A Trial to Determine the Safety and Tolerability of Transplanted Stem Cell Derived Dopamine Neurons to the Brains of Individuals With Parkinson's Disease

Parkinson's disease (PD) occurs when an area of the brain begins to lose nerve cells that produce a chemical called dopamine. Dopamine is an important chemical, and one of its functions is that it helps to regulate body movement. The loss of these nerve cells leads to a reduction of dopamine in the brain. Medications used to treat PD temporarily replace this lost dopamine, but they do not repair the underlying disease. One of the most promising PD therapies to date has been the transplantation of dopamine producing cells into the brain. Unlike current treatments, these therapies may be able to repair the damage caused in PD. In this trial, the investigators will transplant a new stem cell therapy, called the STEM-PD product, into the area of the brain affected in people with PD. These stem cells can develop into many different cell types, including dopamine-producing nerve cells. The investigators will transplant the stem cells using a device that has been previously used for similar transplants in Lund. This is the first time that the STEM-PD product will be given to humans. The trial aims to assess whether the STEM-PD product is safe to use in people with PD. The investigators will also be looking for preliminary signs of efficacy. The trial will recruit participants with PD from the UK and Sweden. Eight participants will undergo the STEM-PD product transplant. Participants will receive a single dose of the STEM-PD product. Participants will attend for 25 visits primarily at their local recruiting hospital. For participants from the UK, some of the imaging will be performed at Invicro (London), and the surgery (including some visits before and after) and some imaging will be performed in Lund. All participants will be followed up for 36 months following surgery