Discern: A Randomized Pilot Study Comparing Dual Versus Single Immune Checkpoint Blockade Plus Chemotherapy in PD-L1 Negative Advanced Non-Small Cell Lung Cancer

BACKGROUND: Immune checkpoint inhibitors (ICIs) have improved outcomes in metastatic non-small cell lung cancer (NSCLC), but benefit in tumors lacking PD-L1 expression remains limited. Dual checkpoint blockade may enhance antitumor immunity by overcoming an immunologically "cold" tumor microenvironment. Circulating tumor DNA (ctDNA) is an emerging early response biomarker.

PATIENTS AND METHODS: The DISCERN study (UAB 2432) is a single-center, randomized, open-label pilot trial comparing dual immune checkpoint blockade (nivolumab + ipilimumab) plus chemotherapy (Arm A) versus single ICI (pembrolizumab) plus chemotherapy (Arm B) in patients with PD-L1-negative, stage IV NSCLC. The study plans to enroll 24 patients. ctDNA positivity is required at baseline. ctDNA response is evaluated at Cycle 3 Day 1 using Guardant Infinity NGS platform. Primary endpoint is ctDNA molecular response. Secondary endpoints include RECIST-based response rates, progression-free survival (PFS), and overall survival (OS).

CONCLUSION: DISCERN will provide novel insight into the comparative impact of dual versus single ICI regimens in PD-L1-negative NSCLC and the potential role of ctDNA clearance as an early marker of treatment efficacy in this subset of NSCLC.