Shedding light on the molecular determinants of response to anti-PD-1 therapy

Area of Science:

• Oncology
• Immunology
• Genetics

Background:

• Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis show promise for advanced non-small cell lung cancer (NSCLC).
• However, only a subset of patients benefits, and identifying predictive biomarkers remains challenging.
• While PD-L1 expression is a known factor, its accurate assessment is difficult.

Purpose of the Study:

• To investigate the association between tumor mutational burden (TMB) and clinical response to PD-1/PD-L1 inhibitors in NSCLC.
• To explore other molecular factors, including smoking signatures and DNA repair mutations, that may correlate with treatment efficacy.

Main Methods:

• Whole exome sequencing of tumors from two independent NSCLC patient cohorts.
• Analysis of somatic nonsynonymous mutation burden, molecular smoking signatures, DNA repair mutations, and neoantigen burden.
• Correlation of molecular features with clinical outcomes, including objective response rates (ORRs) and progression-free survival (PFS).

Main Results:

• A high somatic nonsynonymous mutation burden was significantly associated with improved durable clinical benefit and higher ORRs.
• Patients with high TMB also experienced longer PFS.
• Clinical efficacy correlated with a molecular smoking signature, specific DNA repair mutations, and a higher burden of neoantigens.

Conclusions:

• Tumor mutational burden is a promising predictive biomarker for response to PD-1/PD-L1 inhibitors in NSCLC.
• Molecular features like smoking signatures and DNA repair mutations may further refine patient selection for immunotherapy.
• These findings support the use of TMB assessment to guide treatment decisions in advanced NSCLC.