BackgroundThis study aimed at investigating feasibility of programmed death ligand-1 (PD-L1) testing in plasma samples of advanced NSCLC patients receiving first-line treatment, assessing whether circulating (c)PD-L1 levels were modified by the therapy and whether baseline cPD-L1 levels were associated with patients’ clinical responses and survival outcome.MethodsPeripheral blood samples were collected from 16 healthy volunteers and 56 newly diagnosed NSCLC patients before and at 12th week during the course of first-line therapy. The level of PD-L1 was measured in plasma samples using the human (PD-L1/CD274) ELISA kit (CUSABIO, MD, USA). The Mann Whitney test or Fisher’s test were used for comparisons. Survival analysis was performed using Kaplan Meyer method, providing median and p-value.ResultsBaseline median cPD-L1 was 42.21 pg/ml (range 12.00-143.49) in NSCLC patients and 37.81 pg/ml (range 9.73-90.21) in healthy control cohort (p = 0.78). Median cPD-L1 increased in patients treated with first-line chemotherapy (63.20 pg/ml vs 39.34 pg/ml; p = 0.002), with no changes in patients exposed to non-chemotherapy drugs (42.39 pg/ml vs 50.67 pg/ml; p = 0.398). Time to progression and overall survival were 4.4 vs 6.9 months (p = 0.062) and 8.8 vs 9.3 months (p = 0.216) in cPD-L1 positive vs cPD-L1 negative patients. Baseline cPD-L1 levels increased with the ascending number of metastatic sites, even if the association was not statistically significant (p = 0.063).ConclusionsThis study showed that cPD-L1 testing is feasible, with chemotherapy influencing PD-L1 plasma levels. The possibility of using such test for predicting or monitoring the effect of immunotherapy or combination of chemotherapy and immunotherapy warrant further investigations.
The discovery of mutations in EGFR significantly changed the treatment paradigm of patients with EGFR-mutant non-small cell lung cancer (NSCLC), a particular group of patients with different clinical characteristics and outcome to EGFR-wild-type patients. In these patients, the treatment of choice as first-line therapy is first- or second-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, erlotinib, or afatinib. Inevitably, after the initial response, all patients become refractory to these drugs. The most common mechanism of acquired resistance to EGFR-TKIs is the development of a second mutation in exon 20 of EGFR (T790M). Osimertinib is a third-generation EGFR-TKI designed for overcoming T790M-mediated resistance. Based on the results of efficacy and tolerability of Phase II and Phase III studies, osimertinib has been approved for treatment of advanced EGFRT790M+ mutation NSCLC following progression on a prior EGFR-TKI. Occurrence of acquired resistance to osimertinib represents an urgent need for additional strategies including combination with other agents, such as other targeted therapies or checkpoint inhibitors, or development of new and more potent compounds.
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