Tumor Mutation Burden Correlates With Efficacy of Chemotherapy/Targeted Therapy in Advanced Non–Small Cell Lung Cancer

Objectives: Accumulating evidence has illustrated greater benefit of immunotherapy in tumors with high tumor mutation burden (TMB), whereas its impact on targeted therapy or chemotherapy is undefined. Herein, we evaluated TMB outside of immuno-oncology in EGFR-mutant patients and EGFR/ALK wild-type cohorts. Materials and Methods: In this retrospective study, we correlated TMB with response rate and progression-free survival (PFS) of patients who received EGFR-TKIs or Pemetrexed/Platinum as first line therapy. TMB was evaluated by targeted next generation sequencing (tNGS). Patients were divided into low(L) / intermediate(I) / high(H) TMB groups by tertiles. Results: In EGFR-mutant cohort, TMB-L patients had an massively improved PFS compared to TMB-I and TMB-H patients (16.4m vs 9.0m vs 7.4m, Log-rank p=0.006) when treated with first-generation EGFR-TKIs. In EGFR/ALK wild-type cohorts who received Pemetrexed/Platinum regimen, the ORR of TMB-L group was statistically superior than that of TMB-I and TMB-H groups (53.8% vs 23% vs 8.3%, Log-rank p=0.037), and patients with low TMB had a numerically, but not significantly prolonged PFS (6.9m vs 4.3m vs 4.6m, Log-rank p=0.22). Conclusion: Our data provide insights into the relevance between TMB and targeted/chemo therapy. Higher nonsynonymous TMB correlates with inferior PFS for first-generation EGFR-TKIs in EGFR-driven patients and worse response to Pemetrexed/Platinum regimen in EGFR/ALK wild-type patients, which has potential clinical implications for cancer treatment but needs corroboration in larger studies