Construction of oncolytic herpes simplex viruses (oHSV) obligate vector and constructs for cancer therapy

A pharmaceutical composition for treating or alleviating cancer in a subject, comprising a pharmaceutically acceptable carrier and a recombinant oncolytic Herpes Simplex Virus type 1 (HSV-1), wherein the recombinant oncolytic HSV-1 has a deletion modification in a wild-type HSV-1 genome and comprises:

• (i) sequences required for expression of all single-copy open reading frames (ORFs) in the genome, comprising the ORFs themselves and regulating sequences necessary for expression of each ORF, wherein the regulating sequences include promoters which are kept intact;
• (ii) only one copy of each of all double-copy genes in the genome;
• (iii) only one copy of duplicated non-coding sequences in the genome;
• and
• (iv) a heterologous nucleic acid sequence encoding IL-12 and an anti-PD-1 agent, wherein the heterologous nucleic acid sequence encoding IL-12 is inserted into the deleted region of the modified HSV-1 genome, and the heterologous nucleic acid sequence encoding the anti-PD-1 agent is inserted between UL3 and UL4 genes in the UL component of the modified HSV-1 genome, and wherein the incorporation of the heterologous nucleic acid sequence does not interfere the expression of the wild-type HSV-1 genes.