Ramesh K. Ramanathan, MD, vice chair of research in the Department of Hematology/Oncology at Mayo Clinic, discusses why pancreatic cancer is resistant to several therapies, as well as the early, preclinical promise observed with immunotherapy.
Pancreatic cancer is very resistant to systemic chemotherapy, Ramanathan explains. Additionally, there are only a handful of drugs with some clinical activity, and response rates that are usually between 20% and 30%. This is possibly due to the fact that there are no commonly detected mutations across patients. Pancreatic cancers are centered by a very dense stroma, which is unlike other tumor types. This can prevent chemotherapy drugs and immune cells from entering tumor cells, leading to a barrier for effective agents, he adds.
Checkpoint inhibitors are being combined with IDO inhibitors and other agents in preclinical studies, which have shown promising results but need longer follow-up in patients. Furthermore, chimeric antigen receptor T cells look promising but the data are very early, Ramanathan says.