Data Support Real-World Benefit of Cemiplimab in Advanced NSCLC Care

First-line cemiplimab (Libtayo) monotherapy produced real-world efficacy and safety outcomes consistent with those reported in the pivotal phase 3 EMPOWER-Lung 1 trial (NCT03088540) among patients with advanced non–small cell lung cancer (NSCLC) and high PD-L1 expression, according to an interim analysis of the prospective observational CEMI-LUNG study (NCT05363319) presented in a poster session at the 2026 European Society for Medical Oncology (ESMO) Congress.^1,2

What were the efficacy outcomes?

At the data cutoff of November 14, 2025, with a median follow-up of 5.91 months among 211 evaluable patients, the median overall survival (OS) was not reached (95% CI, 22.2-not evaluable [NE]), the median progression-free survival (PFS) was 7.6 months (95% CI, 5.5-10.3), and the objective response rate (ORR) was 37.4% (95% CI, 30.9%-44.4%). A complete response occurred in 3.8% of patients along with partial responses in 33.6% and stable disease in 21.3%. When patients with a not-evaluable response were excluded, the ORR was 51.6% (n = 79/153).

“As the primary end point, median [OS] was not reached; almost 55% of patients were alive at 30 months,” said Jesus Corral Jaime, MD, of Hospital Universitario de Jerez in Spain, who presented the findings, in an interview with CancerNetwork®. “These preliminary cemiplimab monotherapy results from the CEMI-LUNG trial that we presented at ESMO provide complementary evidence of benefit from a real-world data population.”

What was the safety profile?

At least 1 immune-mediated adverse event (imAE) occurred in 19.9% of patients (n = 42/211), including grade 3 to 5 events in 4.7% (n = 10); imAEs led to treatment discontinuation in 2.8% (n = 6) of patients and were associated with death in 0.9% (n = 2). The most frequent imAEs were diarrhea (4.3%), hypothyroidism (3.3%), and pneumonitis (3.3%). Pneumonitis was grade 3 to 5 in 1.9% of patients (n = 4).

Treatment-related adverse events (TRAEs) occurred in 34.1% of patients (n = 72/211), with grade 3 to 5 events in 9.5% (n = 20) and serious events in 7.6% (n = 16). TRAEs led to treatment discontinuation in 5.7% (n = 12) of patients and to death in 1.9% (n = 4). Sponsor-identified infusion-related reactions occurred in 0.9% of patients (n = 2).

In an exploratory patient-reported outcomes analysis, numerical improvements were observed in 5 of the 6 scales of the NSCLC Symptom Assessment Questionnaire, with no significant differences from baseline. However, the investigators noted that results should be interpreted with caution given low completion rates.

What was the study design and population?

CEMI-LUNG is an ongoing, European-based, prospective, observational, real-world study described by the investigators as the first prospective observational study to evaluate the real-world effectiveness and safety of cemiplimab monotherapy. The study was conducted across Austria, France, Germany, Italy, and Spain. Patients with locally advanced NSCLC unsuitable for definitive chemoradiation or with metastatic NSCLC who were initiating a cemiplimab-based regimen (350 mg every 3 weeks) as part of routine clinical practice were enrolled, with OS as the primary objective.

The 211-patient monotherapy safety cohort reflected a real-world population; the median age was 72.0 years, 81.5% of patients were 65 years or older, and 13.7% had an ECOG performance status of 2 or higher. At baseline, 84.4% of patients were newly diagnosed, 80.6% had metastatic (stage IVA to IVB) disease, and the median time since initial NSCLC diagnosis was 1.2 months. Additionally, 73.9% had nonsquamous histology, 92.4% had smoking history, and 99.1% had a PD-L1 tumor proportion score of 50% or higher. Among patients with metastatic disease, 22.9% had bone metastases, 11.8% had central nervous system metastases, and 8.2% had liver metastases. The median duration of cemiplimab treatment was 16.0 weeks.

What are the implications?

The investigators concluded that the efficacy outcomes observed in CEMI-LUNG were consistent with those reported in EMPOWER-Lung 1 and that the findings support the benefit of cemiplimab for treating advanced NSCLC in routine clinical practice, including among patients who are often underrepresented in pivotal trials, such as those of advanced age, with an ECOG performance status of 2 or higher, and with predominantly nonsquamous histology. “In my opinion, this study supports the benefit of immunotherapy [alone] with cemiplimab for treating advanced [NSCLC] in real-world practice,” Corral Jaime said. Enrollment in the overall study, which includes a cemiplimab plus chemotherapy cohort, is ongoing.

References

1. Corral Jaime J, Bironzo P, Mascaux C, et al. CEMI-LUNG: a European real-world observational study of cemiplimab monotherapy in advanced non-small cell lung cancer, including effectiveness, safety and patient-reported outcomes. Presented at: European Society for Medical Oncology (ESMO) Congress 2026; October 23-27, 2026; Madrid, Spain. Poster 2580P.
2. Sezer A, Kilickap S, Gümüş M, et al. Cemiplimab monotherapy for first-line treatment of advanced non-small-cell lung cancer with PD-L1 of at least 50%: a multicentre, open-label, global, phase 3, randomised, controlled trial. Lancet. 2021;397(10274):592-604. doi:10.1016/S0140-6736(21)00228-2