Baseline Lymphopenia Predicts Survival in ICI-Naïve Solid Tumor Patients Receiving Immune Checkpoint Inhibitors: A...

Area of Science:

• Oncology
• Immunology
• Clinical Research

Background:

• Baseline lymphopenia is prevalent in advanced solid tumors.
• Its impact on immune checkpoint inhibitor (ICI) efficacy and safety requires further real-world evidence.
• Absolute lymphocyte count (ALC) may influence treatment outcomes.

Purpose of the Study:

• To assess the association between baseline ALC and clinical outcomes in adults with solid tumors receiving ICIs.
• To evaluate the impact of lymphopenia on overall survival (OS) and adverse events.
• To determine if baseline ALC can serve as a prognostic biomarker for ICI therapy.

Main Methods:

• Retrospective cohort study using TriNetX, including 10,498 ICI-naïve adult patients with solid tumors.
• Propensity score matching (1:1) to compare lymphopenic (ALC < 1.5 × 10^9/L) and non-lymphopenic groups.
• Analysis of overall survival (OS) at multiple time points and risks of healthcare utilization, immune-related adverse events (irAEs), and serious infections.

Main Results:

• Patients with baseline lymphopenia demonstrated consistently worse OS at 6, 12, and 24 months (primary endpoint).
• Lymphopenia was associated with increased healthcare utilization and a higher risk of serious infections at 6 months.
• Rates of clinically coded irAEs were similar between lymphopenic and non-lymphopenic groups, despite worse survival in the lymphopenic cohort.

Conclusions:

• Baseline lymphopenia in patients with solid tumors treated with ICIs is associated with inferior OS and increased early healthcare utilization and infection risk.
• The dissociation between survival and irAE rates suggests ALC may stratify patients by mortality risk and immune activation capacity.
• Baseline ALC is a potential biomarker for predicting ICI therapy prognosis and toxicity, warranting further investigation with competing-risk analyses and immune phenotyping.