Ribavirin and abacavir drug interaction in HIV-HCV coinfected patients: fact or fiction?

Drug-drug interactions with candidate medications used for COVID-19 treatment: An overview

Drug-drug interaction (DDI) is a common clinical problem that has occurred as a result of the concomitant use of multiple drugs. DDI may occur in patients under treatment with medications used for coronavirus disease 2019 (COVID-19; i.e., chloroquine, lopinavir/ritonavir, ribavirin, tocilizumab, and remdesivir) and increase the risk of serious adverse reactions such as QT-prolongation, retinopathy, increased risk of infection, and hepatotoxicity. This review focuses on summarizing DDIs for candidate medications used for COVID-19 in order to minimize the adverse reactions.

Plasma and intracellular ribavirin concentrations are not significantly altered by abacavir in hepatitis C virus-infected patients

OBJECTIVES

The objective of this study was to evaluate the effects of abacavir on intracellular ribavirin triphosphate and plasma ribavirin trough concentrations.

METHODS

Hepatitis C virus-infected subjects who had been cured or failed prior treatment were randomized to 8 weeks of ribavirin alone (N = 14; weight-based dosing) or weight-based ribavirin + abacavir (N = 14; 300 mg orally every 12 h). Ribavirin trough concentrations were measured on days 14, 28, 42 and 56; PBMCs for ribavirin triphosphate determination were sampled on days 28 and 56, pre-dose and at 6 and 12 h post-dose. ClinicalTrials.gov: NCT01052701.

RESULTS

Twenty-six subjects completed the study (24 males, 17 Caucasians, median age 52 years); 2 were excluded for missed pharmacokinetic visits. Fourteen subjects received ribavirin + abacavir and 12 received ribavirin alone. Mean ± SD plasma ribavirin trough concentrations (μg/mL) on days 14, 28, 42 and 56, respectively, were not significantly different with coadministration of abacavir (1.54 ± 0.60, 1.93 ± 0.54, 2.14 ± 0.73 and 2.54 ± 1.05) compared with ribavirin alone (1.48 ± 0.32, 2.08 ± 0.41, 2.32 ± 0.47 and 2.60 ± 0.62) (P > 0.40). Mean ribavirin triphosphate intracellular concentrations (pmol/10(6) cells) on days 28 and 56, respectively, did not differ statistically between abacavir users (11.98 ± 9.86 and 15.87 ± 12.52) and non-users (15.91 ± 15.58 and 15.93 ± 12.69) (P > 0.4). Adverse events were mild or moderate, except for three grade 3 occurrences of transaminitis, cholecystitis and low absolute neutrophil count that resolved and were judged not attributable to study medications.

CONCLUSIONS

Abacavir did not significantly alter ribavirin or ribavirin triphosphate concentrations.

Effect of abacavir on sustained virologic response to HCV treatment in HIV/HCV co-infected patients, Cohere in Eurocoord

BACKGROUND

Contradicting results on the effect of abacavir (ABC) on hepatitis C virus (HCV) treatment responses in HIV/HCV co-infected patients have been reported. We evaluated the influence of ABC on the response to pegylated interferon (pegIFN) and ribavirin (RBV)-containing HCV treatment in HIV/HCV co-infected patients in a large European cohort collaboration, including data from different European countries.

METHODS

HIV/HCV co-infected patients were included if they were aged ≥16 years, received pegIFN alfa-2a or 2b and RBV combination treatment and were enrolled in the COHERE cohort collaboration. Logistic regression was used to evaluate the impact of abacavir on achieving a sustained virologic response (SVR) to HCV treatment.

RESULTS

In total 1309 HIV/HCV co-infected patients who had received HCV therapy were included, of whom 490 (37 %) had achieved an SVR. No statistically significant difference was seen for patients using ABC-containing regimens compared to patients using an emtricitabine + tenofovir (FTC + TDF)-containing backbone, which was the most frequently used backbone. In the multivariate analyses, patients using a protease inhibitor (PI)-boosted regimen were less likely to achieve an SVR compared to patients using a non-nucleoside reverse-transcriptase inhibitor (NNRTI)-based regimen (OR: 0.61, 95 % CI: 0.41-0.91). The backbone combinations zidovudine&lamivudine (AZT + 3TC) and stavudine&lamivudine (d4t + 3TC) were associated with lower SRV rates (0.45 (0.24-0.82) and 0.46 (0.22-0.96), respectively).

CONCLUSION

The results of this large European cohort study validate that SVR rates are generally not affected by ABC. Use of d4T or AZT as part of the HIV treatment regimen was associated with a lower likelihood of achieving an SVR.

Evidence-based consensus on the diagnosis, prevention and management of hepatitis C virus disease

Hepatitis C virus (HCV) is a potent human pathogen and is one of the main causes of chronic hepatitis round the world. The present review describes the evidence-based consensus on the diagnosis, prevention and management of HCV disease. Various techniques, for the detection of anti-HCV immunoglobulin G immunoassays, detection of HCV RNA by identifying virus-specific molecules nucleic acid testings, recognition of core antigen for diagnosis of HCV, quantitative antigen assay, have been used to detect HCV RNA and core antigen. Advanced technologies such as nanoparticle-based diagnostic assays, loop-mediated isothermal amplification and aptamers and Ortho trak-C assay have also come to the front that provides best detection results with greater ease and specificity for detection of HCV. It is of immense importance to prevent this infection especially among the sexual partners, injecting drug users, mother-to-infant transmission of HCV, household contact, healthcare workers and people who get tattoos and piercing on their skin. Management of this infection is intended to eradicate it out of the body of patients. Management includes examining the treatment (efficacy and protection), assessment of hepatic condition before commencing therapy, controlling the parameters upon which dual and triple therapies work, monitoring the body after treatment and adjusting the co-factors. Examining the treatment in some special groups of people (HIV/HCV co-infected, hemodialysis patients, renal transplanted patients).

Drug interactions between antiretrovirals and new or emerging direct-acting antivirals in HIV/hepatitis C virus coinfection

PURPOSE OF REVIEW

We reviewed the pharmacokinetic interactions between direct-acting antivirals against hepatitis C virus (HCV) and antiretroviral agents.

RECENT FINDINGS

Most relevant pharmacokinetic studies involve healthy individuals and refer to the already licensed HCV protease inhibitors, boceprevir and telaprevir. Data from a phase II clinical trial question the clinical relevance of the interactions between boceprevir and HIV protease inhibitors. The use of a higher dose of telaprevir appears to offset the effect of efavirenz on telaprevir metabolism according to another phase II trial. Boceprevir and particularly telaprevir substantially increase the exposure to maraviroc, similarly to other potent CYP3A4 inhibitors. Different dosages of faldaprevir and daclatasvir have been recommended to be used in combination with a boosted HIV protease inhibitor vs. an efavirenz-based antiretroviral regimen. HIV protease inhibitors appear to substantially increase the exposure to simeprevir. The interactions between sofosbuvir and most antiretroviral agents do not appear to be of clinical relevance or to require dosage modifications.

SUMMARY

The drug-drug interaction studies for HCV direct-acting antivirals and antiretrovirals are important in determining the appropriate drug combinations and dosages. The clinical implications of these interactions need further assessment in different categories of patients, including those with cirrhosis.

Use of first-generation HCV protease inhibitors in patients coinfected by HIV and HCV genotype 1

BACKGROUND

In HCV genotype 1-infected patients with HIV co-infection, tritherapy [HCV protease inhibitors (PIs) plus peg-interferon and ribavirin] has been shown to have an increased rate of sustained virological response. However, complex drug-to-drug interactions and tolerability issues remain a concern.

METHODS

Under the auspices of four French scientific societies of medicine, a committee was charged of establishing guidelines on the use of first-generation HCV PIs in these patients. This scientific committee based its work on preliminary results from tritherapy clinical trials in co-infected patients and, since data on these patients are still scarce, on the statements already made by the French Association for the Study of the Liver (AFEF) on the use of tritherapy in HCV mono-infected patients, written in May 2011 and updated in 2012. Each AFEF guideline concerning HCV monoinfection was examined to determine whether it could be used in the context of HIV/HCV coinfection.

RESULTS

These guidelines are addressed for the treatment of coinfected patients with various profiles, including treatment-naïve or patients with failure to previous bitherapy and mention those patients for whom tritherapy should start or those for whom it should be delayed. Preliminary results of triple therapy as well as factors associated to virological response are also discussed. Other issues include virological monitoring, clinical and virological criteria to stop therapy, practical treatment management, treatment adherence and the management of side effects and interactions with antiretroviral drugs. These guidelines were submitted for critical review to independent experts.

Hepatitis C virus infection in patients with HIV-1: epidemiology, natural history and management

Hepatitis C virus (HCV)-related liver diseases have contributed to increased morbidity and mortality in HIV-1-infected individuals in the era of effective antiretroviral therapy. HCV transmission patterns have changed among the HIV co-infected population during the last decade, with acute HCV infection emerging worldwide. HIV infection accelerates the progression of HCV-related liver diseases and consequently cirrhosis, liver failure, and hepatocellular carcinoma. However, the current standard treatment of HCV infection with pegylated interferon plus ribavirin results in only a limited viral response. Furthermore, cumbersome pill regimens, antiretroviral related hepatotoxicity, and drug interactions of HCV and HIV regimens complicate therapy strategies. Fortunately, in the near future, new direct-acting anti-HCV agents will widen therapeutic options for HCV/HIV co-infection. Liver transplantation is also gradually accepted as a therapeutic option for end stage liver disease of HCV/HIV co-infected patients.