Oncolytic viruses are a promising anti-cancer platform, achieving significant pre-clinical
and clinical milestones in recent years. A full arsenal of selective, safe, and effective viruses has
been developed with some emerging pre-clinical research focusing on optimizing these therapies in
the face of remaining challenges, both in the bloodstream and in the tumour microenvironment.
Herein we discuss the recent progress in pre-clinical virotherapy research to address these challenges,
with special focus on innovative strategies that seek to complement the current strengths of
virotherapy, ensuring an optimal multi-faceted attack on cancer. This review highlights the research
areas that we believe provide the most potential to increase the efficacy of this exciting biotherapy
platform: cell carriers, tumour vascular destruction, microenvironment modulation, combination
therapies, and virus-mediated anti-tumour immune responses.