Interleukin-6, Hepcidin, and Other Biomarkers in Anemia of Chronic Disease (ACD) and Chemotherapy-Induced Anemia (CIA): Potential Therapeutic Targets.

Anemia in patients with malignancies can be multifactorial including anemia of chronic disease (ACD), also known as anemia of inflammation (AI), and chemotherapy (CT)-induced anemia (CIA) from myelosuppression. Although, exact mechanism for ACD is not known, induction of hepcidin, a key iron-regulatory hormone, by Interleukin (IL)-6 and other pro-inflammatory cytokines with resulting hypoferremia and limitation of iron supply to the bone marrow appear to be major contributors to pathogenesis of anemia. Hepcidin reduces iron levels by inducing degradation of the cellular iron exporter, ferroportin. The objective of this study was to examine the levels of various cytokines/regulators that may play role in ACD.

Chemo-naïve patients with sarcoma scheduled to initiate first-line doxorubicin-based chemotherapy had blood samples drawn at baseline, and following chemotherapy (post cycles1, 3 and 6) for analysis of pro-inflammatory cytokines/other biomarkers of anemia. Serum samples were analyzed for IL-1β, IL-6, TNF-α, Hepcidin, hemojuvelin, ferroportin, soluble transferrin receptor (sTFR), and C-reactive protein (CRP) using ELISA techniques (R&D Diagnostics, Uscn Life Science Inc, or Abnova). Correlations between these biomarkers and Hgb levels at baseline and during the study period were calculated by linear regression analysis (SAS 9.2).

Of the 49 patients enrolled on to the clinical trial, there were 26 (53%) women and 23 (47%) men, with median age 45 years (range 19–65 years). Twenty-five percent of the patients had Hgb less than 12g/dL (range, 8.9–15.9 g/dL) prior to CT. At baseline, 50% of the pts had hypoferremia with low serum iron and transferrin saturation <20%. Baseline serum levels of IL-6 (r= −0.73, p<0.0001), hepcidin (r= −0.46, p=0.005), CRP (r= −0.46, p=0.003), sTFR (r= −0.32, p=0.064) inversely correlated with hemoglobin levels prior to CT, supporting their role in ACD. During CT (median 4, range; 1–6 cycles), Hgb declined in all pts with 55% requiring PRBC transfusions (77% of pts starting with baseline Hgb < 12 g/dL vs 47% of pts with baseline Hgb > 12 g/dL). Interestingly, as shown below, Hepcidin, IL-6, and sTFR all significantly negatively correlated with Hgb levels during CT.

No significant correlation was found for IL-1β, TNF-α, ferroportin, or hemojuvelin levels with Hgb.

IL-6 and Hepcidin pathway appears to play an important role in anemia in cancer patients before and during CT. Treatment with novel agents targeting this pathway may provide effective strategies for prevention and treatment of ACD and CIA.

Vadhan-Raj:JNJ: Research Funding.