The world’s first gene therapy poses little risk of causing cancer, German researchers revealed yesterday.
A genetic study of five patients treated with the new therapy has found little evidence of the virus used for the treatment damaging human genes.
The treatment uses an inactivated adeno-virus to treat a rare inherited metabolic disease, called lipoprotein lipase deficiency.
The inactivation should mean that the virus cannot integrate its DNA into the patient’s cells – but scientists say it can still happen occasionally.
The treatment AAV-LPL S447X was developed in the Netherlands and approved by the European Medicines Agency.
The German researchers studied some 15 million individual genomes from the five patients and concluded that about 1 out of a 1,000 of the virus particles succeeded in getting into the genome.
This happened at random sites, including the mitochondrial genome, they report in Nature Medicine.
Researcher Dr Manfred Schmidt, of the Helmholtz Association of German Research Centres, said: "For the first time, we have thoroughly analyzed in AAV-treated patients whether and where the viral genome integrates. Now we can regard AAV-LPLS447X as safe.
"Those few cases where we have observed integration of viral DNA in muscle cells are barely relevant in view of all the reconstructions and rearrangements that are permanently taking place in our DNA anyway."
He added: "If AAV-LPLS447X stands the test, other gene therapies against more common diseases such as Huntington’s disease or Parkinson’s might also become possible."
A largely random AAV integration profile after LPLD gene therapy. Nature Medicine 2013, DOI: 10.1038/nm.3230
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