Parkinson’s disease sufferers now have a safe treatment in triple-gene therapy. Called ProSavin, the treatment is to inject three genes from a disabled horse virus into the brain, which will then trigger production of dopamine. Dopamine is the one missing ingredient in Parkinson’s patients, and is necessary for normal movement. The advantage of this new therapy is that it will be a long-term help, whereas current medicines have a five to ten-year efficacy. After a certain number of years, the levodopa medicine cannot sustain its good results.
The research on ProSavin was performed by Oxford-Biomedica in England, and the head of the study is Kyriacos Mitrophanous. Mitrophanous is hopeful for larger trials to be started in the near future. The study, published in The Lancet, has one drawback. This research had no placebo group and the positive findings were in the range that placebos could accomplish. Although it was conducted on twelve human patients, three in the UK and nine in France, there was no group given a placebo to check results against the gene therapy group.
“The ProSavin study was a positive and important first step for a potential gene therapy for Parkinson’s disease,” said Dr. Michael Okun, national medical director at the National Parkinson Foundation. Okun went on to add that he believes the gene therapy will be used for patients in a reasonable amount of time, and will serve as a long-term therapy for proper motor functioning.
What the gene-therapy does is to reprogram cells to make dopamine. The modified virus is injected directly into a specialized region of the brain, where it takes over cells and delivers rehabilitated bits of DNA, prompting defective brain cells to once again start producing dopamine. The cells used in this treatment are different from those in levodopa therapy, and they appear to result in permanent changes of the cells to produce dopamine. The nerve cells involved are changed into ones that produce the necessary dopamine for motor skills.
Parkinson’s disease gene-therapy is considered safe and should be given in trials for humans once it is established as effective, along with blind study groups to examine if it is only a placebo.
The therapy is quite expensive, but researchers are hoping that as more laboratories make the virus, and the process becomes more efficient, that the treatment will be reasonably priced. The amount of the ProSavin to give the patient is also going to be refined to get the best results. Those in the study who received more were better helped with body movement and had less tremors. However, if they were taking their normal medicines as well, there were side effects showing apparent over dosages of dopamine.
It is clear that researchers will want to come up with proper dosing measures of the gene-therapy injections before mass marketing such a product for Parkinson’s disease patients.
French neurosurgeon, Stéphane Palfi, who performed the French stages of the study, said the patients, who were between the ages of 48 and 65, developed better coordination of movement with balance, less muscle twitching and speech improvements, when they were tested after one year. Palfi is confident that with further investigation, ProSavin could be the answer to Parkinson’s patients needs.
Parkinson’s disease triple gene-therapy is safe for those who want to have sustained improved motor functioning. It is hopeful that ProSavin will be accessible to all.
By Lisa M Pickering