Cell therapy for Parkinson's

Parkinson's disease is one of the commonest afflictions caused by damage to the nerve cells of the brain. Patients suffer from muscular tremors and rigidity, and their movements are severely impaired.

These symptoms arise as the result of the degeneration of certain nerve cells which normally release the neural transmitter dopamine - causing an insufficiency of dopamine. To directly combat this decline in dopamine levels, researchers at the company NeuroProgen have developed a new drug on the basis of stem cells which is now being adapted to the regulatory standards of the pharmaceutical industry in partnership with the Fraunhofer Institute for Cell Therapy and Immunology IZI. If all goes well with the scaling-up of the pharmaceutical process, clinical trials of the cell-therapy drug could commence in about twelve months' time - as the first cell therapy employing neural stem cells.

Although current forms of medication can alleviate the symptoms during the first five to ten years following diagnosis, the results of treatment at a later stage often vary unpredictably. This is because the active drug ingredient is not dopamine itself but various precursor molecules. The symptoms can only be relieved if the patient's dopamine-producing cells are capable of taking up the precursor molecules and converting them into dopamine. A normal healthy individual has 800,000 of these cells, whereas a person who has Parkinson's disease will have lost 80 percent of these by the time the first symptoms manifest themselves. The further the disease progresses, the weaker the capacity of the patient's cells to convert the precursor drug.

The new cell therapy works in an entirely different way: "We replace the patient's degenerated cells with fresh human stem cells that have differentiated into nerve cells," explains NeuroProgen chief executive Sigrid Schwarz. "Neurosurgeons can implant these cells in a targeted area of the patient's brain, where they will produce dopamine to compensate for the patient's own insufficiency." The researchers hope that one day a single course of treatment will be all that is needed to cure the disease. The drug manufacturing process is being scaled up by the Fraunhofer team to comply with the quality standards of Good Manufacturing Practice (GMP) required for all pharmaceutical products in their clean-room facilities. "One of the criteria is that the raw materials should not present any risk to the patient," says Gerno Schmiede-knecht, manager in charge of the GMP facilities at the IZI. "We are only allowed to use substances derived from bovine livestock if their origin can be traced back to verified sources in a BSE-free country."