Isolated limb perfusion (ILP) is a treatment for advanced extremity
sarcoma and in-transit
melanoma. Advancing this procedure by investigating the addition of novel agents, such as
cancer-selective oncolytic viruses, may improve both the therapeutic efficacy of ILP and the tumour-targeted delivery of
oncolytic virotherapy. Standard in vitro assays were used to characterise single agent and combinatorial activities of
melphalan, tumour
necrosis factor-alpha (TNF-α) and Lister strain vaccinia virus (GLV-1h68) against BN175 rat
sarcoma cells. An orthotopic model of advanced extremity
sarcoma was used to evaluate survival of animals after ILP with combinations of TNF-α,
melphalan and GLV-1h68. We investigated the efficiency of viral tumour delivery by ILP compared to intravenous
therapy, the locoregional and systemic biodistribution of virus after ILP, and the effect of mode of administration on antibody response. The combination of
melphalan and GLV-1h68 was synergistic in vitro. The addition of virus to standard ILP regimens was well tolerated and demonstrated superior tumour targeting compared to
intravenous administration. Triple
therapy (
melphalan/TNF-α/GLV-1h68) resulted in increased tumour growth delay and enhanced survival compared to other treatment regimens. Live virus was recovered in large amounts from perfused regions, but in smaller amounts from systemic organs. The addition of oncolytic vaccinia virus to existing TNF-α/
melphalan-based ILP strategies results in survival advantage in an immunocompetent rat model of advanced extremity
sarcoma. Virus administered by ILP has superior tumour targeting compared to intravenous delivery. Further evaluation and clinical translation of this approach is warranted.