Systemic therapy with the infectivity-selective oncolytic adenovirus by targeting mesothelin

Treatment of advanced stage cancers is extremely challenging, and more effective systemic therapy is needed. Oncolytic adenoviruses (OAds) are one of the most promising anti-cancer agents. However, systemic delivery of OAd is challenging due to the low transduction in tumor cells caused by non-selective distribution and sequestration by non-target organs. To overcome this issue, we have previously generated a mesothelin (MSLN)-targeted OAd (AdML-VTIN). Here, we are reporting the potential of MSLN-targeted OAd as an agent for novel systemic treatment using MSLN-expressing lung and pancreatic cancer models. The <i>in vivo</i> biodistribution of AdML-VTIN after intravenous injection showed significantly lower liver sequestration compared to the wild type of OAd (AdML-5WT). By day 7, the intratumoral viral copy number of AdML-VTIN was significantly higher than that of AdML-5WT. For therapeutic efficacy, systemically injected AdML-VTIN exhibited statistically significant anti-tumor effects in both lung and pancreatic cancer xenograft tumor models. In addition, we tested the effect of preexisting immunity using human serum. In a neutralization assay, AdML-VTIN was more resistant to preexisting antibodies, compared to Ad5-WT. Interestingly, the hemagglutination profile of AdML-VTIN was also changed. Our results indicate that MSLN-targeted OAd has great potential to facilitate systemic therapy of advanced cancers.