Albumin-globulin ratio is a predictive biomarker of antitumour effect of immune checkpoint inhibitors in cancer patients.

Abstract

<h4>Background</h4>Immune checkpoint inhibitors (ICIs) have transformed cancer therapy, yet the heterogeneity of treatment responses underscores the need for reliable prognostic biomarkers. The albumin-to-globulin ratio (AGR), an indicator of systemic inflammation and nutritional status, has emerged as a potential predictor of ICI outcomes. This study aimed to systematically evaluate the prognostic significance of AGR in patients receiving ICIs through a meta-analysis and to validate the findings in a single-centre cohort.<h4>Methods</h4>A systematic literature search was conducted using PubMed, EMBASE, and the Cochrane Library to identify studies published prior to June 6, 2025. The primary endpoints were overall survival (OS), progression-free survival (PFS), and disease control rate (DCR). In addition, a retrospective analysis was performed on a cohort of 74 patients with renal cell carcinoma (RCC) treated with ICIs at our institution to assess the prognostic value of baseline AGR in relation to OS and PFS.<h4>Results</h4>Seven studies encompassing 1,460 patients were included in the meta-analysis. Higher pretreatment AGR was significantly associated with improved OS (HR = 0.44; 95% CI: 0.30-0.66; <i>p</i> < 0.001), extended PFS (HR = 0.61; 95% CI: 0.53-0.71; <i>p</i> < 0.001), and superior DCR (OR = 4.48; 95% CI: 2.58-7.77; <i>p</i> < 0.001). Sensitivity analyses confirmed the robustness of these associations. In our institutional RCC cohort, elevated AGR was independently linked to prolonged OS (<i>p</i> = 0.017) and PFS (<i>p</i> = 0.030), consistent with findings from the pooled data.<h4>Conclusion</h4>AGR is a simple, inexpensive, and non-invasive biomarker with significant prognostic value in patients undergoing ICI therapy. These findings support its potential role in guiding clinical decision-making and optimizing patient selection for immunotherapy.