess.

There is no past case in which nerve cells produced by iPS cells were transplanted into the brain. The Kyoto University project requires researchers involved to place greater importance on safety than usual in making decisions.

From the viewpoint of future eligibility for the public health care insurance program, the researchers need to evaluate the cost-effectiveness as well as the efficacy of the treatment.

Experiences in the retina treatment studies are instructive again. Initially, iPS cells produced from the patient’s own cells were used. But this approach turned out to be too costly and time-consuming because of the necessary safety checks and preparations.

This time, the Kyoto University team plans to use neurons created from preserved iPS cells that have an immunity type that carries less risk of rejection.

Even this approach, however, will not make the therapy sufficiently affordable, some experts say. The challenge for the researchers is how to overcome this obstacle.

Partly because the iPS cell technology was pioneered by Japanese researcher Shinya Yamanaka, who won a Nobel Prize for his research, Japan has been leading the world in iPS cell research.

In some areas, however, researchers in other countries have made significant progress in the use of embryonic stem cells and stem cells within the body for treatments.

Japan should craft a flexible strategy based on the global trend in stem cell research instead of focusing solely on the iPS cell method.

Prime Minister Shinzo Abe’s administration is seeking to stimulate economic growth by promoting exports of regenerative medicine technologies and products based on iPS cells.

The administration plans to spend 110 billion yen ($992.14 million) in the 10 years from fiscal 2013 and conduct clinical studies and trials on iPS cell-based treatments for 35 diseases by 2020.

But government efforts to drive scientific research for commercial purposes could be risky.

The government should instead focus on long-term policy support to remove unreasonable obstacles to actual studies and applications.

It should not be forgotten that such steady, albeit low-key, policy efforts will be more helpful for making progress in scientific research in medicine and other areas over the long term.

--The Asahi Shimbun, Aug. 17