A More Serious Trial Failure for Gensight ' s Allotopic Expression Implementation

Gensight Biologics uses allotopic expression of a mitochondrial gene, ND4, to attempt to treat the inherited blindness condition Leber hereditary optic neuropathy, in which this gene is mutated and dysfunctional. An altered copy of ND4 is introduced into the cell nucleus, and the protein produced is delivered back to the mitochondria where it is needed for correct function. A fairly standard gene therapy is used to deliver this payload into the retina. Unfortunately, after promising results from earlier trials and technology demonstrations, their late stage trials are failing. It remains to be seen as to why this is the case. Earlier work makes it clear that the technology works in principle. It is possible that intervening too late cannot clear out enough of the damage already done, and that damage makes further decline inevitable, or recovery difficulty. This is a systemic problem for many conditions, given the way in which the structure and enormous cost of clinical trial regulation pushes companies towards the late stage of the disease, rather than earlier, preventative treatment. Equally, it may be that this formulation of the allotopic expression gene therapy isn't achieving a great enough coverage of retinal cells to produce reliable benefits. There are many possible reasons for failure. A phase 3 trial of GenSight Biologics' Leber hereditary optic neuropathy (LHON) gene therapy has missed its primary endpoint. The AAV gene therapy was no better than pl...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs