Overview

It has long been hypothesised that viruses may have a role in treating cancer. From the mid-1800s, there has been documentation of patients undergoing spontaneous cancer remission following severe infection, and by the start of the 20th century, a temporary complete remission of acute leukaemia was observed in a patient suffering from influenza.1 Over the course of the last century, rodent cancer models have demonstrated tumour regression following virus treatment,1 2 and these promising results led to clinical trials in the 1960s–1970s using ‘anti-cancer’ viruses, which were unfortunately somewhat hampered by their high rate of infectious complications secondary to wild-type virus use.1 2 Over the past three decades, the introduction of genetically engineered viruses that can specifically target cancer cells while leaving normal cells unharmed has opened up an exciting new era of oncolytic virotherapy (the use of viruses to treat cancer), with the advent of a wide spectrum of early phase clinical trials for a range of malignancies.2 3 Importantly, these trials have been safely delivered and well tolerated by patients with cancer with a range of clinical presentation.2 3 More recently, talimogene laherparepvec (an attenuated herpes simplex virus expressing human granulocyte-macrophage colony-stimulating factor for immunostimulation) has demonstrated a major breakthrough in the field, becoming the first oncolytic virus to reach regulatory approval in the …