Treatment response to pegylated interferon based regimen is different between African Americans and Whites, but little comparable data is available comparing Hispanics and African Americans.
We retrospectively evaluated the rate of success in the treatment completion and response to peginterferon alpha-2a or alpha-2b plus ribavirin in 103 (male:female-69:34) hepatitis C virus (HCV)-polymerase chain reaction positive patients that included 68 Hispanic and 35 African Americans.
Patients were treated with peginterferon alpha-2a 180 mcg/wk (n=25) or peginterferon alpha-2b 1.5 mcg/kg/wk (N=78) and ribavirin 1000 to 1200 mg/d for 24 weeks (genotype 2 and 3) or 48 weeks (genotype 1 and 4) based on the genotype of the patient. Treatment was discontinued if the patients failed to have a 2-log drop in viral load after 12 weeks of treatment. Primary aim of the study was to evaluate success in completing a scheduled duration of pegylated interferon and ribavirin treatment in patients with chronic HCV infection and the reasons for discontinuation of the treatment. The secondary aim was to look for the end of treatment virologic response and sustained virologic response. The analysis was conducted by intention-to-treat.
Of the 103 patients included in the study, 50 (48.5%) patients dropped out of the treatment because of side effects of the drug or noncompliance to the treatment protocol or alternate reasons; 44 (42.7%) of them could not continue beyond 12 weeks of therapy. There were no significant differences in the drop out rate between the African American [15 (43%)] and Hispanic [35 (51.5%)] patients (P=0.41). Overall, 41% of the patients completed the scheduled 24 week or 48 week treatment. HCV genotype-1 was the most prevalent genotype in both African Americans and Hispanics (88.6% vs. 75%, P=0.10). Overall end of the treatment response (ETR) was 29.1% (30/103) and sustained virologic response (SVR) was 23.3% (24/103) in this population. No significant differences were noted in the ETR (20% vs. 34%, P=0.14) and the SVR (20% vs. 25%, P=0.57) between the African Americans and Hispanics. When data were analyzed by genotype, overall SVR rates were 14.6% (12/82) in genotype 1 versus 57% (12/21) in genotype 2/3/4 (P<0.0001). Both these ethnic groups had comparable response rates when only patients with genotype-1 were considered 5/31 (16.1%) versus 7/51 (13.7%, P=0.76).
A significant proportion of the African Americans and Hispanics referred for HCV treatment with pegylated interferon dropped out early in the therapy, suggesting possible racial, socioeconomic, and cultural barriers in successful treatment for chronic HCV infection. Overall, both groups had similar poor response rates, well below those reported for White patients. As is true for the general population, patients with nongenotype 1 infection had a significantly better ETR and SVR.
"Our study’s discontinuation rate also falls within the range cumulatively established by studies of other populations of U.S. HCV patients. Estimates of early discontinuation rates include 24% among methadone-maintained patients in California , 36% within a national managed care health plan , and 59% among a non-randomized sample of African Americans and Hispanic patients in New York . Discontinuation rates also vary in U.S. veteran populations. "
[Show abstract][Hide abstract] ABSTRACT: Patients with chronic hepatitis C (HCV) frequently discontinued dual therapy with pegylated interferon alfa (Peg-IFN) plus ribavirin (RBV) before reaching the recommended duration of 48 or 24 weeks for genotypes (G) 1/4 or 2/3, respectively. We quantified rates of discontinuation despite efficacy (non-LOE) versus lack of efficacy (LOE) versus discontinuation for unknown reasons in a national database of United States veterans.
We identified a population-based cohort of U.S. veterans with encounters from 2004 through 2009 who had lab-confirmed HCV infection and initiated therapy with Peg-IFN plus RBV in Veterans Health Administration medical centers. Pharmacy data were used to determine therapy duration, defined as the sum of Peg-IFN days supplied. Patients "discontinued" if they failed to receive at least 44 (G1/4) or 20 weeks (G2/3) of therapy. We classified discontinuations as due to non-LOE, LOE, or unknown reasons using a classification rule based on treatment duration and laboratory confirmed response.
Of 321,238 diagnosed HCV patients during the evaluation period, 9.7% initiated therapy and 6.4% met all other inclusion criteria. 54.9% of patients discontinued early; of these, 41.2% discontinued due to non-LOE reasons, 12.5% discontinued for LOE reasons, and 46.3% discontinued for unknown reasons. Among non-LOE discontinuers, most (60.1%) discontinued in the first 4 weeks of therapy, which constitutes 13.6% of all treated patients.
We observed a high proportion of early discontinuations with dual-therapy regimens in a national cohort of HCV-infected veterans. If this trend persists in the triple-therapy era, then efforts must be undertaken to improve adherence.
BMC Research Notes 04/2014; 7(1):266. DOI:10.1186/1756-0500-7-266
"Additionally, there are significant disparities in access to HCV care for racial/ethnic minorities . Finally, AAs are less likely to respond to anti-HCV therapy than CAs , and have a considerably lower likelihood of receiving liver transplantation . Therefore, there is a need for new prognostic markers to understand the molecular mechanisms of HCC disease progression, especially in the presence of cirrhosis, and to establish the precise biological underpinnings of HCC racial disparities. "
[Show abstract][Hide abstract] ABSTRACT: The incidence and mortality of hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) is higher in African Americans (AA) than other racial/ethnic groups in the U.S., but the reasons for this disparity are unknown. There is an urgent need for the discovery of novel molecular signatures for HCV disease progression to understand the underlying biological basis for this cancer rate disparity to improve the clinical outcome.
We performed differential proteomics with isobaric labeling tags for relative and absolute quantitation (iTRAQ) and MS/MS analysis to identify proteins differentially expressed in cirrhotic (CIR) and HCC as compared to normal tissues of Caucasian American (CA) patients. The raw data were analyzed using the ProteinPilot v3.0. Searches were performed against all known sequences populating the Swiss-Prot, Refseq, and TrEMBL databases. Quality control analyses were accomplished using pairwise correlation plots, boxplots, principal component analysis, and unsupervised hierarchical clustering. Supervised analysis was carried out to identify differentially expressed proteins. Candidates were validated in independent cohorts of CA and AA tissues by qRT-PCR or Western blotting.
A total of 238 unique proteins were identified. Of those, around 15% were differentially expressed between normal, CIR & HCC groups. Target validation demonstrates racially distinct alteration in the expression of certain proteins. For example, the mRNA expression levels of transferrin (TF) were 2 and18-fold higher in CIR and HCC in AA as compared to CA. Similarly; the expression of Apolipoprotein A1 (APOA1) was 7-fold higher in HCC of AA. This increase was mirrored in the protein expression levels. Interestingly, the level of hepatocyte nuclear factor4a (HNF4a) protein was down regulated in AA, whereas repression of transcription is seen more in CA compared to AA. These data suggest that racial disparities in HCC could be a consequence of differential dysregulation of HNF4a transcriptional activity.
This study identifies novel molecular signatures in HCV-induced HCC using iTRAQ-based tissue proteomics. The proteins identified will further enhance a molecular explanation to the biochemical mechanism(s) that may play a role in HCC racial disparities.
Journal of Translational Medicine 10/2013; 11(1):239. DOI:10.1186/1479-5876-11-239 · 3.93 Impact Factor
"Both HCV genotype and HLA allele frequency are distributed geographically. Viral genotype, host genetic background  and HLA class I-  and class II- alleles  are associated with both HCV disease progression and sustained response to therapy . South Africa has diverse ethnic groups, hence a high diversity of HLA genetic background . "
[Show abstract][Hide abstract] ABSTRACT: Background
Host genetics influence the outcome of HCV disease. HCV is also highly mutable and escapes host immunity. HCV genotypes are geographically distributed and HCV subtypes have been shown to have distinct repertoires of HLA-restricted viral epitopes which explains the lack of cross protection across genotypes observed in some studies. Despite this, immune databases and putative epitope vaccines concentrate almost exclusively on HCV genotype 1 class I-epitopes restricted by the HLA-A*02 allele. While both genotype and allele predominate in developed countries, we hypothesise that HCV variation and population genetics will affect the efficacy of proposed epitope vaccines in South Africa. This in silico study investigates HCV viral variability within well-studied epitopes identified in genotype 1 and uses algorithms to predict the immunogenicity of their variants from other less studied genotypes and thus rate the most promising vaccine candidates for the South African population. Six class I- and seven class II- restricted epitope sequences within the core, NS3, NS4B and NS5B regions were compared across the six HCV genotypes using local genotype 5a sequence data together with global data. Common HLA alleles in the South African population are A30:01, A02:01, B58:02, B07:02; DRB1*13:01 and DRB1*03:01. Epitope binding to 13 class I- and 8 class –II alleles were described using web-based prediction servers, Immune Epitope Database, (IEDB) and Propred. Online population coverage tools were used to assess vaccine efficacy.
Despite the homogeneity of genotype 1 and genotype 5 over the epitopes, there was limited promiscuity to local HLA-alleles.Host differences will make a putative vaccine less effective in South Africa. Of the 6 well-characterized class I- epitopes, only 2 class I- epitopes were promiscuous and 3 of the 7 class-II epitopes were better conserved and promiscuous. By fine tuning the putative vaccine using an optimal cocktail of genotype 1 and 5a epitopes and local HLA data, the coverage was raised from 65.85% to 91.87% in South African Blacks.
While in vivo and in vitro studies are needed to confirm immunogenic epitopes, in silico HCV epitope vaccine design which takes into account HCV variation and host allele frequency will maximize population coverage in different ethnic groups.
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