TOKYO, Japan (AFP) – Japanese drugmaker Sumitomo Pharma said Tuesday it is seeking approval for a Parkinson’s disease treatment that transplants stem cells into a patient’s brain, following a successful clinical trial.

The company applied to Japanese regulators for manufacturing and marketing authorisation aimed at the treatment of patients with advanced Parkinson’s disease, it said in a statement.

A trial led by Kyoto University researchers indicated that the company’s treatment using induced Pluripotent Stem (iPS) cells — which have the potential to develop into any cell in the body — was safe and successful in improving symptoms.

The study involved seven Parkinson’s patients aged between 50 and 69, with each receiving a total of either five million or 10 million cells implanted on both sides of the brain.

The iPS cells from healthy donors were developed into the precursors of dopamine-producing brain cells, which are no longer present in people with Parkinson’s disease.

The patients were monitored for two years and no major adverse effects were found, the study said. Four patients showed improvements in symptoms, it said.

The trial results were published in Nature in April.

Sumitomo Pharma is also carrying out a clinical trial in the United States.

Parkinson’s disease is a chronic, degenerative neurological disorder that affects the body’s motor system, often causing shaking and other difficulties in movement.

Worldwide, about 10 million people have the illness, according to the Parkinson’s Disease Foundation.

Currently available therapies “improve symptoms without slowing or halting the disease progression,” the foundation says.

iPS cells are created by stimulating mature, already specialised, cells back into a juvenile state — basically cloning without the need for an embryo.

The cells can be transformed into a range of different types of cells, and their use is a key sector of medical research.