Replication competent herpes virus strains

A virus strain according to any one of the preceding claims wherein said mutation comprises an alteration to the LAT regions of the virus.

A virus strain according to any one of the preceding claims wherein the ICP0 gene is operably linked to a non-ICP0 promoter.

A virus strain according to any one of the preceding claims which further comprises a mutation in a gene encoding ICP34.5, ICP6, glycoprotein H or thymidine kinase.

A virus strain according to any one of the preceding claims wherein said mutation enhances the expression of VMW65 compared to the otherwise identical virus without said mutation.

A virus strain according to any one of the preceding claims which is incapable of expressing a functional ICP34.5 protein and/or a functional ICP47 protein.

A virus strain according to any one of the preceding claims which further comprises a heterologous gene.

A virus strain according to anyone of the preceding claims which is a strain of herpes simplex virus 1 or 2.

A virus strain according to any one of the preceding claims wherein said permissive cells are tumour cells and non-tumour cells are non-permissive cells.

Use of a virus according to any one of the preceding claims in the manufacture of a medicament for the treatment of cancer.

A pharmaceutical composition comprising, as active ingredient, a virus strain of the invention and a pharmaceutically acceptable carrier or diluent.

An agent for treating cancer comprising a virus strain capable of replicating in permissive cells which virus strain comprises a mutation which results in enhanced ICP0 expression compared to the otherwise identical virus strain without said mutation.