Anti-PD-L1 checkpoint inhibitor combined with nanocarrier-mediated cisplatin codelivery system for effective treatment of pancreatic cancer.

Immune checkpoint inhibitor-based cancer immunotherapy has shown promise as a potential treatment in the clinic. It has been reported that anti-PD-L1 combined with cisplatin treatment can improve the antitumor effect. However, the therapeutic outcome is limited due to the abundance of tumor stroma in pancreatic cancer (PC), which prevented the penetration of cisplatin and anti-PD-L1 into tumor regions, thus impeding the effectiveness in the treatment of PC. In this study, a nanocarrier-mediated codelivery system of hyaluronidase and cisplatin was constructed, which can degrade the stroma and promote cisplatin and anti-PD-L1 to penetrate the tumor stroma into the deep tumor, so as to suppress PC effectively. When combined the cisplatin nanocarrier system BPEI-SS-Pt/HAase@CaP (BSP/H@CaP) with an immune checkpoint inhibitor to overcome the poor therapeutic outcome of PC, the results indicated that the therapeutic effect of BSP/H@CaP combined with anti-PD-L1 was better than that of BSP/H@CaP and single anti-PD-L1 group. Because the stroma is degrading, a higher amount of BPEI-SS-Pt and anti-PD-L1 can enter the tumor stroma and reach the inner depths of the tumor for immune stimulation, leading to a synergistically augmented chemotherapy and immunotherapy for PC. The above combination therapy is useful for clinical translation to overcome the treatment resistance of matrix-rich PC.