Neutrophil Biomarker Test for Predicting Clinical Benefit From Immunotherapy Based on Flow Cytometry Analysis

Peripheral blood samples will be collected from patients up to 1 month prior to treatment initiation. Ly6Ehi neutrophil populations will be quantified using the NeutroFlow multiparametric flow cytometry assay

The patients clinical benefit (CB) will be defined according to RECIST 1.1 criteria to one of the following categories: complete response (CR), partial response (PR), or stable disease (SD). Baseline Ly6Ehi neutrophil levels will be used as input in a computational predictive model to estimate the likelihood of CB for each patient. The model will be trained and validated with independent patient cohorts, using cross-validation and ROC AUC metrics to assess predictive performance. Sensitivity, specificity, positive predictive value, and negative predictive value will also be calculated. Predictions will be assessed at multiple timepoints: 6, 12, 18, and 24 months post-initiation of anti-PD-(L)1 therapy. Subgroup analyses will include age, sex, cancer type, disease stage, and treatment line.

The clinical benefit rate described in Outcome 2 will be evaluated separately for each cancer indication (e.g., NSCLC, melanoma, HNSCC, RCC, TNBC) at several time points (6, 12, 18 and 24 months post treatment initiation). At least 50 patients per indication will be included to ensure adequate statistical power. ROC AUC values and predictive model performance will be computed for each subgroup. Additional exploratory analyses will examine potential modifiers, including tumor burden, prior therapies, and immune-related biomarkers, to evaluate heterogeneity of response

The clinical benefit rate will be assessed across various anti-PD-(L)1 regimens, including monotherapy and combination protocols. Treatments are classified according to indication and line of therapy:

NSCLC: Monotherapy: Pembrolizumab, Atezolizumab, Cemiplimab. Combination: Pembrolizumab + chemotherapy; Nivolumab + Ipilimumab; Cemiplimab + chemotherapy; Atezolizumab + chemotherapy + Bevacizumab.

Melanoma: Monotherapy: Nivolumab, Pembrolizumab. Combination: Nivolumab + Ipilimumab; Nivolumab + Relatlimab.

HNSCC: Monotherapy: Pembrolizumab, Cemiplimab. Combination: Pembrolizumab + chemotherapy.

RCC: Combination only: Nivolumab + Ipilimumab; Nivolumab + Cabozantinib; Pembrolizumab + Lenvatinib or Axitinib; Avelumab + Axitinib.

TNBC: Combination only: Pembrolizumab + chemotherapy.

In cases where treatment changes occur during follow-up, two scenarios will be considered:

• the patient exits the analysis at the time of treatment change; or
• the new treatment marks a new baseline.

Evaluation of the association between baseline Ly6Ehi neutrophil levels and PD-L1 expression in tumor tissue, measured as Tumor Proportion Score (TPS) and/or Combined Positive Score (CPS), depending on standard of care and assay availability. PD-L1 will be assessed by IHC using validated assays per standard of care. Subgroup analyses will explore correlations within different cancer types and treatment regimens. These analyses will provide insight into whether Ly6Ehi neutrophils complement or enhance PD-L1-based patient stratification.

Exploratory analyses will assess correlations between baseline Ly6Ehi neutrophil levels and other parameters associated with immune checkpoint inhibitor (ICI) response, including Tumor Mutational Burden (TMB), Microsatellite Instability (MSI), Lactate Dehydrogenase (LDH), C-reactive protein (CRP), and ECOG performance status. Multivariate models and correlation analyses will evaluate whether Ly6Ehi neutrophils provide independent predictive value. Subgroup analyses will include cancer type, treatment regimen, and prior therapy exposure. This outcome will help determine the broader immunological and clinical context of Ly6Ehi neutrophil levels