Gene Therapies for PD in clinical trials:
a summary of gene therapy treatments tracked by the Parkinson Pipeline Project Database
Click on to view Parkinson Pipeline Project database record.
The gene coding for the enzyme that converts L-dopa to dopamine (AADC) is inserted into a common, non-pathogenic virus (AAV). The AAV will help to transport the AADC into the brain cells. AAV-hAADC-2, the investigational drug being studied, is injected into the striatum during a surgical procedure.
Currently in Phase I trial / not recruiting.
Sponsors: Ceregene /Genzyme
This approach aims to deliver Neurturin (a nerve growth factor) genes into the nigrostriatal system in an attempt to prevent the degeneration of substantia nigra neurons and the accompanying loss of dopamine. Gene delivery is through an adeno-associated viral (AAV) vector delivery system. Neurturin is a member of the same protein family as GDNF and has similar pharmacological properties.
Currently in Phase II trial / Not recruiting
Phase I results were published in The Lancet Neurology (online April 2, 2008.)
" The procedure was well tolerated. Extensive safety monitoring in all patients revealed no clinically significant adverse events at 1 year.
Several secondary measures of motor function showed improvement at 1 year; for example, a mean improvement in the off -medication motor subscore of the Unified Parkinson’s Disease Rating Scale (UPDRS)of 14 points (SD 8; p=0.000121 [36% mean increase; p=0.000123]) and a mean increase of 2•3 h (2; 25% group mean increase; p=0•0250) in on time without troublesome dyskinesia were seen.
Improvements in several secondary measures were not significant, including the timed walking test in the off condition (p=0•053), the Purdue pegboard test of hand dexterity (p=0•318), the reduction in off time (p=0•105), and the activities of daily living subscore (part II) of the UPDRS (p=0•080).
⁸F-levodopa-uptake PET did not change after treatment with either dose of CERE-120.
The initial data support the safety, tolerability, and potential efficacy of CERE-120 as a possible treatment for PD; however, these results must be viewed as preliminary until data from blinded, controlled clinical trials are available."
Glutamic Acid Decarboxylase (GAD) Gene Therapy
Sponsor: Neurologix / Weill Cornell Medical Center
Treatment involves injecting a small amount of a GAD gene-carrying virus (AAV) into the STN region of the brain to calm it down by turning the excitatory chemical glutamate into the inhibitory brain chemical GABA." The AAV-GAD is slowly delivered surgically through a very fine catheter for 90 minutes.
Currently in Phase II / Recruiting
Phase I Results: “At one year, all 12 patients as a group demonstrated a clinical improvement of 25% in the Unified Parkinson's Disease Rating Scale (UPDRS) compared to baseline.
Nine of the 12 patients showed an average of 37% and five of these patients had substantial improvement of between 40% and 65%.
Clinical improvement also correlated well to metabolic changes in glucose utilization as measured by PET scan. The PET scan data revealed a significant improvement in brain metabolism on the treated side of the brain compared to the untreated side.
No adverse events related to the gene therapy procedure were reported throughout the duration of the 12-month study, or in the subsequent two years since the study formally ended.”
“In Nov. 2007, a 2nd article on the phase I trial was published in Proceedings of the National Academy of Sciences. It reported that, "the previously published safety and tolerability seen in the Phase 1 open label study of Neurologix's Parkinson's disease treatment was also associated with a significant reduction in abnormal network activity in patients receiving the experimental treatment. Moreover, the degree of reduction in this biomarker correlated with the clinical benefit that the treated patients experienced.... Improvements in both clinical symptoms and abnormal brain network activity were seen predominately on the treated side of the brain at six months following treatment. Both the clinical benefit and the metabolic improvement persisted through the 12 months of the study period..."
Gene Therapies for PD in clinical trials: a summary of gene therapy treatments tracked by the Parkinson Pipeline Project Database.
ProSavin Gene Therapy
Sponsor: Oxford Biomedica
ProSavin delivers to the patient's stratium three genes required for synthesis of dopamine. ProSavin is based on a LentiVector system (virus) carrying the genes AADC, TH and CH1. The virus can be delivered precisely into the brain by injection. The genes convert cells that normally do not produce dopamine into cells that do.
Current Phase: I/II in Paris, France / Currently recruiting
Estimated completion date: Jan. 2012
Preclinical Gene Therapy Research
Sponsor: Amsterdam Molecular Therapeutics, (leased from Amgen, Sept. 2008)
The sponsor, a biotech company in the Netherlands, announced on Sept. 18, 2008 that it “obtained a license from Amgen to use their GDNF gene for the development of a gene therapy treatment for Parkinson's disease. The combination of this gene with AMT's proprietary adeno-associated virus (AAV) gene therapy platform could potentially allow the development of an effective, long-term treatment for this PD..”
The GDNF infusion delivery Phase II trial was terminated by Amgen in September 2004. Other delivery systems for GDNF are also in various preclinical stages, such as encapsulated, stem cell and intravenous delivery methods.
Rna Interference (RNAi)
"RNAi is a natural process of gene silencing that occurs in organisms ranging from plants to mammals. By harnessing the natural biological process of RNAi occurring in our cells, the creation of a major new class of medicines, known as RNAi therapeutics, is on the horizon. RNAi therapeutics target the ‘root’ genetic cause of diseases by potently silencing specific messenger RNA, thereby preventing the disease-causing proteins from being made.
Alnylam's Direct RNAi program for PD aims to block production of alpha-synuclein, a protein thought to be the potential cause of PD and one that cannot feasibly be targeted using existing classes of drugs. "
Sponsors: QRxPharma / Un. of Alabama
“During the past decade it was discovered that a gene (DYT-1) and the protein it encodes, called “Torsin”, is critical for normal cellular function in the brain. Torsin is a “chaperone protein” that prevents mutations of proteins that cause neurological disorders such as dystonia and Parkinson’s disease. The core Torsin technology licensed by QRxPharma was developed at the University of Alabama in the US, where scientists demonstrated that a known and already approved drug appears to activate the Torsin system, preventing mutations in other proteins and improving movement disorders in preclinical models of these diseases. Phase II clinical trial is planned for 2008 (sponsor web site)
For more information:
Access the Parkinson Pipeline Project Database at: www.pdpipeline.org
Also see: Gene Therapy Net (news, clinical trials, regulations, guidelines, articles, and more information on gene therapies.)
September 2008 genethearpyreport_sep2008