Increase in platelet count based on inosine triphosphatase genotype during interferon beta plus ribavirin combination therapy
ABSTRACT The inosine triphosphatase (ITPA) genotype is associated with ribavirin-induced anemia and pegylated interferon α (PEG IFN-α)-induced platelet reduction during PEG IFN-α plus ribavirin combination therapy. Natural IFN-β plus ribavirin therapy is associated with increases in platelet counts during treatment. We investigated decreases in platelet counts according to ITPA genotype during natural IFN-β/ribavirin therapy to determine if patients with low platelet counts were eligible for this combination therapy.
A total of 187 patients with chronic hepatitis C received PEG IFN-α/ribavirin or natural IFN-β/ribavirin therapy. Decreases in platelet counts based on ITPA genotype were investigated during treatment through 24 weeks.
Platelet counts decreased during week 1 of PEG IFN-α/ribavirin therapy, but increased during week 2, after which platelet counts decreased gradually. Platelet counts decreased until week 4 of natural IFN-β/ribavirin therapy, after which platelet counts increased. Platelet counts after week 8 were higher relative to pretreatment platelet counts. Patients with the ITPA-CC genotype showed a smaller decrease in platelet counts during natural IFN-β/ribavirin therapy than those with the ITPA-CA/AA genotype; platelet counts after week 8 of this therapy were higher than pretreatment platelet counts, regardless of pretreatment platelet counts. Multivariate logistic regression analyses showed that natural INF-β/ribavirin therapy was the only significant independent predictor for an increase in platelets through week 8.
Natural IFN-β/ribavirin therapy is safe for patients with the ITPA-CC genotype, even if their pretreatment platelet counts are low.
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ABSTRACT: Thrombocytopenia in patients with chronic hepatitis C may represent an obstacle for the initiation of antiviral treatment. The aim of this study was to evaluate factors predictive of successful pegylated interferon (PEG-IFN) α2b and ribavirin (RBV) treatment for patients with thrombocytopenia with no history of splenectomy or partial splenic embolization. One hundred and fifty-one chronic hepatitis C patients (genotype 1: n = 110, genotype 2: n = 41) with TCP (<100 × 10(9) /L) at baseline were enrolled. Pretreatment variables included interleukin 28B (IL28B) genotype (rs8099917) and homoeostasis model assessment of insulin resistance score (HOMA-IR). The kinetics of haemoglobin and platelets according to the inosine triphosphatase (ITPA) genotype (rs1127354) were investigated. Sustained virological response (SVR) was significantly more frequent in hepatitis C virus (HCV) genotype 2 (65.9%) than in genotype 1 (34.5%) patients (P < 0.0001). Multiple logistic regression analysis of HCV genotype 1 extracted IL28B TT genotype [odds ratio (OR) 5.97, P = 0.006] and HOMA-IR <2.5 (OR 7.14, P = 0.0016) as significant independent pretreatment predictors of SVR. The analyses of HCV genotype 2 showed that HOMA-IR was significantly related to SVR, but IL28B genotype was not. Patients with ITPA CC genotype showed a significant haemoglobin reduction and lower degree of platelets decrease than those with ITPA CA/AA genotypes. The most common reason for premature discontinuation of treatment was the development of hepatocellular carcinoma (n = 8, 5.3%). In conclusion, HOMA-IR is a useful predictor of SVR for patients with thrombocytopenia infected with HCV genotype 1 or 2 treated with PEG-IFNα2b and RBV. The inclusion of IL28B, ITPA genotypes and HOMA-IR adds valuable therapeutic information.Journal of Viral Hepatitis 12/2013; 20(12):838-46. DOI:10.1111/jvh.12109 · 3.08 Impact Factor