The Feasibility of Pressurised Intraperitoneal Aerosolised Virotherapy (PIPAV) to Administer Oncolytic Adenoviruses

Capture and inactivation of viral particles from bioaerosols by electrostatic precipitation

Infectious viral particles in bioaerosols generated during laparoscopic surgery place staff and patients at significant risk of infection and contributed to the postponement of countless surgical procedures during the COVID-19 pandemic causing excess deaths. The implementation of devices that inactivate viral particles from bioaerosols aid in preventing nosocomial viral spread. We evaluated whether electrostatic precipitation (EP) is effective in capturing and inactivating aerosolized enveloped and non-enveloped viruses. Using a closed-system model mimicking release of bioaerosols during laparoscopic surgery, known concentrations of each virus were aerosolized, exposed to EP and collected for analysis. We demonstrate that both enveloped and non-enveloped viral particles were efficiently captured and inactivated by EP, which was enhanced by increasing the voltage to 10 kV or using two discharge electrodes together at 8 kV. This study highlights EP as an effective means for capturing and inactivating viral particles in bioaerosols, which may enable continued surgical procedures during future pandemics.

Establishing a New Platform to Investigate the Efficacy of Oncolytic Virotherapy in a Human Ex Vivo Peritoneal Carcinomatosis Model

Oncolytic virotherapy constitutes a promising treatment option for many solid cancers, including peritoneal carcinomatosis (PC), which still represents a terminal stage of many types of tumors. To date, the in vitro efficacy of oncolytic viruses is mostly tested in 2D-cultured tumor cell lines due to the lack of realistic 3D in vitro tumor models. We have investigated the feasibility of virotherapy as a treatment option for PC in a human ex vivo peritoneum co-culture model. Human HT-29 cancer cells stably expressing marker genes GFP and firefly luciferase (GFP/luc) were cultured on human peritoneum and infected with two prototypic oncolytic viruses (GLV-0b347 and MeV-DsRed). Both viral constructs were able to infect HT-29 cells in patient-derived peritoneum with high tumor specificity. Over time, both GFP signal and luciferase activity decreased substantially, thereby indicating successful virus-induced oncolysis. Furthermore, immunohistochemistry stainings showed specific virotherapeutic infections of HT-29 cells and effective tumor cell lysis in infected co-cultures. Thus, the PC model established here provides a clinically relevant screening platform to evaluate the therapeutic efficacy of virotherapeutic compounds and also to investigate, in an autologous setting, the immunostimulatory potential of oncolytic viruses for PC in a unique human model system superior to standard 2D in vitro models.

Current Medical Care Situation of Patients in Germany Undergoing Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC)

Objective: Tailored approaches in gastrointestinal oncology have been more frequently introduced in past years and for patients with peritoneal metastases. This article attempts to overview the current strategies in surgical gastrointestinal oncology, with a focus on gastrointestinal peritoneal metastases. Methods: In 2019, all patients undergoing PIPAC therapy in Germany were retrospectively analyzed regarding morbidity and in-hospital mortality rates. Furthermore, patients with chemotherapy-refractory peritoneal metastases from gastric cancer undergoing PIPAC-therapy at our institution were analyzed. Results: In 2019, 534 patients received PIPAC treatment in german hospitals. The in-hospital mortality rate was 0%. In total, 36 patients suffered from postoperative complications (8%). From April 2016 to September 2021, a total of 44 patients underwent 93 PIPAC applications at our institution. The non-access-rate was 0%. The median PRGS was two (range, 1–4). Eleven patients (44%) showed histologically stable disease, whereas six patients (24%) showed histological regression. Median survival, calculated from the date of the first PIPAC application, was 181 days (range, 43–636 days). Conclusions: PIPAC is a safe and feasible procedure with a low in-hospital morbidity and mortality. Furthermore, PIPAC in the palliative and chemorefractory setting and is an appealing approach for patient management in the future.