Renal function in HIV/HBV co-infected and HBV mono-infected patients on a long-term treatment with tenofovir in real life setting

Renal outcomes in adults with HBV, HIV and HBV/HIV coinfection after 3 years of antiviral therapy in urban Tanzania

BACKGROUND

An enhanced understanding of renal outcomes in persons with chronic HBV, HIV, and HBV/HIV coinfection is needed to mitigate chronic kidney disease in regions where HBV and HIV are endemic.

OBJECTIVES

To investigate changes in estimated glomerular filtration rate (eGFR) in adults with HBV, HIV or HBV/HIV enrolled in a 3 year prospective cohort study of liver outcomes in Dar es Salaam, Tanzania and initiated on antiviral therapy.

METHODS

We compared eGFR between and within groups over time using mixed-effects models.

RESULTS

Four hundred and ninety-nine participants were included in the analysis (HBV: 164; HIV: 271; HBV/HIV: 64). Mean baseline eGFRs were 106.88, 106.03 and 107.18 mL/min/1.73 m2, respectively. From baseline to Year 3, mean eGFR declined by 4.3 mL/min/1.73 m2 (95% CI -9.3 to 0.7) and 3.7 (-7.8 to 0.5) in participants with HBV and HIV, respectively, and increased by 5.1 (-4.7 to 14.9) in those with HBV/HIV. In multivariable models, participants with HBV had lower eGFRs compared with those with HIV or HBV/HIV and, after adjusting for HBV DNA level and hepatitis B e antigen (HBeAg) status, significantly lower eGFRs than those with HBV/HIV at all follow-up visits.

CONCLUSIONS

In this Tanzanian cohort, coinfection with HBV/HIV did not appear to exacerbate renal dysfunction compared with those with either infection alone. Although overall changes in eGFR were small, persons with HBV experienced lower eGFRs throughout follow-up despite their younger age and similar baseline values. Longer-term studies are needed to evaluate continuing changes in eGFR and contributions from infection duration and other comorbidities.

Brief Report: Relationship Between ABCC4 SNPs and Hepatitis B Virus Suppression During Tenofovir-Containing Antiretroviral Therapy in Patients With HIV/HBV Coinfection

BACKGROUND

Incomplete hepatitis B virus (HBV) suppression during antiretroviral therapy (ART) in HIV and HBV coinfected patients is common, but underlying factors are not fully elucidated. We hypothesize that genetic factors that influence nucleoside analog pharmacokinetics will affect HBV treatment response.

METHODS

HIV/HBV coinfected patients on tenofovir disoproxil fumarate/lamivudine (TDF/3TC)-containing ART were enrolled. Selected ABCC4 single nucleotide polymorphisms (SNPs) with known effects on nucleoside pharmacokinetics were genotyped using TaqMan assays. Relationship between ABCC4 SNPs and unsuppressed HBV DNA (HBV DNA ≥20 IU/mL) were examined.

RESULTS

Of the 50 participants on TDF/3TC-containing ART for a median (range) of 1.5 (1-7.4) years, 20 (40%) had unsuppressed HBV DNA. Participants with unsuppressed compared with those with suppressed HBV DNA were more likely to have negative HBe antibody, lower body mass index, and lower CD4 count at enrollment. Carriers of ABCC4 rs11568695 (G3724A) variant allele were more likely than noncarriers to have unsuppressed HBV (61.1% vs. 29.0%, P = 0.038). Among 36 patients with suppressed HIV RNA (presumed good ART adherence), ABCC4 rs11568695 variant carriers were more likely than noncarriers to have unsuppressed HBV (58.8% vs. 20.0% P = 0.021). Logistic regression analysis that included genetic and nongenetic factors identified ABCC4 rs11568695 variant allele, body mass index, and male sex as predictors of unsuppressed HBV DNA.

CONCLUSIONS

We identified a novel association between ABCC4 rs11568695 SNP and poor HBV treatment response. If confirmed in further studies, ABCC4 genotyping could be used to identify individuals who may need intensified HBV therapy.

Long-term outcomes with oral therapy in liver transplant recipients with hepatitis B

BACKGROUND

The long-term impact of oral hepatitis B antiviral therapy in liver transplant (LT) recipients is currently underexplored. The objective of this study was to evaluate how oral antiviral agents impact long-term renal function in this population.

METHODS

We studied 79 patients who received a LT for hepatitis B and were placed on all-oral antiviral therapy after withdrawing from hepatitis B immune globulin therapy at the University of California, Los Angeles. Laboratory data were obtained through a retrospective chart review. Univariate analysis and two-sided t tests were performed.

RESULTS

The mean (±SD [standard deviation]) age at the time of LT was 65.4 (± 8.2) years. The overall mean (±SD) follow-up from LT was 6.5 (±3.3) years. 22.8% (18/79) of recipients on all-oral therapy had worsening of their chronic kidney disease stage, and 17.7% (14/79) had an increase in creatinine of at least 0.3 mg/dL. There were no significant changes in creatinine and GFR in patients while on tenofovir alafenamide. Patient survival was decreased for recipients who developed detectable HBsAg.

CONCLUSION

Tenofovir alafenamide appears to have less of an impact on renal function in LT recipients than other antiviral agents. HBV recurrence after transplant is associated with decreased patient survival and remains an important issue to address for LT recipients on oral antiviral therapy.

Duration of Pediatric Clinical Trials Submitted to the US Food and Drug Administration

Importance

The increasing prevalence of pediatric chronic disease has resulted in increased exposure to long-term drug therapy in children. The duration of recently completed drug trials that support approval for drug therapy in children with chronic diseases has not been systematically evaluated. Such information is a vital first step in forming safety pharmacovigilance strategies for drugs used for long-term therapy in children.

Objective

To characterize the duration of clinical trials submitted to the US Food and Drug Administration (FDA) for pediatric drug approvals, with a focus on drugs used for long-term therapy.

Design and Setting

A review was performed of all safety and efficacy clinical trials conducted under the Best Pharmaceuticals for Children Act or the Pediatric Research Equity Act and submitted to the FDA from September 1, 2007, to December 31, 2014, to support the approval of drugs frequently used for long-term therapy in children. Statistical analysis was performed from July 1, 2015, to December 31, 2017.

Main Outcomes and Measures

Maximum duration of trials submitted to support FDA approval of drugs for children.

Results

A total of 306 trials supporting 86 drugs intended for long-term use in children were eligible for the primary analysis. The drugs most commonly evaluated were for treatment of neurologic (25 [29%]), pulmonary (16 [19%]), and anti-infective (14 [16%]) indications. The median maximum trial duration by drug was 44 weeks (minimum, 1.1 week; maximum, 364 weeks). For nearly two-thirds of the drugs (52 [61%]), the maximum trial duration was less than 52 weeks. For 10 of the drugs (12%), the maximum trial duration was 3 years or more. Maximum duration of trials did not vary by therapeutic category, minimum age of enrollment, calendar year, or legislative mandate.

Conclusions and Relevance

Pediatric clinical trials designed to sufficiently investigate drug safety and efficacy to support FDA approval are of relatively limited duration. Given the potential long-term exposure of patients to these drugs, the clinical community should consider whether new approaches are needed to better understand the safety associated with long-term use of these drugs.

Longitudinal trends in renal function in chronic hepatitis B patients receiving oral antiviral treatment

BACKGROUND

Long term renal safety of antiviral agents against hepatitis B virus (HBV) has been debated.

AIM

To compare longitudinal trends of renal function among HBV mono-infected patients receiving entecavir (ETV), tenofovir disoproxil fumarate (TDF), and adefovir (ADV) in comparison to untreated subjects.

METHODS

A retrospective cohort consisting of 815 patients with chronic HBV infection was constructed. Serial estimated glomerular filtration rate (eGFR) was compared to the expected rate of age-dependent decline in eGFR, derived from the National Health and Nutrition Examination Survey (NHANES) data. Generalised estimating equations and linear mixed-effects models were used to compare trends in eGFR (in mL/min/1.73m² as a "unit").

RESULTS

In NHANES data (n = 23 051), each year of age was associated with a 0.86 unit decrease in eGFR in subjects without hypertension and 0.96 units with hypertension. The Stanford cohort consisted of patients who received ETV (n = 207), TDF (n = 191), ADV (n = 46) or no therapy (n = 371). After a median follow-up 4.0 (interquartile range: 1.9-6.5) years, there was no significant difference in the expected and observed rates of eGFR decline in untreated HBV patients. Patients receiving antiviral treatment experienced steeper reduction in renal function than expected. In the multivariable model, ETV was associated with eGFR loss at 1.81 units per year (P = 0.06, compared to untreated patients). TDF- and ADV-treated patients experienced significantly higher rate of eGFR loss at 2.21 and 2.63 units per year, respectively (both P < 0.01).

CONCLUSION

In this longitudinal cohort study, HBV patients receiving antiviral therapy, particularly TDF and ADV, experienced more rapid loss in eGFR.

Potential kidney toxicity from the antiviral drug tenofovir: new indications, new formulations, and a new prodrug

PURPOSE OF REVIEW

The antiviral agent tenofovir is highly effective for the treatment of HIV and hepatitis B virus infections, and the older prodrug tenofovir disoproxil fumarate (TDF) is also a component of daily preexposure prophylaxis (PrEP) to reduce the risk of HIV infection in high-risk populations. Although TDF is well tolerated, the potential for kidney and bone toxicity has important implications for public health given the large number of individuals exposed to TDF worldwide. This review summarizes the recent literature on kidney and bone health in individuals treated with TDF and the newer prodrug tenofovir alafenamide (TAF).

RECENT FINDINGS

Risk factors for TDF toxicity appear to be similar in patients treated for HIV or hepatitis B virus and in HIV-uninfected PrEP users, although drug-drug interactions are a more important concern in HIV-positive individuals. The risk of toxicity appears to be lower with TAF, but further studies are needed to confirm the safety of long-term use and to evaluate the efficacy of TAF-based PrEP.

SUMMARY

Nephrologists should be aware of the potential kidney and bone toxicity of TDF, as well as unique situations in which the newer prodrug TAF may contribute to kidney injury.