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Cancer Immunotherapy Clinical Trials Continue to Grow Globally, Combination Approaches Outpace Monotherapy Trials

CRI’s latest analysis of the PD1/PDL1 immuno-oncology landscape confirms trends in trial design and patient enrollment, points to robust pipeline of new agents in clinical development

The Cancer Research Institute (CRI), a nonprofit organization dedicated to the discovery and development of powerful immunotherapies for all types of cancer, announced today the publication of its newest analysis of the global landscape of clinical development of drugs that target the PD1/PDL1 immune checkpoint pathway. The report, published today 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 PD1/PDL1 landscape analyses published between 2017 and 2020.

In this most recent analysis, lead author Samik Upadhaya, PhD, assistant director of scientific affairs and member of the Anna-Maria Kellen Clinical Accelerator team at CRI, notes how trends in the global development landscape for PD1/PDL1 agents described in prior CRI reports have largely remained consistent in terms of growth in the number of trials and increased competition for patient enrolment. Key findings of this more recent report include:

  • The number of clinical trials started each year that include a PD1/PDL1-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 FDA-approved PD1/PDL1-blocking monoclonal antibody drugs, nearly a third of active trials are testing other investigational PD1/PDL1-blocking agents, indicating a robust clinical pipeline.
  • The ratio of monotherapy (single-agent) PD1/PDL1-blocking drug trials continues to decrease while the number of combination studies is on the rise, including trials testing PD1/PDL1-blocking immunotherapies in combination with other immunotherapies, targeted therapy, chemotherapies, and radiation.
  • Planned patient enrollment in monotherapy immuno-oncology trials has been falling precipitously, a seven-fold decrease since 2014, while combination trial enrollment projections have seen less than a two-fold drop since 2015.
  • Nearly 300 targets and pathways are being tested in clinical trials in combination with PD1/PDL1-blocking immunotherapy, an increase of 18% compared to the previous report.
  • The administration of PD1/PDL1-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 trials, which together interrogate 28 different targets/mechanisms, including checkpoint pathways other than PD1/PDL1.

The authors also suggest that the number of clinical trials testing PD1/PDL1-targeting immunotherapy drug combinations has begun to outstrip patient demand. The report echoes the U.S. Food and Drug Administration’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 PD1/PDL1-blocking drugs.

This report, titled, “Challenges and opportunities in the PD1/PDL1 inhibitor clinical trial landscape,” 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 IO landscape including clinical development of checkpoint blockade, cancer vaccines, and oncolytic viruses in addition to bispecific antibodies and other immunomodulators.

Reference: Upadhaya S. et al. Challenges and opportunities in the PD1/PDL1 inhibitor clinical trial landscape. Nat. Rev. Drug Discov. 10 Feb 2022. 

About the Cancer Research Institute
The Cancer Research Institute (CRI), established in 1953, is a highly rated U.S. nonprofit organization dedicated exclusively to saving more lives by fueling the discovery and development of powerful immunotherapies for all cancers. Guided by a world-renowned Scientific Advisory Council that includes four Nobel laureates and 27 members of the National Academy of Sciences, CRI has invested $474 million in support of research conducted by immunologists and tumor immunologists at the world’s leading medical centers and universities and has contributed to many of the key scientific advances that demonstrate the potential for immunotherapy to change the face of cancer treatment. To learn more, go to

About the Anna-Maria Kellen Clinical Accelerator
CRI’s clinical program, the Anna-Maria Kellen Clinical Accelerator, is a unique academic-nonprofit-industry collaboration model that serves as an “incubator” that delivers multicenter clinical trials of promising new immunotherapy combinations. CRI’s venture philanthropy fund supports clinical trials within the program, which fosters a collaborative environment that enables scientists to advance their most ambitious research ideas by accelerating studies that one group or company could not do alone. To learn more, go to

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