Prognostic Potential of the Prognostic Nutritional Index in Non-Small Cell Lung Cancer Patients Receiving Pembrolizumab Combination Therapy with Carboplatin and Paclitaxel/Nab-Paclitaxel

<b><i>Introduction:</i></b> Pembrolizumab (Pemb) therapy in conjunction with carboplatin and paclitaxel (PTX)/nab-PTX has been efficacious in treating non-small cell lung cancer (NSCLC). However, the response predictors of this combination therapy (Pemb-combination) remain undetermined. We aimed to evaluate whether Glasgow prognostic score (GPS), neutrophil-to-lymphocyte ratio (NLR), body mass index (BMI), platelet-to-lymphocyte ratio (PLR), and prognostic nutritional index (PNI) are potential factors in prognosticating the response to Pemb-combination therapy in advanced NSCLC patients. <b><i>Methods:</i></b> We retrospectively recruited 144 NSCLC patients receiving first-line treatment with Pemb-combination therapy from 13 institutions between December 1, 2018, and December 31, 2020. GPS, NLR, BMI, PLR, and PNI were assessed for their efficacy as prognostic indicators. Cox proportional hazard models and the Kaplan-Meier method were used to compare the progression-free survival (PFS) and overall survival (OS) of the patients. <b><i>Results:</i></b> The treatment exhibited a response rate of 63.1% (95% confidence interval [CI]: 55.0–70.6%). Following Pemb-combination administration, the median PFS and OS were 7.3 (95% CI: 5.3–9.4) and 16.5 (95% CI: 13.9–22.1) months, respectively. Contrary to PNI, NLR, GPS, BMI, and PLR did not display substantially different PFS in univariate analysis. However, multivariate analysis did not identify PNI as an independent prognostic factor for PFS. Furthermore, univariate analysis revealed that GPS, BMI, and PLR exhibited similar values for OS but not NLR and PNI. Patients with PNI ≥45 were predicted to have better OS than those with PNI &lt;45 (OS: 23.4 and 13.9 months, respectively, <i>p</i> = 0.0028). Multivariate analysis did not establish NLR as an independent prognostic factor for OS. <b><i>Conclusion:</i></b> The PNI evidently predicted OS in NSCLC patients treated with Pemb-combination as first-line therapy, thereby validating its efficiency as a prognostic indicator of NSCLC.