Optimized gene therapy of Parkinson's disease shows great success

Levodopa is a commonly-used drug to alleviate the symptoms of Parkinson's disease. However, patients taking the drug mostly feel disappointed as the final outcome. When initially taking levodopa, the patient's symptoms in the tremor and balance would be mitigated and controlled. But as time goes on, the effect of drugs will become increasingly worse. They may have to use ultra-high doses of the drug, and some patients may spend several hours in a paralyzed state in almost every day.

Today, Voyager Therapeutics Company located in Cambridge, Massachusetts thought that gene therapy can prolong the efficacy of the drug levodopa. Currently, the company's gene therapy has entered clinical trials with the aid of recombinant proteins such as recombinant mouse proteins.

Parkinson's disease is due to the death of neuron which produces dopamine in brain, resulting in difficulties of patients in athletic ability. People plagued by this disease include the famous boxer Muhammad Ali and actor Michael Fox. Although the reason leading to the death of brain dopamine neuron is still not fully understood by scientists, the reason for the failure of the drug levodopa has been found. Levodopa is the precursor of dopamine. It can be turned into dopamine under the disposal of aromatic L- amino acid decarboxylase (AADC) in the brain. However, in the brain of patients with Parkinson's disease, with the passage of time, AADC levels are decreasing. This results the condition that L-dopa can't be sufficiently converted to dopamine.

The strategy of Voyager wishes to inject adeno-associated virus (AAV) which expresses AADC into the patient's brain through gene therapy, thereby restoring AADC levels in the brains of patients and prolonging the efficacy of levodopa. "We have spent 60 years to study the pharmacology of dopamine," said Steven Paul, CEO of Voyager. "If we can put genes into the right brain tissues at the right time, then there is no reason that we don't succeed."

However, to put the correct gene into the right brain tissue to ensure a sufficient number of expressions is not an easy task. In order to ensure that AADC can express in the correct tissue, Voyager specially designed an injection system which can put the virus carrying AADC gene into the brain. In recent clinical trials, the patients will lie on the MRI machine to accept injection of the virus. Thus, brain surgeon can see the position of the putamen in the brain, thus ensuring the injected virus can cover this important area which needs AADC protein expression. Meanwhile, Voyager Company adds a chemical marker on AADC protein so that the doctor can see the position of proteins which express in the brain after surgery. In ongoing clinical trials, the gene therapy of Voyager has shown a significant effect on some patients.

Dr. Krystof Bankiewicz, one of the co-founders of Voyager said, "We think the failure of previous gene therapy of Parkinson's disease is that the method of gene transfer has not been optimized." Whether the optimized gene therapy of Voyager Company would succeed? We look forward to seeing the results of their clinical trials. Flatebio offers recombinant proteins of good quality like recombinant Cdh4 at competitive prices.