LONDON — Gene therapy specialist Oxford Biomedica plc has developed a technique that simultaneously improves the safety profile of lentivirus vectors and increases their carrying capacity.

Vectors based on lentiviruses can be used to target a wider range of cell types than more commonly used retroviral vectors, because they can transfer genes to non dividing cells. However, safety problems have until now posed major challenges to their use.

Andrew Wood, finance director of Oxford Biomedica, told BioWorld International, "You would expect any viral vector to be disabled so it can't replicate. What we have done is removed nearly all the accessory genes from lentivirus HIV Type 1 that are associated with HIV pathology, whilst retaining its ability to transduce cells. This has two major advantages: the lentivirus is not carrying genes with pathological indications, and it has a greater carrying capacity."

Details of the work are published in the January issue of The Journal of Virology.

Oxford Biomedica, of Oxford, U.K., intends to use the HIV Type 1 vector as the basis of an anti-HIV product. Wood said the company is unlikely to use it in any other indication, "not because it wouldn't be safe, more from the public relations point of view."

Instead, the company intends to apply the technique to another, non primate, lentivirus, which Wood said could be applied very broadly in gene therapy.

Although the HIV vector is prepared, the company is still working on the HIV therapeutic genes. "We would intend to enter clinical trials in 1999," he observed. "Our resources at the moment are focused on two clinical trials we are running in cancer." Wood said the company's strategy is to partner after Phase II.