OncoSil Medical Limited (ASX: OSL) has received results of a study showing that the addition of OncoSil to systemic chemotherapy significantly increases the vascularity of the primary pancreatic tumours and at the same time results in a significant decrease in the size of the tumours.
This is believed to be the first study in humans demonstrating that the poor vascularity of pancreatic cancer tumours can be increased, which may consequently increase the concentration of chemotherapy agents within the tumour and further explains the mode of action of OncoSil.
The prospective, investigator-initiated study recruited patients with unresectable, non-metastatic locally advanced pancreatic cancer (LAPC) undergoing standard FOLFIRINOX chemotherapy plus OncoSil implantation after 2 or 3 cycles of chemotherapy. Patients were assessed using contrast-enhanced harmonic EUS (CH-EUS) after 2 cycles of chemotherapy and at 4 weeks and 12 weeks after OncoSil implantation, in addition to the evaluation of tumor response by CT imaging.
Twenty patients were recruited, with 15 completing 12-week follow-up. After two cycles of chemotherapy and prior to OncoSil implantation, all tumours demonstrated a lower intensity of enhancement relative to surrounding normal pancreatic tissue, suggesting low vascularity (hypovascularity).
At 12 weeks following OncoSil implantation, the local disease control rate was 100%. To date, 5 patients (25%) had their tumours downstaged, with three patients undergoing surgical resection to remove the primary tumour, another patient with surgery pending and one patient having refused surgical treatment. The investigators noted that this was the first clinical study to demonstrate increased vascularity within pancreatic primary tumours.
The study was conducted at the Royal Adelaide Hospital, South Australia
“This is an important study that further explains the mode of action of OncoSil. In addition to delivering a tumourcidal dose of radiation therapy inside the primary pancreatic tumour that leads to significant tumour shrinkage and prolonged local disease control, this study demonstrates that the OncoSil device substantially increases vascularity within the tumour, which may in turn increase the concentration of chemotherapy agents that are widely acknowledged as otherwise being sub-optimal in this devastating disease,” CEO and Managing Director, Nigel Lange, said.