LAUSR

e20710 Background: Currently, prognostic markers associated with immunotherapy treatment outcomes in patients with metastatic NSCLC include PDL-1 expression, tumor mutational burden (TBM), and neutrophil to lymphocyte ratio (NLR). In this study we examine the influence of pretreatment changes in weight, BMI, and NLR in 237 patients treated with anti-PD-1/PDL-1 therapy (ICI) at our institution. Methods: This was a retrospective analysis of previously-treated stage IV NSCLC patients who received ICI. Pretreatment (≥ 6 weeks before starting therapy) values of weight, BMI, and NLR were compared to baseline values and NLR was analyzed as continuum and according to standard cutoffs of 3.5 and 5. The same variables were correlated with progression-free survival (PFS) and overall survival (OS) using the Log-Rank test. Results: 237 patients were analyzed: 45% were male, 73% were Caucasian, 72% were former smokers, and 25% were age ≥ 75 years. 148 patients had pretreatment NLR values. Of these, 32% had a ratio < 3.5 and 54% had ratio < 5. 34% had increased NLR at baseline, the majority of which (48/77) had a > 5% increase. 187 patients had pretreatment weight and BMI. Of these, 14% had a pretreatment BMI < 20. 71% had a negative change in BMI and 29% had a > 5% decrease in BMI. 65% had a negative change in weight and 26% had a > 5% decrease in weight. BMI decrease greater than 5% (p = 0.0039), negative weight change (p = 0.0371), and pretreatment NLR > 5 (p = 0.0136) were associated with shorter PFS. Change in NLR trended towards decreased PFS but was not statistically significant (p = 0.07) though only 77 of 237 patients had both values available. There was no statistical PFS difference between patients less than or ≥ 75 years old. Conclusions: The results suggest that decrease in pretreatment BMI and weight along with high baseline NLR are associated with significantly shorter PFS in NSCLC treated with anti-PD-1/PDL-1 therapy. If confirmed, these observations raise the possibility that specific treatment which reverses cancer associated weight loss might enhance effectiveness of immunotherapy.