Evaluation of the Prognostic Impact of SP263-Evaluated PD-L1 Expression in Patients with Stage III Non-Small Cell Lung Cancer (NSLC) Treated with Radio-Chemotherapy

Background: The PACIFIC study showed that after radio-chemotherapy, patients with NSCLC derived a benefit in PFS and OS when treated with durvalumab. This effect was limited to patients with a PD-L1 expression of >1%, partly because the outcome in the observational control arm was surprisingly favorable. Thus, it could be speculated that a lack of PD-L1 expression confers a favorable outcome for patients with stage III NSCLC. Methods: Clinical data, PD-L1 expression, predictive blood markers, and the outcomes of 99 homogeneously treated patients with stage III NSCLC were retrospectively captured. Statistical analyses using the log rank test were performed. Results: The median OS of patients with an expression of PD-L1 < 1% was 20 months (CI 10.5-29.5) and the median OS of patients with an expression of PD-L1 >= 1% was 28 months (CI 16.5-39.2) (p = 0.734). The median PFS of patients with an expression of PD-L1 < 1% was 9 months (CI 6.3-11.6) and the median PFS of patients with an expression of PD-L1 >= 1% was 12 months (CI 9.8-14.2) (p = 0.112). Conclusions: The assumption that the lack of PD-L1 expression represents a favorable prognostic factor after radio-chemotherapy vs. PD-L1 expression > 1% was not confirmed.