Klin Onkol 2026; 39(5): 364-367. DOI: 10.48095/ccko2026364.
Background: Immune checkpoint inhibitors are an integral part of the treatment of a wide range of malignancies, including non-small cell lung cancer (NSCLC). With the expanding indications for immunotherapy in recent years, clinical experience has increased exponentially, encompassing both its therapeutic efficacy and associated adverse events. In an effort to rationalize the use of immunotherapy, considerable attention is currently focused on identification of predictive biomarkers that would allow for more precise selection of patients likely to benefit from this treatment. Case: The authors present a case report of a patient with lung adenocarcinoma characterized by low PD-L1 expression, high tumor mutational burden (37 muts/Mb), and an STK11 mutation. This represents a combination of two predictors of poor response to immunotherapy (low PD-L1 expression and STK11 mutation) along with a high tumor mutational burden, which is conversely considered a predictor of sensitivity to immunotherapy. The patient was treated according to the currently well-established standard of first-line systemic therapy, consisting of pembrolizumab in combination with chemotherapy. This treatment resulted in a durable response, which given its current duration, may be considered sustained with minimal adverse effects. Conclusion: Immune checkpoint inhibitor therapy, as illustrated by this case, may lead to durable responses and prolonged survival even in patients with unfavorable predictive biomarkers. Within the decision-making algorithm prior to initiation of systemic therapy in metastatic NSCLC, it is beneficial to perform a comprehensive and readily available predictive and molecular analysis.