Necitumumab Plus Pembrolizumab and Chemotherapy for Untreated Advanced Squamous NSCLC: Phase I/II NEJ048A/NEXUS.

8528 Background: EGFR blockade enhances tumor antigen presentation and may potentiate PD-1 inhibition. This phase I/II study evaluated the safety and efficacy of adding necitumumab to pembrolizumab plus platinum-based chemotherapy in patients with previously untreated advanced squamous non–small cell lung cancer (NSCLC), a population with limited biomarker-driven treatment options. Methods: Patients received necitumumab (400–800 mg on days 1 and 8), pembrolizumab (200 mg on day 1), nab-paclitaxel (100 mg/m² on days 1, 8, and 15), and carboplatin (AUC 5 on day 1) every 3 weeks for four cycles, followed by necitumumab plus pembrolizumab maintenance. Phase I used a standard 3+3 dose-escalation design. Per protocol amendment, patients treated at the recommended dose (RD) in phase I (n = 6) and all phase II patients (n = 6) were pooled for efficacy analyses (n = 12). Tumor assessments were performed every 6 weeks per RECIST v1.1. Primary endpoints were safety and objective response rate (ORR). Data cutoff was September 14, 2025. Results: Twenty-one patients were enrolled, including 15 in phase I (400 mg, n = 6; 600 mg, n = 3; 800 mg, n = 6). One dose-limiting toxicity (DLT) occurred in the 800 mg cohort, which was determined as the RD and maximum tolerated dose (MTD). Among the 12 patients treated at the RD, the ORR was 75.0% (9/12; 95% CI, 42.8–94.5), with partial response in 9 patients, stable disease in 1 patient, and progressive disease in 2 patients. The disease control rate was 83.3%. The 24-week survival rate was 95.2%. Median progression-free survival and overall survival were not reached at the time of analysis. The most frequent adverse events (AEs) in 21 patients were hypomagnesemia (66.7%), acneiform dermatitis (66.7%), neutropenia (61.9%), decreased appetite (52.4%), anemia (52.4%), constipation (47.6%), stomatitis (42.9%), and leukopenia (42.9%). Grade 3 and 4 AEs occurred in 66.7% and 28.6% of patients, respectively, with no grade 5 events. Conclusions: The addition of necitumumab to pembrolizumab and platinum-based chemotherapy demonstrated manageable toxicity and resulted in a high ORR in patients with untreated squamous NSCLC. These findings support the potential activity of EGFR blockade–based immunochemotherapy and warrant further clinical investigation. Clinical trial information: 2031210387.