Homologous recombination deficiency status predicts response to immunotherapy-based treatment in non-small cell lung cancer patients.

Background: Homologous recombination deficiency (HRD) is a biomarker that predicts response to ovarian cancer treatment with poly (ADP-ribose) polymerase (PARP) inhibitors or breast cancer treatment with first-line platinum-based chemotherapy. However, there are few studies on the prognosis of lung cancer patients treated with immune checkpoint inhibitor (ICI) therapy using HRD as a biomarker.

Methods: We studied the relationship between HRD status and the effectiveness of first-line ICI-based therapy in EGFR/ALK wild-type metastatic non-small cell lung cancer patients (NSCLC) patients.

Results: This study included 22 treatment naïve NSCLC patients. The HRD score ranged from -26.37 to 92.34, with an average of 24.57. Based on analysis of the progression-free survival (PFS) data from the included NSCLC patients, threshold traversal was carried out. HRD (+) was defined as an HRD score of 31 or higher. Kaplan-Meier PFS survival analysis showed prolonged median PFS (mPFS) in NSCLC patients with HRD (+) versus HRD (-) (N/A vs. 7.0 ms, log-rank p = 0.029; HR 0.20, 95% CI: 0.04-0.96, likelihood-ratio p = 0.03). In patients with PD-L1 TPS ≥50% and HRD score ≥31 (co-status high), the mPFS was temporarily not reached during the follow-up period. In patients with PD-L1 TPS <1% and HRD score <31, the mPFS was 3 ms. Cox regression analysis showed that the hazard ratio of the co-status was 0.14 (95% CI: 0.04-0.54), which was a good prognostic factor, and the prognostic effect of co-status was better than that of HRD score alone.

Conclusion: The HRD status can be identified as an independent significance in NSCLC patients treated with first-line ICI-based therapy.