Genome and Transcriptome Biomarkers of Response to Immune Checkpoint Inhibitors in Advanced Solid Tumors

Alexandra Pender1, Emma Titmuss2, Erin D Pleasance2

  • 1Department of Medical Oncology, BC Cancer, Vancouver, British Columbia, Canada.

Abstract

Insights

Identifying patients who respond to immune checkpoint inhibitors (ICI) is challenging. Whole genome and transcriptome analysis (WGTA) identified tumor mutation burden and immune cell ratios as key biomarkers for predicting treatment outcomes in advanced cancers.

Area of Science:

  • Oncology
  • Immunotherapy
  • Genomics

Background:

  • Immune checkpoint inhibitors (ICI) have transformed solid tumor treatment, offering durable responses.
  • Predicting patient response to ICI remains a significant challenge, especially in advanced or pretreated cancers.

Purpose of the Study:

  • To identify predictive biomarkers for ICI efficacy in a heterogeneous pan-cancer cohort.
  • To evaluate the utility of whole genome and transcriptome analysis (WGTA) for stratifying patients for immunotherapy.

Main Methods:

  • Retrospective analysis of fresh tumor biopsies from 98 metastatic cancer patients.
  • Utilized whole genome and transcriptome analysis (WGTA) to characterize tumor and immune profiles.
  • Collected baseline characteristics and follow-up data for correlation with treatment outcomes.

Main Results:

  • Tumor mutation burden predicted time to progression (P=0.007).
  • CD8+ T-cell and M1-M2 macrophage ratios were more predictive of overall survival (OS; P=0.0014 and P=0.0012).
  • Combined WGTA markers offered the best patient stratification for OS (P=0.00071); PD-L1 expression did not correlate with clinical benefit.

Conclusions:

  • Interpreting the tumor-immune microenvironment is crucial for predicting ICI efficacy.
  • WGTA enables simultaneous identification of multiple biomarkers for improved patient stratification.
  • Combined biomarkers from WGTA can identify responders in diverse, advanced cancer populations, potentially reducing the need for tumor-specific tests.

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