Efficiency and Safety of an Early Dose Adjustment of Ribavirin in Patients Infected With Hepatitis C Underexposed to the Drug and Treated With Peginterferon Ribavirin

Pharmacokinetics-Based Adjusted Versus Standard Dose of Ribavirin Does Not Improve Virologic Response Rates in Chronic Hepatitis C Genotype 4 Patients: A Randomized Controlled Trial

Optimal doses of Ribavirin (RBV) for hepatitis C virus (HCV) treatment are not known. To assess the safety and efficacy of PegIFNalfa-2a in combination with an adjusted (ADJ) RBV dose based on early pharmacokinetics versus a fixed standard (STD) dose of RBV in chronic HCV genotype (GT) 4-naive patients in a randomized trial. One hundred eighty-one patients were randomized. The baseline variables were similar in both arms and females were 50.3% of the patients, 76.5% had minimal-moderate fibrosis (F0-2). Sustained virologic response (SVR) was achieved in 99 (54.7%) subjects. SVR was seen in 50/90 (55.6%) of ADJ dose of RBV and 49/91 (53.9%) of STD dose subjects. Prematurely withdrawal or discontinuation of treatment prematurely in the ADJ RBV arm occurred in 11/90 patients (12.2%) compared with 6/91 subjects (6.6%) in the STD arm (P = 0.214). Similarly, virologic relapse was seen in 14/90 (15.6%) patients of the ADJ arm and 12/91 (13.2%) of the STD arm. Anemia grade 3-4 was seen in 36.7% in ADJ versus 17.6% in STD arm (P = 0.003). Occurrence of rapid virologic response and absences of F4 fibrosis predicted SVR in a univariate analysis. However, age, gender, weight, presence of diabetes, baseline alanine aminotransferase, and vitamin D levels were not significantly different in patients achieving SVR. ADJ higher doses of RBV based on its early pharmacokinetics-based RBV do not improve SVR rates in HCV GT4 treated in combination with peg-IFN alpha-2-a versus STD therapy. Patients on ADJ higher doses of RBV experienced higher rates of anemia and require more erythropoietin without increasing SVR.

DHEA prevents ribavirin-induced anemia via inhibition of glucose-6-phosphate dehydrogenase

Ribavirin has been widely used for antiviral therapy. Unfortunately, ribavirin-induced anemia is often a cause of limiting or interrupting treatment. Our team has observed that dehydroepiandrosterone (DHEA) has a protective effect against in vitro and in vivo ribavirin-induced hemolysis. The aim of this study was to better understand this effect as well as the underlying mechanism(s). DHEA was able to reduce in vitro intraerythrocytic ATP depletion induced by ribavirin. Only 1% of ATP remained after incubation with ribavirin (2 mM) at 37 °C for 24 h vs. 37% if DHEA (200 μM) was added (p < 0.01). DHEA also helped erythrocytes conserve their size, with a shrinkage of only 10% vs 40% at 24 h with ribavirin alone (p < 0.01), and reduced phosphatidylserine exposure at the outer membrane, i.e. 27% vs 40% at 48 h, (p < 0.05). DHEA also inhibits ribavirin-induced hemolysis, i.e. 34% vs 46.5% at 72 h (p < 0.01). DHEA is an inhibitor of glucose-6-phosphate dehydrogenase (G6PD), a key enzyme in the hexose monophosphate shunt connected to the glycolytic pathway which is the only energy supplier of the red blood cell in the form of ATP. We have confirmed this inhibitory effect in the presence of ribavirin. All these observations suggest that ribavirin-induced hemolysis was initiated by ATP depletion, and that the inhibitory effect of DHEA on G6PD was able to rescue enough ATP to limit this hemolysis. This mechanism could be important for improving the therapeutic management of patients treated with ribavirin.