Microsatellite instability-high status as a pan-cancer biomarker for immunotherapy efficacy

Thierry Landre1, Gaëtan Des Guetz2

  • 1Assistance Publique Hôpitaux de Paris (AP-HP), Hôpital René Muret, Hôpitaux Universitaires de Paris Seine-St-Denis, Avenue du Dr Schaeffner, 93270, Sevran, France. thierry.landre@aphp.fr.

Abstract

Insights

Microsatellite instability-high (MSI-H) cancers show significant survival benefits with immune checkpoint inhibitors (ICIs). This meta-analysis confirms MSI-H as a key biomarker for predicting ICI response across various cancer types.

Area of Science:

  • Oncology
  • Immunotherapy
  • Cancer Genomics

Background:

  • Microsatellite instability-high (MSI-H) cancers are known to respond exceptionally well to immune checkpoint inhibitors (ICIs).
  • However, comprehensive data on ICI efficacy across different MSI-H cancer types have been limited.
  • This study addresses this gap by analyzing existing clinical trial data.

Purpose of the Study:

  • To systematically review and meta-analyze randomized clinical trials (RCTs) comparing ICIs with chemotherapy in advanced MSI-H/dMMR cancers.
  • To evaluate the efficacy of ICIs in terms of progression-free survival (PFS) and overall survival (OS) across various tumor types.
  • To establish MSI-H as a predictive biomarker for ICI therapy.

Main Methods:

  • A systematic review of RCTs comparing ICIs to chemotherapy in advanced MSI-H/dMMR cancers.
  • Inclusion of 13 RCTs with 1633 MSI-H patients across colorectal, gastric, and endometrial cancers.
  • Analysis of hazard ratios (HRs) for PFS and OS, with subgroup analyses by tumor type and assessment of statistical heterogeneity.

Main Results:

  • Immunotherapy significantly improved PFS and OS in MSI-H patients compared to MSS patients (OS HR=0.35).
  • A 64% reduced risk of progression was observed with immunotherapy (PFS HR=0.36).
  • Significant PFS benefits were noted across colorectal (HR=0.28), gastric (HR=0.43), and endometrial cancers (HR=0.34).

Conclusions:

  • This meta-analysis confirms that MSI-H is a robust predictive biomarker for immune checkpoint inhibitor therapy.
  • The findings support the use of MSI-H status in guiding treatment selection for advanced cancers.
  • There is a clear need for further clinical trials specifically focusing on MSI-H/dMMR populations.