SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 14% of all new cancers and 27% of all cancer deaths. The American Cancer Society estimates that for 2020, about 228, 820 new cases of lung cancer will be diagnosed and 135,720 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers. Of the three main subtypes of NSCLC, 30% are Squamous Cell Carcinomas (SCC), 40% are Adenocarcinomas and 10% are Large Cell Carcinomas. With changes in the cigarette composition and decline in tobacco consumption over the past several decades, Adenocarcinoma now is the most frequent histologic subtype of lung cancer.
Immunotherapy with PD-1/PD-L1 (Programmed Death-1/Programmed Death-Ligand 1) inhibitors, also called Immune Checkpoint Inhibitors (ICIs), has changed the treatment paradigm for patients with advanced NSCLC. In previously treated patients with NSCLC, the Overall Response Rates (ORR) with single agent Immune Checkpoint Inhibitors (ICIs) range from 14-20%, with median Overall Survival (OS) of 10 to 12 months. In those with PD-L1 expression of 50% or more by ImmunoHistoChemical (IHC) analysis, the ORR can reach up to 30% with a median OS of 20 months. However, in patients with negative or weak PD-L1 expression (1%-49% positive tumor cells), who account for approximately two thirds of the NSCLC population, the response rates range from 8-19% with a median OS slightly below 10 months. Even among those with tumors expressing PD-L1 expression of 50% or more, not all patients benefit from Immunotherapy with ICIs. Therefore identifying biomarkers for patients likely to respond to ICI therapy, and predicting resistance is important and relevant in selecting the appropriate patients for treatment with ICIs.
There is growing evidence on the role of inflammation in cancer biology and systemic inflammatory response may have prognostic significance in different cancer types. Inflammatory process in various cancers imparts immunoresistance to ICIs, by activating oncogenic signaling pathways, there by promoting cancer growth and dissemination, with resulting poor outcomes. Derived Neutrophil-to-Lymphocyte ratio (dNLR) and serum Lactate DeHydrogenase (LDH) level have been investigated as potential inflammatory biomarkers in patients with cancer. The dNLR is calculated using a formula dNLR= Absolute Neutrophil Count/(White Blood Count minus Absolute Neutrophil Count). These ratios are simple and easy to calculate from routine blood tests. Both these biomarkers have been correlated with Immune Checkpoint Inhibitor outcomes, in patients with melanoma. In two large studies involving patients with advanced melanoma treated with Ipilimumab and Pembrolizumab, dNLR of 3 or more and LDH of at least 2.5 times Upper Limit of Normal (ULN), reflected a pro-inflammatory status and resulted in poor outcomes.
Based on this important finding in malignant melanoma, Mezquita L and colleagues (JAMA Oncol. 2018;4:351-357) conducted a multicenter, retrospective study involving 466 patients treated with ICIs, to determine whether combining the two factors – pretreatment dNLR and LDH (Lung Immune Prognostic Index-LIPI), was associated with resistance to ICIs in patients with advanced NSCLC. In this study, LIPI was developed on the basis of dNLR (derived Neutrophil-to-Lymphocyte Ratio) of greater than 3 and LDH greater than Upper Limit of Normal (ULN). LIPI was used to stratify patients with NSCLC into 3 groups (Good= 0 factors; Intermediate= 1 of 2 factors, Poor= 2 factors). The authors based on this study concluded that pretreatment LIPI, combining derived Neutrophil-to-Lymphocyte ratio (dNLR) greater than 3 and serum LDH level greater than Upper Limit of Normal, correlated with worse outcomes for Immune Checkpoint Inhibitors (ICIs).
To determine whether LIPI score provides prognostic information for patients with metastatic NSCLC, the authors in this publication performed an exploratory retrospective analysis of the LIPI on pooled clinical trial data from 11 randomized multinational studies (5 ICI trials and 6 targeted therapy trials), and in the final analysis included 3987 patients treated with ICIs, targeted therapy, or cytotoxic chemotherapy, between January 1, 2013, and December 31, 2017. In the 5 ICI trials (N = 2440), 1368 patients received ICIs and 1072 received cytotoxic chemotherapy. In the 6 targeted therapy trials (N = 1547), 53% of EGFR mutant and 47.1% of ALK positive patients received targeted therapy 32.0% of EGFR mutant and 68% of ALK positive patients received cytotoxic chemotherapy. Baseline demographics and disease characteristics were relatively balanced between groups. Lung Immune Prognostic Index (LIPI) scores were calculated based on the dNLR and the LDH level, as mentioned elsewhere in this document.
For patients receiving ICIs, a good LIPI score was associated with longer Overall Survival (OS) compared with a poor LIPI score, with an estimated median survival of 15.6 versus 4.5 months (HR=0.34). A similar prognostic association was observed for patients who received cytotoxic chemotherapy, with patients having a good LIPI score having a longer survival than patients with a poor score, with an estimated median survival of 10.4 versus 5.3 months (HR=0.49). Similar associations were also noted between good LIPI scores and longer Progression Free Survival (PFS). As expected, PD-L1 expression of 1% or more, as well as higher albumin levels was independently associated with improved outcomes.
Among patients with tumors harboring either ALK alterations or EGFR-activating mutations who received targeted therapy, those with a good LIPI score had an estimated median survival of 46.5 months compared with 16.6 months for those with a poor score (HR=0.28). A similar prognostic association was observed in this patient group receiving cytotoxic chemotherapy, with patients having a good LIPI score experiencing a longer survival than patients with a poor score (estimated median survival of 33.4 months versus 17.1 months (HR=0.41). Further, similar associations between LIPI score and PFS were observed. For patients enrolled in these studies, regardless of receiving targeted therapy or cytotoxic chemotherapy, multivariable analysis consistently showed that LIPI score was independently associated with OS and PFS.
It was concluded from this analysis that pretreatment LIPI risk score may be an important prognostic biomarker, irrespective of pharmacologic class of treatment, for patients with metastatic NSCLC. Prognostic Value of the Lung Immune Prognostic Index for Patients Treated for Metastatic Non–Small Cell Lung Cancer. Kazandjian D, Gong Y, Keegan P, et al. JAMA Oncol. 2019;5:1481-1485.