Report Finds Cancer Immunotherapy Clinical Trials Continue to Grow Globally

Combination Approaches Outpace Monotherapy Trials

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The Cancer Research Institute (CRI), a nonprofit organization dedicated to the discovery and development of powerful immunotherapies for all types of cancer, has announced the publication of a new analysis of the global landscape of clinical development of drugs that target the PD-1/PD-L1 immune checkpoint pathway. The report, published by Upadhaya et al in Nature Reviews Drug Discovery, highlights trends in combination therapy clinical trials and planned patient trial enrollment and points to the growing number of clinical trials testing novel bispecific antibodies as a developing trend in the field.

This report is an update to CRI’s previous PD-1/PD-L1 landscape analyses, which were published between 2017 and 2020. In this most recent analysis, the research team noted how trends in the global development landscape for PD-1/PD-L1 agents described in prior CRI reports have largely remained consistent in terms of growth in the number of trials and increased competition for patient enrollment. Key findings of this more recent report include:

  • The number of clinical trials started each year that include a PD-1/PD-L1–targeting agent has continued to increase: currently at 5,683 worldwide, up 278% from the number of trials reported in 2017.
  • While the majority of these trials include at least one of the U.S. Food and Drug Administration (FDA)-approved PD-1/PD-L1–blocking monoclonal antibody drugs, nearly a third of active trials are testing other investigational PD-1/PD-L1–blocking agents, indicating a robust clinical pipeline.
  • The ratio of monotherapy PD-1/PD-L1–blocking drug trials continues to decrease, while the number of combination studies is on the rise, including trials testing PD-1/PD-L1–blocking immunotherapies in combination with other immunotherapies, targeted therapy, chemotherapies, and radiation therapy.
  • Planned patient enrollment in monotherapy immuno-oncology trials has been falling precipitously—a sevenfold decrease since 2014—while combination trial enrollment projections have seen less than a twofold drop since 2015.
  • Nearly 300 targets and pathways are being tested in clinical trials in combination with PD-1/PD-L1–blocking immunotherapy—an increase of 18% compared to the previous report.
  • The administration of PD-1/PD-L1–blocking antibody therapy worldwide is growing intensively, especially in affluent markets that can absorb the high cost of treatment.
  • Bispecific antibodies represent a significant growth area in combination therapy trials, which together interrogate 28 different targets/mechanisms including checkpoint pathways other than PD-1/PD-L1.

The authors also suggested that the number of clinical trials testing PD-1/PD-L1–targeting immunotherapy drug combinations has begun to outstrip patient demand. The report echoes the FDA’s recent call for more collaboration among drugmakers to minimize redundancy, as well as more head-to-head randomized studies comparing the effectiveness of different PD-1/PD-L1–blocking drugs.

To access an interactive dashboard of the PD-1/PD-L1 landscape report, visit the CRI website at

Disclosure: This report was generated in collaboration with IQVIA, a leading global provider of advanced analytics, technology solutions, and clinical research services to the life sciences industry, which provided the authors with access to IQVIA’s proprietary clinical trials database. The report is part of a suite of CRI-owned immuno-oncology landscape analyses that includes reports on cell therapy drug development, COVID-19 impact on oncology trials, and the broader immunotherapy landscape, including clinical development of checkpoint blockade, cancer vaccines, and oncolytic viruses in addition to bispecific antibodies and other immunomodulators. For full disclosures of the report authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.