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ProSavin, a gene-based treatment for Parkinson's disease

ProSavin is a gene-based treatment for Parkinson's disease, a chronic degenerative neurological condition.

ProSavin uses LentiVector technology to deliver the genes for three enzymes that are required for the synthesis of dopamine. The product is administered locally to the region of the brain called the striatum, where dopamine is needed.
ProSavin converts cells into a replacement dopamine factory within the brain, thus replacing the patient's own lost source of the neurotransmitter in a tonic level analogous to natural dopamine supply in the absence of Parkinson’s disease.

In early-stage Parkinson’s disease, Levodopa ( L-DOPA ) tablets are effective in managing the symptoms. L-DOPA is a chemical building-block which the body converts into dopamine. However, the body progressively loses its ability to convert L-DOPA to dopamine and its effectiveness is reduced with long-term use.
ProSavin is designed to restore local continuous dopamine release to control symptoms without side effects.

In April 2012, Oxford BioMedica announced that a Phase I/II study to assess the safety, efficacy and dose evaluation of ProSavin in patients with mid-to-late-stage Parkinson’s disease successfully met its primary endpoints.
The study evaluated three ascending dose levels of ProSavin ( 1x, 2x and 5x ) in a total of 15 patients.
The primary endpoints were safety and efficacy as measured by improvements in motor function at six months.
ProSavin has demonstrated a long-term safety profile and all 15 patients showed improvements in motor function at the six-month efficacy endpoint relative to baseline.

Pre-clinical studies in the industry standard in vivo model of Parkinson’s disease have shown that, following a single treatment with ProSavin, almost complete recovery of movement behaviour was achieved after five to eight weeks.
The therapeutic effect of ProSavin® was statistically significant after two weeks and was maintained throughout the duration of the pre-clinical studies, with the latest time point being 44 months.

Parkinson’s disease is caused by the degeneration of nerve cells in part of the brain called the substantia nigra. This leads the loss of dopamine, a chemical messenger which plays a vital role in the coordination of body movement.
Loss of dopamine causes nerve cells to fire without normal control, leaving patients less able to control their movement, and is responsible for many of the symptoms of Parkinson's disease such as tremor, muscle stiffness or slow physical movements.
The exact cause of the loss of nerve cells in the brain is unclear; however research indicates that it could be a combination of genetic and environmental factors. ( Xagena )

Source: Oxford Biomedica, 2013