Infections during peginterferon/ribavirin therapy are associated with the magnitude of decline in absolute lymphocyte count: results of the IDEAL study.

BACKGROUND: Myelosuppression due to pegylated interferon (peg-IFN) is common during treatment for hepatitis C virus. The relationship between infection risk and decreases in leukocyte lines, however, is not well established. The objective of this analysis was to determine the incidence of and risk factors for infections during peg-IFN/ribavirin (RBV) therapy. METHODS: A total of 3070 treatment-naive, chronic hepatitis C genotype 1-infected patients were treated for up to 48 weeks with peg-IFN alfa-2b 1.5 µg/kg/week or 1 µg/kg/week, or peg-IFN alfa-2a 180 µg/week plus RBV. On-treatment leukocyte counts were obtained every 2-6 weeks. Dose reduction was required for a neutrophil count <0.75 × 10(9) cells/L, and treatment discontinuation was required for a neutrophil count <0.5 × 10(9) cells/L. Granulocyte colony-stimulating factor was prohibited. Data on infections were captured at each study visit and categorized according to MedDRA version 13.0. RESULTS: A total of 581 (19%) patients experienced moderate, severe, or life-threatening infections as assessed by the investigator; 648 (21%) patients had at least 1 neutrophil count <0.75 × 10(9) cells/L, but only 242 (8%) sustained an infection and had a neutrophil count <0.75 × 10(9) cells/L at any time while on treatment. Twelve patients had severe or life-threatening infection and grade 3/4 neutropenia, but only 4 had temporally related infections. In a multivariate logistic regression model, nadir lymphocyte count, history of depression, and female sex, but not nadir neutrophil count, were associated with moderate, severe, or life-threatening infection. CONCLUSIONS: Nadir lymphocyte count, not nadir neutrophil count, was independently associated with moderate, severe, or life-threatening infections in the IDEAL study. Clinicians should be aware of their patients' absolute lymphocyte counts during peg-IFN/RBV therapy; peg-IFN dose reductions may be a consideration in patients with significant lymphocytopenia (<0.5 × 10(9) cells/L).

Genome-wide association study of interferon-related cytopenia in chronic hepatitis C patients.

BACKGROUND & AIMS: Interferon-alfa (IFN)-related cytopenias are common and may be dose-limiting. We performed a genome wide association study on a well-characterized genotype 1 HCV cohort to identify genetic determinants of peginterferon-α (pegIFN)-related thrombocytopenia, neutropenia, and leukopenia. METHODS: 1604/3070 patients in the IDEAL study consented to genetic testing. Trial inclusion criteria included a platelet (Pl) count ≥80×10(9)/L and an absolute neutrophil count (ANC) ≥1500/mm(3). Samples were genotyped using the Illumina Human610-quad BeadChip. The primary analyses focused on the genetic determinants of quantitative change in cell counts (Pl, ANC, lymphocytes, monocytes, eosinophils, and basophils) at week 4 in patients >80% adherent to therapy (n=1294). RESULTS: 6 SNPs on chromosome 20 were positively associated with Pl reduction (top SNP rs965469, p=10(-10)). These tag SNPs are in high linkage disequilibrium with 2 functional variants in the ITPA gene, rs1127354 and rs7270101, that cause ITPase deficiency and protect against ribavirin (RBV)-induced hemolytic anemia (HA). rs1127354 and rs7270101 showed strong independent associations with Pl reduction (p=10(-12), p=10(-7)) and entirely explained the genome-wide significant associations. We believe this is an example of an indirect genetic association due to a reactive thrombocytosis to RBV-induced anemia: Hb decline was inversely correlated with Pl reduction (r=-0.28, p=10(-17)) and Hb change largely attenuated the association between the ITPA variants and Pl reduction in regression models. No common genetic variants were associated with pegIFN-induced neutropenia or leucopenia. CONCLUSIONS: Two ITPA variants were associated with thrombocytopenia; this was largely explained by a thrombocytotic response to RBV-induced HA attenuating IFN-related thrombocytopenia. No genetic determinants of pegIFN-induced neutropenia were identified.

Racial differences in hepatitis C treatment eligibility.

UNLABELLED: Black Americans are disproportionally infected with hepatitis C virus (HCV) and are less likely than whites to respond to treatment with peginterferon (PEG-IFN) plus ribavirin (RBV). The impact of race on HCV treatment eligibility is unknown. We therefore performed a retrospective analysis of a phase 3B multicenter clinical trial conducted at 118 United States community and academic medical centers to evaluate the rates of and reasons for HCV treatment ineligibility according to self-reported race. In all, 4,469 patients were screened, of whom 1,038 (23.2%) were treatment ineligible. Although blacks represented 19% of treated patients, they were more likely not to be treated due to ineligibility and/or failure to complete required evaluations (40.2%) than were nonblack patients (28.5%; P < 0.001). After the exclusion of persons not treated due to undetectable HCV RNA or nongenotype 1 infection, blacks were 65% less likely than nonblacks to be eligible for treatment (28.1% > 17.0%; relative risk, 1.65; 95% confidence interval, 1.46-1.87; P < 0.001). Blacks were more likely to be ineligible due to neutropenia (14% versus 3%, P < 0.001), anemia (7% versus 4%, P = 0.02), elevated glucose (8% versus 3%, P < 0.001), and elevated creatinine (5% versus 1%, P < 0.001). CONCLUSION: Largely due to a higher prevalence of neutropenia and uncontrolled medical conditions, blacks were significantly less likely to be eligible for HCV treatment. Increased access to treatment may be facilitated by less conservative neutrophil requirements and more effective care for chronic diseases, namely, diabetes and renal insufficiency.

Impact of weight-based ribavirin with peginterferon alfa-2b in African Americans with hepatitis C virus genotype 1.

UNLABELLED: WIN-R (Weight-based dosing of pegINterferon alfa-2b and Ribavirin) was a multicenter, randomized, open-label, investigator-initiated trial involving 236 community and academic sites in the United States, comparing response to pegylated interferon (PEG-IFN) alfa-2b plus a flat or weight-based dose of ribavirin (RBV) in treatment-naive patients with chronic hepatitis C and compensated liver disease. Patients were randomized to receive PEG-IFN alfa-2b at 1.5 microg/kg/week plus flat-dose (800 mg/day) or weight-based-dose RBV (800 mg/day for weight <65 kg, 1000 mg/day for 65-85 kg, 1200 mg/day for >85-105 kg, or 1400 mg/day for >105-<125 kg). Sustained virologic response (SVR; undetectable [<125 IU/mL] hepatitis C virus [HCV] RNA at end of follow-up) in patients > or =65 kg was the primary end point. Low SVR rates have been reported among African American individuals, in whom there is a preponderance of HCV genotype 1. This subanalysis of WIN-R was conducted to evaluate the efficacy of weight-based dosing among African American individuals with genotype 1 infection enrolled in the trial. Of 362 African American patients in the primary efficacy analysis, 188 received RBV flat dosing and 174 received weight-based dosing. SVR rates were higher (21% versus 10%; P = 0.0006) and relapse rates were lower (22% versus 30%) in the weight-based-dose group than in the flat-dose group. Safety and rates of drug discontinuation were similar between the 2 groups. CONCLUSION: Weight-based dosing of RBV is more effective than flat dosing in combination with PEG-IFN alfa-2b in African American individuals with HCV genotype 1. Even with weight-based dosing, response rates in African American individuals are lower than reported in other ethnic groups.