Spectrum and Clinical Activity of PD-1/PD-L1 Inhibitors: Regulatory Approval and Under Development

Purpose of review: The aim of this review is to highlight the clinical development of PD-1 and PD-L1 inhibitors in cancer therapy. We focus on detailing the registration trials that have led to FDA-approved indications of anti-PD-1 and anti-PD-L1 therapies and future strategies.

Recent findings: The number of PD-1/PD-L1 inhibitors approved and in studies continues to grow, in different scenarios. Although the first wave of approvals included advanced cancers, localized disease is under growing interest in recent trials and approvals. Several of these agents are migrating from a monotherapy strategy to combinations (especially with targeted agents and chemotherapy). To date, several studies are being conducted for a better understanding of predictive biomarkers, mechanisms of resistance, optimal treatment duration, and immune-related toxicities. This article summarizes the recent history of modern cancer immunotherapy, provides an overview of novel drug-development considerations, and thus, illustrates the opportunities these new generations of immunotherapies represent.