In recent years, the landscape of non-small cell lung cancer (NSCLC) treatment has undergone a significant transformation, driven primarily by the identification of actionable gene alterations (AGAs) that enable tailored therapeutic approaches. While targeted therapies against well-characterized mutations such as EGFR, ALK, and ROS1 have shown remarkable success, the clinical management of NSCLC patients harboring less common AGAs remains a complex challenge. A groundbreaking retrospective study conducted by researchers at the Samsung Medical Center sheds new light on the efficacy of combining chemotherapy with immune checkpoint inhibitors (ICIs) in this patient population, where targeted options are often limited or inaccessible.
This comprehensive study enrolled 163 NSCLC patients presenting AGAs other than the widely studied EGFR, ALK, and ROS1 mutations who received first-line systemic treatments. The cohort was divided into two groups: those treated with a combination of chemotherapy and ICIs (CT + IO), and those who received chemotherapy (CT) alone. Over an extended median follow-up of 32 months, this extensive dataset allowed for a robust comparison of clinical outcomes, shedding light on response rates, progression-free survival (PFS), time to next treatment (TTNT), and overall survival (OS) amongst these patients.
One of the striking features of the study was the molecular diversity of the patient cohort. The distribution included EGFR exon 20 insertion (E20I) mutations in 28.8% of patients, HER2 mutations (mHER2) in 39.9%, RET fusions in 16.6%, and MET exon 14 skipping mutations (METex14) in 14.7%. These genetic alterations, though less frequently targeted by established therapies, represent a growing frontier for personalized treatment efforts in NSCLC. The researchers meticulously documented clinical outcomes for each subset, unearthing distinct patterns of treatment response.
When analyzing the median PFS, patients treated with the CT + IO regimen showed a promising trend compared to those receiving CT alone, with medians of 8.0 months and 6.4 months, respectively. Although the hazard ratio (HR: 0.71) suggested a 29% reduction in the risk of progression or death with the combined therapy, it narrowly missed conventional statistical significance. Despite this, the findings provide a critical foothold for further exploration of chemoimmunotherapy in genetically diverse NSCLC populations.
Delving deeper into the mutation-specific responses within the CT + IO group revealed even more intriguing data. Patients harboring the METex14 mutation exhibited the most favorable outcomes, with a median PFS of 17.1 months, starkly surpassing other genetic cohorts. This subgroup also demonstrated a notably high level of PD-L1 expression, with almost half of the METex14 patients showing PD-L1 tumor proportion scores (TPS) of 50% or higher, potentially explaining their enhanced responsiveness to ICIs. In comparison, patients with EGFR exon 20 insertions and RET fusions exhibited more modest median PFS intervals of 5.0 and 5.8 months, respectively, while HER2-mutated patients had intermediate outcomes.
This stratification is pivotal because PD-L1 expression, a biomarker indicating immune evasion potential by tumors, remains a critical predictor of ICI efficacy. The study’s survival analysis further underscored this relationship: 24-month overall survival rates increased congruently with PD-L1 expression, reaching 81.5% in patients with the highest expression levels (≥ 50% PD-L1 TPS), compared to 45.4% and 56.3% for those with lower levels. These data highlight that PD-L1 status should be integrated into clinical decision-making frameworks when considering immunotherapy, especially in the context of NSCLC with noncanonical AGAs.
Clinicians often face difficult decisions when molecularly targeted therapies are either unavailable or unapproved for rarer genetic alterations in NSCLC. This study offers a valuable contribution in demonstrating that the combination of chemotherapy and ICIs produces clinical benefit comparable to chemotherapy alone, but with certain patient subsets—such as those with METex14 mutations—experiencing significantly enhanced outcomes. These results invite a reassessment of treatment paradigms, especially considering the expanding armamentarium of immunotherapeutic agents.
Moreover, the findings carry implications for the design of future clinical trials, pushing for stratification based on both genetic alteration and PD-L1 expression. They advocate for inclusion criteria that reflect the genetic heterogeneity seen in real-world clinical settings rather than restricting enrollment to predominant mutations like EGFR and ALK fusions. Such an approach could accelerate the development of tailored regimens, improving survival and quality of life for patients with rarer NSCLC subtypes.
Understanding the interplay between immune mechanisms, genetic drivers, and therapeutic responses remains an ongoing scientific quest. This study enriches our appreciation of the variable immune landscape across different AGAs and underscores the importance of precision oncology. From a mechanistic perspective, mutations such as METex14 may influence tumor microenvironment features, rendering tumors more susceptible to immune checkpoint blockade when combined with cytotoxic chemotherapy.
Despite its retrospective design, the study is strengthened by comprehensive molecular profiling and detailed survival analyses, providing a nuanced view of treatment effects in a challenging patient population. However, prospective validation is essential to confirm these findings and optimize integration strategies for chemotherapy and immunotherapy. The potential synergy between DNA damage induced by chemotherapy and immune activation prompted by ICIs deserves further exploration at the molecular and clinical levels.
In the evolving NSCLC treatment landscape, the Samsung Medical Center’s work illuminates a path forward for patients with actionable gene alterations beyond the EGFR, ALK, and ROS1 spectrum. It paves the way for more individualized therapies tailored by genetic and immunologic tumor signatures, expanding therapeutic horizons beyond the conventional. Importantly, it challenges oncologists to consider immune checkpoint inhibitors in combination regimens when targeted options are constrained.
As this study demonstrates, the chemotherapy plus immune checkpoint inhibitor approach does not merely replicate chemotherapy outcomes but may confer distinct benefits in genetically selected subgroups. The pronounced response and prolonged PFS in METex14 patients signals a need for heightened clinical vigilance in recognizing these mutations and tailoring treatment accordingly. Additionally, PD-L1 expression emerges as a critical biomarker that could refine patient selection, maximizing therapeutic efficacy and minimizing unnecessary toxicity.
This research contributes a vital piece to the complex puzzle of NSCLC treatment optimization in the era of personalized medicine. It calls upon the medical and scientific communities to further investigate the nuances of immune response modulation in genetically diverse tumors and to develop innovative clinical strategies that transcend traditional boundaries. This effort holds promise for transforming the prognosis of many NSCLC patients, enabling longer survival and improved quality of life through precision-guided combinatorial approaches.
In conclusion, integrating chemotherapy with immune checkpoint inhibitors in NSCLC patients harboring actionable gene alterations other than EGFR, ALK, and ROS1 mutations offers a viable and potentially superior treatment paradigm, particularly for those with METex14 mutations and elevated PD-L1 expression. This approach exemplifies the power of precision oncology to harness the immune system alongside cytotoxic therapy, illuminating new avenues in the ongoing battle against lung cancer.
Subject of Research: Combination therapy using chemotherapy and immune checkpoint inhibitors in non-small cell lung cancer patients with actionable gene alterations excluding EGFR, ALK, and ROS1 mutations.
Article Title: Combination of chemotherapy and immune checkpoint inhibitors in non-small cell lung cancer with actionable gene alterations other than EGFR, ALK, and ROS1 mutations: a retrospective observational study
Article References: Shin, J.E., Park, S., Jung, H.A. et al. Combination of chemotherapy and immune checkpoint inhibitors in non-small cell lung cancer with actionable gene alterations other than EGFR, ALK, and ROS1 mutations: a retrospective observational study. BMC Cancer 25, 1616 (2025). https://doi.org/10.1186/s12885-025-14834-1
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