A patient has undergone pioneering stem-cell therapy to treat Parkinson’s disease, the Japanese drugmaker behind the treatment said on Friday, in a world first following its conditional approval in the country.

Sumitomo Pharma’s treatment involves transplanting millions of induced pluripotent stem (iPS) cells, which have the potential to develop into any cell in the body, into a patient’s brain.

Japanese regulators approved the therapy in March, following a successful clinical trial.