The association of nutritional factors on disease control and survival in patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M-HNSCC) treated with anti–PD-1 monoclonal antibody.

6053 Background: Anti-PD-1 mAb therapy is standard of care for systemic treatment for R/M-HNSCC. These patients (pts) also face significant issues with malnutrition. Therefore, we evaluated whether there was any association between outcomes with anti-PD-1 treatment and nutritional markers including BMI, prognostic nutritional index (PNI), and serum albumin. Methods: We collected baseline serum albumin, PNI [(10 × serum albumin (g/dL)) + (0.005 × total lymphocyte count)], BMI, and initial BMI trend (baseline to 3 months), on pts with R/M-HNSCC treated with anti-PD-1 at our institution and evaluated association with disease control (CR/PR/SD vs. PD), PFS, and OS. Baseline BMI was analyzed as a continuous variable and binarily [<18.5 vs. ≥18.5, and median split (23.85)]. Associations of explanatory variables with disease control were evaluated using multivariable logistic regression, reported as odds ratios (ORs) and 95% confidence intervals (CIs) and with PFS and OS using Cox proportional hazards regression, reported as hazard ratios (HRs) and 95% CIs. All analyses were conducted using R version 4.5.2. Results: In our retrospective cohort (n = 124), the median age was 68 and primary sites included oral cavity (39%), larynx (16%), hypopharynx (5%), oropharynx (34%; 64% p16+), and other (6%). 43% of patients received anti-PD-1 for platinum failure and 57% for frontline. On univariate analysis, higher PNI was significantly associated with increased disease control (OR = 1.11; 95% CI: 1.04–1.21; p = 0.007), PFS (HR = 0.96; 95% CI: 0.94-0.98; p < 0.001), and OS (HR = 0.97; 95% CI: 0.95–0.99; p = 0.002). Higher albumin was significantly associated with increased PFS (HR = 0.45; 95% CI: 0.24-0.85; p = 0.014) and OS (HR = 0.25; 95% CI: 0.13-0.48; p < 0.001). Evaluation of baseline characteristics showed platinum failure was significantly associated with worse efficacy and therefore multivariate analysis was conducted, adjusting for platinum failure status. PNI was still significantly associated with increased disease control (OR = 1.09; 95% CI: 1.03–1.18; p = 0.016) and PFS (HR = 0.97; 95% CI: 0.95–0.99; p <0.001). Higher serum albumin was only significantly associated with increased OS (HR = 0.29; 95% CI: 0.14–0.57; p <0.001). Neither baseline nor trend in BMI was associated with efficacy. Conclusions: In our cohort of anti-PD-1 treated R/M-HNSCC pts, higher baseline albumin was associated with increased OS while higher baseline prognostic nutritional index was associated with increased disease control and PFS, including in multivariate analysis. While BMI has been associated with efficacy of anti-PD-1 in other solid tumors, it was not in our cohort. Our data suggests that markers that factor in nutritional and immune status may be more relevant in R/M-HNSCC. Further study is warranted.