A recent nationwide cohort study from Norway has provided real-world evidence supporting the use of pembrolizumab, an immune checkpoint inhibitor, in the treatment of non-small cell lung cancer (NSCLC). The study, which analyzed data from over 8,400 patients, found that pembrolizumab, both as a monotherapy and in combination with chemotherapy, significantly improved overall survival (OS) compared to chemotherapy alone.
The retrospective study, leveraging data from the Cancer Registry of Norway (CRN), the Norwegian Patient Registry (NPR), and the Norwegian Prescription Database (NorPD), included all patients diagnosed with NSCLC who initiated non-curative systemic anticancer treatment (SACT) between 2012 and 2021. Patients with EGFR mutations or ALK rearrangements were excluded to focus on the population eligible for pembrolizumab-based therapies.
Pembrolizumab Monotherapy vs. Chemotherapy
Patients receiving pembrolizumab monotherapy as a first-line treatment (1L) between 2017 and 2021 (pembro mono group) were compared to a group receiving platinum-based chemotherapy prior to the availability of 1L ICI (chemo pre-ICI group). The study found a notable survival benefit with pembrolizumab monotherapy.
Pembrolizumab Combination Therapy vs. Chemotherapy
Similarly, patients receiving pembrolizumab in combination with chemotherapy as a first-line treatment (pembro combination group) from 2019 onwards showed improved survival compared to the chemotherapy-only group. This finding aligns with the results of the Keynote-189 trial, which demonstrated the efficacy of pembrolizumab plus chemotherapy in metastatic non-squamous NSCLC.
Comparison to Clinical Trials
The researchers also compared the observed OS in their real-world cohort to the results of the Keynote-024 and Keynote-189 clinical trials. By matching the study population to the trial populations based on key criteria such as ECOG PS, stage, autoimmune disease history, brain metastasis, PD-L1 status, and histology, they found a strong correlation between the real-world outcomes and the clinical trial results. This suggests that the benefits of pembrolizumab observed in clinical trials are generalizable to a broader patient population in a real-world setting.
Data and Methodology
The study utilized comprehensive, individual-level data from multiple national registries, ensuring a high level of completeness and accuracy. The CRN provided detailed information on clinical and demographic characteristics, while the NPR and NorPD contributed data on autoimmune disorders and prescription drugs, respectively. Statistical analyses were performed using Kaplan-Meier methods to estimate overall survival, and raked weights were applied to account for differences in patient characteristics between treatment groups.
Implications for Clinical Practice
The findings of this study reinforce the role of pembrolizumab as a standard-of-care treatment for NSCLC. The real-world evidence confirms the survival benefits observed in clinical trials and supports the use of pembrolizumab, both as monotherapy and in combination with chemotherapy, in eligible patients. This study also highlights the value of leveraging national registries to conduct large-scale, real-world studies that can inform clinical practice and improve patient outcomes.
