Uncovering prognostic biomarkers through a pharmacovigilance study: the case of RDW

Recent studies highlighted the potential role of Red cell distribution width (RDW) as a prognostic biomarker in oncology. RDW has been associated with systemic inflammation, a key factor in cancer progression. While clinical trials and cohort studies suggest a correlation between RDW alterations and poor prognosis, its specific role in patients undergoing Immune Checkpoint Inhibitor (ICI) therapy remains unclear.

This study aims to explore the potential relationship between RDW alterations and treatment outcomes in patients treated with PD-1 inhibitors using pharmacovigilance data from Eudra Vigilance (EV).

We retrieved Individual Case Safety Reports from EV database, reporting pembrolizumab or nivolumab as suspected drug (January 2015 to March 2025). The Reporting Odds Ratio (ROR) with its 95% of Confidence Interval (95% CI) was computed to assess if drugs of interest have a lower/higher probability of reporting adverse events (AEs) belonging to the System Organ Class "Investigation".

Of 12,289 ICSRs, 6981 (56.8%) involved pembrolizumab and 5308 (43.2%) nivolumab. Most ICSRs referred to male patients aged 18-64. Pembrolizumab showed higher reporting probability of "Platelet count decreased" (ROR 2.41, 95% CI 2.14-2.72), "Neutrophil count decreased" (ROR 1.55, 95% CI 1.34-1.80), "White blood cell count decreased" (ROR 1.50, 95% CI 1.26-1.78), "Blood creatinine increased" (ROR 1.19, 95% CI 1.01-1.42), "C-reactive protein increased" (ROR 1.28, 95% CI 1.07-1.53) compared to nivolumab.

This study provides new insights into the potential prognostic value of RDW in patients treated with ICIs. These results warrant further investigations to determine its utility in monitoring ICI therapy.