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Basic rules to respond to PD-1 blockade cancer immunotherapy
1Medicine, University of California Los Angeles, Los Angeles, California, USA aribas@mednet.ucla.edu.
Abstract:
After 15 years of clinical testing and analyses of biopsies from patients with cancers treated with antibodies blocking the programmed death receptor 1 (PD-1) pathway, several requirements for inducing durable clinical responses have become evident. These basic rules for a response to anti-PD-1 include: (1) the cancer must be immunogenic and differentially recognizable by antitumor T cells, (2) there must be pre-existing antitumor T cells that have the ability to recognize the cancer, which had been activated and had received costimulation, but then are kept in a dysfunctional state due to the reactive cancer expression of the PD-1 ligand 1, (3) on PD-1 blockade, T cells are reinvigorated and produce increased amounts of interferon gamma, which forces the cancer cells into becoming enablers of the antitumor immune response, directly increasing the cancer cell immunogenicity and changing the tumor microenvironment from an unfriendly environment to a friendly environment for the antitumor T cells, and (4) reactivating antitumor T cells before surgery using neoadjuvant anti-PD-1 therapy improves patient outcomes, as the surgery would otherwise take away the majority of antitumor T cells. Collectively, these features are the basis of clinical responses and durable benefit of anti-PD-1 therapy in patients with cancer.
Insights
Anti-PD-1 therapy requires immunogenic cancers with pre-existing T cells. Blocking the PD-1 pathway reinvigorates T cells, enhancing the immune response and improving outcomes for cancer patients.
Area of Science:
- Immunology
- Oncology
- Cancer Research
Background:
- 15 years of clinical data and biopsy analyses from cancer patients treated with anti-PD-1 antibodies inform current understanding.
- Durable clinical responses to anti-PD-1 therapy depend on specific prerequisites for immune system engagement.
Purpose of the Study:
- To elucidate the fundamental requirements for inducing durable clinical responses to anti-PD-1 therapy.
- To outline the mechanisms by which anti-PD-1 blockade enhances antitumor immunity.
Main Methods:
- Analysis of clinical trial data and patient biopsies from cancer patients receiving anti-PD-1 therapy.
- Identification of key immunological factors and cancer cell characteristics associated with treatment response.
Main Results:
- Effective anti-PD-1 therapy necessitates immunogenic cancers recognizable by antitumor T cells.
- Pre-existing, activated antitumor T cells are crucial; they may be suppressed by cancer cell PD-1 ligand expression.
- PD-1 blockade reinvigorates T cells, increasing interferon-gamma production and cancer cell immunogenicity.
- Neoadjuvant anti-PD-1 therapy before surgery improves outcomes by preserving antitumor T cells.
Conclusions:
- The combination of cancer immunogenicity, pre-existing T cell immunity, and PD-1 pathway blockade drives clinical responses.
- Understanding these requirements optimizes the application of anti-PD-1 therapy for durable cancer treatment benefits.
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