Future of anti-PD-1/PD-L1 applications: Combinations with other therapeutic regimens

Area of Science:

• Immunology
• Oncology
• Cancer Research

Background:

• Programmed cell death 1 (PD-1)/programmed cell death 1 ligand (PD-L1) blockade is a cornerstone of cancer immunotherapy.
• This therapy aims to enhance T cell responses against tumors by releasing inhibitory signals.
• However, a significant proportion of patients do not respond to PD-1/PD-L1 blockade, necessitating research into resistance mechanisms.

Purpose of the Study:

• To review the mechanisms underlying resistance to PD-1/PD-L1 blockade in cancer therapy.
• To highlight the importance of understanding these resistance mechanisms for improving patient outcomes.
• To discuss potential combinatorial therapeutic strategies to overcome resistance.

Main Methods:

• Literature review of preclinical and clinical data on PD-1/PD-L1 blockade resistance.
• Analysis of cellular and molecular mechanisms contributing to treatment failure.
• Exploration of T cell exclusion, exhaustion, immunosuppressive tumor microenvironment (TME) factors, and tumor-intrinsic factors.

Main Results:

• Resistance to PD-1/PD-L1 blockade is multifactorial, involving T cell exclusion/exhaustion, an immunosuppressive TME, and tumor-intrinsic properties.
• Identifying these resistance mechanisms is key to developing effective combination therapies.
• Current data suggests that combination strategies hold promise for enhancing anti-tumor immunity.

Conclusions:

• Overcoming resistance to PD-1/PD-L1 blockade requires a deep understanding of its underlying cellular and molecular basis.
• Combination therapies targeting resistance mechanisms are essential for improving durable tumor regression.
• Future research should focus on rational design of combination strategies to increase patient response rates to immunotherapy.