Routine blood count fluctuations signal severe immune-related AEs in melanoma
Increased white blood cell (WBC) count and decreased relative lymphocyte count (RLC) are associated with serious adverse events (AEs) such as grade 3/4 or lung/gastrointestinal (GI) immune-related AEs in nivolumab-treated patients with melanoma, a study has found.
Researchers retrospectively examined the medical records of 101 melanoma patients who were treated with nivolumab from several institutes in Japan to test the association between routine blood count parameters (total white blood cell [WBC] count and relative neutrophil, monocyte, lymphocyte and eosinophil counts) during treatment and the occurrence of serious immune-related AEs.
Univariate logistic regression analysis showed that grade 3/4 immune-related AEs correlated with increased total WBC count (p=0.034; cutoff value, 27 percent; area under the curve [AUC], 0.68; odds ratio [OR], 1.58) and decreased RLC (p=0.042; cutoff value, −23 percent; AUC, 0.65; OR, 1.65).
After adjusting for potential confounders, increased WBC count (p=0.014; cutoff value, 59.1 percent; AUC, 0.79; OR, 6.04) and decreased RLC (p=0.012; cutoff value, −32.3 percent; AUC, 0.81; OR, 5.01) similarly emerged as independent factors associated with lung/GI immune-related AEs.
As the analysis was based on the data point at which immune-related AE occurrence was observed, WBC count and RLC are therefore not predictive, but instead a signal of severe immune-related AE occurrence in melanoma patients treated with nivolumab, researchers said.
Known to be resistant to conventional cytotoxic chemotherapy, advanced melanoma has historically lacked effective systemic treatment options. Agents targeting the programmed death-1 (PD-1) receptor and its ligand (PD-L1), such as nivolumab, significantly prolongs survival of metastatic melanoma, although about 10 percent of patients experience severe, even fatal, immune-related AEs. [Ther Adv Med Oncol 2015;7:97–106]