Treatment of chronic hepatitis C in a Canadian Aboriginal population: results from the PRAIRIE study

Pharmacokinetics of a Once Daily Tacrolimus Formulation in First Nations and Caucasian Liver Transplant Recipients

BACKGROUND

Patient ethnicity may influence the pharmacokinetics (PK) of tacrolimus. The Canadian First Nations (FN) constitute a large and increasing segment of the liver transplant population.

OBJECTIVE

To determine whether PK differences exist for a once daily, extended-release formulation of tacrolimus in FN compared to Caucasian (Cauc) liver transplant recipients.

METHODS

Following a 1:1 mg conversion from immediate- to extended-release tacrolimus and achievement of a steady state on the latter formulation, blood samples were drawn at 0, 1, 2, 4, 6, 8 and 24 hours for whole blood tacrolimus levels by commercial immunoassay. CYP3A4 and CYP3A5 allele analyses were performed by polymerase chain reactions.

RESULTS

Nineteen subjects participated in the study (7 FN and 12 Cauc). Unlike Cauc patients, post-conversion Cmin levels did not decrease and were less variable in FN patients. FN patients also had significant shorter Tmax times (1.6±0.2 hours versus 2.8±0.3 hours, p<0.05). Oral clearance, Vd, AUCs, Cmax and Cmin levels were similar in the two cohorts. CYP3A4 genotypes were C/C in both cohorts while the CYP3A5 *1/*3 allele, was present in 2/5 FN and 0/9 Cauc.

CONCLUSIONS

Conversion from immediate- to extended-release tacrolimus results in no significant decrease in Cmin levels, less variable Cmin levels and a shorter time to Tmax in FN compared to Cauc liver transplant recipients.

In the eyes of Indigenous people in Canada: exposing the underlying colonial etiology of hepatitis C and the imperative for trauma-informed care

BACKGROUND

The distribution of hepatitis C (HCV) infection in Canada signals a widening gap between Indigenous and non-Indigenous people. Current evidence demonstrates that the rate of HCV infection among Indigenous people is at least five times higher than the rest of Canada. This analysis provides a reconciliatory response, which exposes the colonial etiology of the HCV gap in Canada and proposes potential anti-colonial approaches to HCV wellness and health care for Indigenous people.

METHODS

This analysis applies Two-Eyed Seeing as a reconciliatory methodology to advance the understanding of HCV burden and identify the key elements of responsive HCV care in the context of Indigenous nations in Canada.

RESULTS

The analysis underlines the colonial distribution of HCV burden in Canada, highlights Indigenous perspectives on HCV infection, hypothesizes a clinical pathway for the underlying colonial etiology of HCV infection, and identifies Indigenous healing as a promising anti-colonial conceptual approach to HCV wellness and health care among Indigenous people.

CONCLUSIONS

In the eyes of Indigenous people, HCV infection is a colonial illness that entails healing as an anti-colonial approach to achieving wellness and gaining health. Future empirical research should elaborate on the colonial HCV pathway hypothesis and inform the development of a framework for HCV healing among Indigenous people in Canada.

Increased mortality among Indigenous persons in a multisite cohort of people living with HIV in Canada

OBJECTIVE

Compare all-cause mortality between Indigenous participants and participants of other ethnicities living with HIV initiating combination antiretroviral therapy (cART) in an interprovincial multi-site cohort.

METHODS

The Canadian Observational Cohort is a collaboration of 8 cohorts of treatment-naïve persons with HIV initiating cART after January 1, 2000. Participants were followed from the cART initiation date until death or last viral load (VL) test date on or before December 31, 2012. Cox proportional hazard models were used to estimate the effect of ethnicity on time until death after adjusting for age, gender, injection drug use, being a man who has sex with men, hepatitis C, province of origin, baseline VL and CD4 count, year of cART initiation and class of antiretroviral medication.

RESULTS

The study sample consisted of 7080 participants (497 Indigenous, 2471 Caucasian, 787 African/Caribbean/Black (ACB), 629 other, and 2696 unknown ethnicity). Most Indigenous persons were from British Columbia (BC) (83%), with smaller numbers from Ontario (13%) and Québec (4%). During the study period, 714 (10%) participants died. The five-year survival probability was lower for Indigenous persons (0.77) than for Caucasian (0.94), ACB (0.98), other ethnicities (0.96) and unknown ethnicities (0.85) (p &lt; 0.0001). In an adjusted proportional hazard model for which missing data were imputed, Indigenous persons were more likely to die than Caucasian participants (hazard ratio = 2.69, p &lt; 0.0001).

CONCLUSION

The mortality rate for Indigenous persons was higher than for other ethnicities and is largely reflective of the BC population. Addressing treatment challenges and identifying HIV- and non-HIV-related causes for mortality among Indigenous persons is required to optimize their clinical management.

Results of interferon-based treatments in Alaska Native and American Indian population with chronic hepatitis C

BACKGROUND

There have been few reports of hepatitis C virus (HCV) treatment results with interferon-based regimens in indigenous populations.

OBJECTIVE

To determine interferon-based treatment outcome among Alaska Native and American Indian (AN/AI) population.

DESIGN

In an outcomes study of 1,379 AN/AI persons with chronic HCV infection from 1995 through 2013, we examined treatment results of 189 persons treated with standard interferon, interferon plus ribavirin, pegylated interferon plus ribavirin and triple therapy with a protease inhibitor. For individuals treated with pegylated interferon and ribavirin, the effect of patient characteristics on response was also examined.

RESULTS

Sustained virologic response (SVR) with standard interferon was 16.7% (3/18) and with standard interferon and ribavirin was 29.7% (11/37). Of 119 persons treated with pegylated interferon and ribavirin, 61 achieved SVR (51.3%), including 10 of 46 with genotype 1 (21.7%), 38 of 51 with genotype 2 (74.5%) and 13 of 22 with genotype 3 (59.1%). By multivariate analysis, SVR in the pegylated interferon group was associated with female sex (p=0.002), estimated duration of infection (p=0.034) and HCV genotype (p<0.0001). There was a high discontinuation rate due to side effects in those treated with pegylated interferon and ribavirin for genotype 1 (52.2%). Seven of 15 genotype 1 patients treated with pegylated interferon, ribavirin and telaprevir or boceprevir achieved SVR (46.7%).

CONCLUSIONS

We had success with pegylated interferon-based treatment of AN/AI people with genotypes 2 and 3. However, there were low SVR and high discontinuation rates for those with genotype 1.

Distribution of Hepatitis C Risk Factors and HCV Treatment Outcomes among Central Canadian Aboriginal

Background. Aboriginal Canadians face many lifestyle risk factors for hepatitis C exposure. Methods. An analysis of Ottawa Hospital Viral Hepatitis Clinic (Ottawa, Canada) patients between January 2000 and August 2013 was performed. HCV infection risk factors and HCV treatment outcomes were assessed. Socioeconomic status markers were based on area-level indicators linked to postal codes using administrative databases. Results. 55 (2.8%) Aboriginal and 1923 (97.2%) non-Aboriginal patients were evaluated. Aboriginals were younger (45.6 versus 49.6 years, p < 0.01). The distribution of gender (63.6% versus 68.3% male), HIV coinfection (9.1% versus 8.1%), advanced fibrosis stage (29.2% versus 28.0%), and SVR (56.3% versus 58.9%) was similar between groups. Aboriginals had a higher number of HCV risk factors, (mean 4.2 versus 3.1, p < 0.001) with an odds ratio of 2.5 (95% confidence interval: 1.4-4.4) for having 4+ risk factors. This was not explained after adjustment for income, social deprivation, and poor housing. Aboriginal status was not related to SVR. Aboriginals interrupted therapy more often due to loss to follow-up, poor adherence, and substance abuse (25.0% versus 4.6%). Conclusion. Aboriginal Canadians have higher levels of HCV risk factors, even when adjusting for socioeconomic markers. Despite facing greater barriers to care, SVR rates were comparable with non-Aboriginals.

Favourable IFNL3 genotypes are associated with spontaneous clearance and are differentially distributed in Aboriginals in Canadian HIV-hepatitis C co-infected individuals

Canadian Aboriginals are reported to clear Hepatitis C (HCV) more frequently. We tested the association of spontaneous clearance and three single nucleotide polymorphisms (SNPs) near the Interferon-lambda 3 (IFNL3) gene (rs12979860, rs8099917, functional variant rs8103142) and compared the SNP frequencies between HIV-HCV co-infected whites and Aboriginals from the Canadian Co-infection Cohort. HCV treatment-naïve individuals with at least two HCV RNA tests were included (n = 538). A spontaneous clearance case was defined as someone with two consecutive HCV RNA-negative tests, at least six months apart. Data were analyzed using Cox proportional hazards adjusted for sex and ethnicity. Advantageous variants and haplotypes were more common in Aboriginals than Caucasians: 57% vs. 46% had the rs12979860 CC genotype, respectively; 58% vs. 48%, rs8103142 TT; 74% vs. 67%, the rs12979860 C allele; and 67% vs. 64% the TCT haplotype with three favourable alleles. The adjusted Hazard Ratios (95% CI) for spontaneous clearance were: rs12979860: 3.80 (2.20, 6.54); rs8099917: 5.14 (2.46, 10.72); and rs8103142: 4.36 (2.49, 7.62). Even after adjusting for rs12979860, Aboriginals and females cleared HCV more often, HR (95% CI) = 1.53 (0.89, 2.61) and 1.42 (0.79, 2.53), respectively. Our results suggest that favourable IFNL3 genotypes are more common among Aboriginals than Caucasians, and may partly explain the higher HCV clearance rates seen among Aboriginals.