Antitumor activity of pegylated human interferon β as monotherapy or in combination with immune checkpoint inhibitors via tumor growth inhibition and dendritic cell activation.

Type I interferons (IFN), especially human IFN alpha (IFNα), have been utilized for antitumor therapy for decades. Human interferon beta (IFNβ) is rarely used for cancer treatment, despite advantages over IFNα in biological activities such as tumor growth inhibition and dendritic cell (DC) activation. The utilization of pegylated human IFNβ (PEG-IFNβ), as monotherapy or in combination with immune checkpoint inhibitors (ICIs) was evaluated in this study through in vivo efficacy studies in syngeneic mouse melanoma, non-small cell lung cancer (NSCLC), and colon adenocarcinoma (COAD) models resistant to immune checkpoint inhibitors (ICIs). In vitro comparative study of PEG-IFNβ and pegylated IFNα-2b was performed in terms of tumor growth inhibition against human melanoma, NSCLC and COAD cell lines and activation of human monocyte-derived DCs (MoDCs). Our data demonstrate that the in vivo antitumor effects of PEG-IFNβ are partially attributable to tumor growth-inhibitory effects and DC-activating activities, superior to pegylated IFNα-2b. Our findings suggest that utilizing PEG-IFNβ as an antitumor therapy can enhance the therapeutic effect of ICIs in ICI-resistant tumors by directly inhibiting tumor growth and induction of DC maturation.