Exploring the influence of renal dysfunction on the pharmacokinetics of ribavirin after oral and intravenous dosing

Oral Versus Aerosolized Ribavirin for the Treatment of Respiratory Syncytial Virus Infections in Hematopoietic Cell Transplant Recipients

Background

The use of oral ribavirin (RBV) for respiratory syncytial virus (RSV) infections is not well studied. With the drastic increase in the cost of aerosolized RBV, we aimed to compare outcomes of hematopoietic cell transplant (HCT) recipients treated with oral or aerosolized RBV for RSV infections.

Methods

We reviewed the records of 124 HCT recipients with RSV infections treated with oral or aerosolized RBV from September 2014 through April 2017. An immunodeficiency scoring index (ISI) was used to classify patients as low, moderate, or high risk for progression to lower respiratory infection (LRI) or death.

Results

Seventy patients (56%) received aerosolized RBV and 54 (44%) oral RBV. Both groups had a 27% rate of progression to LRI (P = 1.00). Mortality rates did not significantly differ between groups (30-day: aerosolized 10%, oral 9%, P = 1.00; 90-day: aerosolized 23%, oral 11%, P = .10). Classification and regression tree analysis identified ISI ≥7 as an independent predictor of 30-day mortality. For patients with ISI ≥7, 30-day mortality was significantly increased overall, yet remained similar between the aerosolized and oral therapy groups (33% for both). After propensity score adjustment, Cox proportional hazards models showed similar mortality rates between oral and aerosolized therapy groups (30-day: hazard ratio [HR], 1.12 [95% confidence interval {CI}, .345–3.65, P = .845).

Conclusions

HCT recipients with RSV infections had similar outcomes when treated with aerosolized or oral RBV. Oral ribavirin may be an effective alternative to aerosolized RBV, with potential significant cost savings.

Considerations for Medications Commonly Utilized in the Oncology Population in the Intensive Care Unit

An increasing number of oncologic patients are presenting to the intensive care unit with complications from both their chronic disease states and cancer therapies due to improved survival rates. The management of these patients is complex due to immunosuppression (from the malignancy and/or treatment), metabolic complications, and diverse medication regimens with the potential for significant drug-drug interactions and overlapping adverse effects. This chapter will provide clinicians with an overview of non-chemotherapy medications frequently encountered in the critically ill oncologic patient, with a focus on practical considerations.

Ribavirin: pharmacology, multiple modes of action and possible future perspectives

Ribavirin is a unique guanosine analog with broad-spectrum activity against many RNA and DNA viruses. In addition to its mutational properties, ribavirin exerts extensive perturbation of cellular and viral gene expression. Furthermore, recent advances indicate that the impact of ribavirin on divergent cellular and viral pathways may be concentration dependent. This review aims at providing an overview of the pharmacology and multiple modes of action of ribavirin as well as pointing to possible novel future uses.

Pharmacokinetics, Efficacy, and Safety of Hepatitis C Virus Drugs in Patients with Liver and/or Renal Impairment

Hepatitis C virus (HCV)-infected patients often suffer from liver cirrhosis, which can be complicated by renal impairment. Therefore, in this review we describe the treatment possibilities in HCV patients with hepatic and renal impairment. Cirrhosis alters the structure of the liver, which affects drug-metabolizing enzymes and drug transporters. These modifications influence the plasma concentration of substrates of drugs metabolized/transported by these enzymes. The direct-acting antivirals (DAAs) are substrates of, for example, cytochrome P450 enzymes in the liver. Most DAAs are not studied in HCV-infected individuals with decompensated cirrhosis, and therefore awareness is needed when these patients are treated. Most DAAs are contraindicated in cirrhotic patients; however, patients with a Child-Pugh score of B or C can be treated safely with a normal dose sofosbuvir plus ledipasvir or daclatasvir, in combination with ribavirin. Patients with renal impairment (glomerular filtration rate [GFR] <90 mL/min) or who are dependent on dialysis often tolerate ribavirin treatment poorly, even after dose adjustments. However, most DAAs can be used at the normal dose because DAAs are not renally excreted. To date, grazoprevir plus elbasvir is the preferred DAA regimen in patients with renal impairment as data are pending for sofosbuvir patients with GFR <30 mL/min (as for ledipasvir and velpatasvir). However, sofosbuvir has been used in a small number of patients with severe renal impairment and, based on these trials, we recommend sofosbuvir 400 mg every day when no other DAA regimen is available. Ledipasvir and velpatasvir are not recommended in patients with severe renal impairment.

Does Secretory Clearance Follow Glomerular Filtration Rate in Chronic Kidney Diseases? Reconsidering the Intact Nephron Hypothesis

Drug‐dose modification in chronic kidney disease (CKD) utilizes glomerular filtration rate (GFR) with the implicit assumption that multiple renal excretory processes decline in parallel as CKD progresses. We compiled published pharmacokinetic data to evaluate if GFR predicts renal clearance changes as a function of CKD severity. For each drug, we calculated ratio of renal clearance to filtration clearance (Rnf). Of 21 drugs with Rnf >0.74 in subjects with GFR >90 mL/min (implying filtration and secretion), 13 displayed significant change in Rnf vs. GFR (slope of linear regression statistically different from zero), which indicates failure of GFR to predict changes in secretory clearance. The dependence was positive (n = 3; group A) or negative (n = 10; group B). Eight drugs showed no correlation (group C). Investigated drugs were small molecules, mostly hydrophilic, and ionizable, with some characterized as renal transporter substrates. In conclusion, dosing adjustments in CKD require refinement; in addition to GFR, biomarkers of tubular function are needed for secreted drugs.

Hematological adverse effects and pharmacokinetics of ribavirin in pigs following intramuscular administration

Ribavirin (RBV) is a synthetic guanosine analog that is used as a drug against various viral diseases in humans. The in vitro antiviral effects of ribavirin against porcine viruses were demonstrated in several studies. The purposes of this study were to evaluate the adverse effects and pharmacokinetics of ribavirin following its intramuscular (IM) injection in pigs. Ribavirin was formulated as a double-oil emulsion (RBV-DOE) and gel (RBV-Gel), which were injected into the pigs as single-dose IM injections. After injection of RBV, all of the pigs were monitored. The collected serum and whole blood samples were analyzed by liquid chromatography-tandem mass spectrometry and complete blood count analysis, respectively. All of the ribavirin-treated pigs showed significant decreases in body weight compared to the control groups. Severe clinical signs including dyspnea, anorexia, weakness, and depression were present in ribavirin-treated pigs until 5 days postinjection (dpi). The ribavirin-treated groups showed significant decrease in the number of red blood cells and hemoglobin concentration until 8 dpi. The mean half-life of the RBV-DOE and RBV-Gel was 27.949 ± 2.783 h and 37.374 ± 3.502 h, respectively. The mean peak serum concentration (C_max ) and area under the serum concentration-time curve from time zero to infinity (AUC_inf ) of RBV-DOE were 8340.000 ± 2562.577 ng/mL and 16 0095.430 ± 61 253.400 h·ng/mL, respectively. The C_max and AUC_inf of RBV-Gel were 15 300.000 ± 3764.306 ng/mL and 207526.260 ± 63656.390 h·ng/mL, respectively. The results of this study provided the index of side effect and pharmacokinetics of ribavirin in pigs, which should be considered before clinical application.

Autophagy suppression sensitizes glioma cells to IMP dehydrogenase inhibition-induced apoptotic death

We investigated the role of autophagy, a process of controlled self-digestion, in the in vitro anticancer action of the inosine monophosphate dehydrogenase (IMPDH) inhibitor ribavirin. Ribavirin-triggered oxidative stress, caspase activation, and apoptotic death in U251 human glioma cells were associated with the induction of autophagy, as confirmed by intracellular acidification, appearance of autophagic vesicles, conversion of microtubule associated protein 1 light chain 3 (LC3)-I to autophagosome-associated LC3-II, and degradation of autophagic target p62/sequestosome 1. Ribavirin downregulated the activity of autophagy-inhibiting mammalian target of rapamycin complex 1 (mTORC1), as indicated by a decrease in phosphorylation of the mTORC1 substrate ribosomal p70S6 kinase and reduction of the mTORC1-activating Src/Akt signaling. Guanosine supplementation inhibited, while IMPDH inhibitor tiazofurin mimicked ribavirin-mediated autophagy induction, suggesting the involvement of IMPDH blockade in the observed effect. Autophagy suppression by ammonium chloride, bafilomycin A1, or RNA interference-mediated knockdown of LC3 sensitized glioma cells to ribavirin-induced apoptosis. Ribavirin also induced cytoprotective autophagy associated with Akt/mTORC1 inhibition in C6 rat glioma cells. Our data demonstrate that ribavirin-triggered Akt/mTORC1-dependent autophagy counteracts apoptotic death of glioma cells, indicating autophagy suppression as a plausible therapeutic strategy for sensitization of cancer cells to IMPDH inhibition.

Population Pharmacokinetics of Paritaprevir, Ombitasvir, Dasabuvir, Ritonavir, and Ribavirin in Patients with Hepatitis C Virus Genotype 1 Infection: Combined Analysis from 9 Phase 1b/2 Studies

Direct-acting antiviral agents (DAAs) are established as the standard of care for chronic hepatitis C virus (HCV) infection. One of the newest additions to the HCV arsenal is an oral three-DAA combination therapy (i.e., the 3D regimen) that does not require concomitant use of pegylated interferon. The clinical development program for the 3D regimen has yielded a robust dataset that is inclusive of various dosing schemes and a diverse patient population. Using data from nine phase 1b/2a/2b studies that enrolled patients with HCV genotype 1 infection, population pharmacokinetic models were developed for each component of the 3D regimen (ombitasvir, paritaprevir, ritonavir, and dasabuvir) and for ribavirin, an adjunctive therapy used to enhance therapeutic efficacy in some populations. Formulation effects, accumulation, relative bioavailability, and interactions between DAAs were assessed during model development, and demographic and clinical covariates were identified and evaluated for their effects on drug exposures. Proposed models were assessed via goodness-of-fit plots, visual predictive checks, and bootstrap evaluations. Population pharmacokinetic models adequately described their respective plasma concentration-time data with precise and reliable model parameter estimates and with good predictive performance. Covariates, including age, sex, body weight, cytochrome P450 2C8 inhibitor use, non-Hispanic ethnicity, and creatinine clearance, were associated with apparent clearance and/or apparent volume parameters; however, the magnitude of effect on drug exposure was modest and not considered to be clinically significant. No patient-related or clinical parameters were identified that would necessitate dose adjustment of the 3D regimen in patients with HCV genotype 1 infection.

Telaprevir and ribavirin interaction: higher ribavirin levels are not only due to renal dysfunction during triple therapy

A higher incidence of anemia has been observed during the treatment of hepatitis C virus genotype 1 (HCV-1) infection with pegylated alpha interferon (pegIFN-α), ribavirin, and telaprevir. We assessed the impacts that concomitant administration of telaprevir and changes in the glomerular filtration rate have on ribavirin plasma levels. The minimum concentrations of ribavirin in plasma (ribavirin Cmin) determined during triple therapy including telaprevir were compared with those observed after telaprevir withdrawal and those observed in the same subjects and in a large cohort during a previous course of pegIFN-α plus ribavirin. Intensive pharmacokinetic sampling for ribavirin was performed at steady state during the triple-therapy phase. Ribavirin levels were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Twenty-seven HCV-1/HIV-coinfected patients were enrolled. The median ribavirin Cmin for triple therapy (4.08 μg/ml; range, 2.14 to 5.56 μg/ml) was higher than that observed after telaprevir withdrawal (1.96 μg/ml; range, 0.41 to 3.45 μg/ml) (P < 0.001) and that observed for 125 HCV-1/HIV-coinfected patients treated only with pegIFN-α plus ribavirin (1.65 μg/ml; range, 0.41 to 5.56 μg/ml) (P < 0.001). The estimated glomerular filtration rate (eGFR) decreased >20% from the baseline value in 11 of 27 patients and became normal after telaprevir removal in almost all cases. There was a negative correlation between eGFR and ribavirin clearance (r(2) = 0.257; P = 0.064) but not the ribavirin area under the concentration-time curve from 0 to 12 h (AUC0-12) (r(2) = 0.001; P = 0.455). Thus, there is a significant pharmacokinetic interaction between telaprevir and ribavirin that results in very high ribavirin levels, which explains the excess of toxicity observed with this drug combination. A blockade of the proximal tubular transporters might be implicated in both the increase in plasma creatinine and the high ribavirin levels. (This study has been registered at ClinicalTrials.gov under registration no. NCT01818856.).

Telaprevir enhances ribavirin-induced anaemia through renal function impairment

BACKGROUND

Alterations in renal function have been described with telaprevir (TVR). We examined the relationship between ribavirin (RBV) trough concentration (C), estimated glomerular filtration rate (eGFR) and severe anaemia, before and after TVR introduction in HIV-HCV-coinfected patients included in ANRS HC26 TelapreVIH study.

METHODS

69 HIV-HCV genotype-1 coinfected patients received 4 weeks of pegylated interferon (PEG-IFN)-α2a/RBV, followed by 12 weeks of TVR/PEG-IFN/RBV, then 32 to 56 weeks of PEG-IFN/RBV. RBV C was determined at week (W)4, W8 and W20/24. eGFR was estimated by the Modification of the Diet in Renal Disease (MDRD) equation. Severe anaemia was defined as haemoglobin <70 g/l, RBV dose reduction, prescription of erythropoietin or blood transfusion.

RESULTS

67 patients were analysed. eGFR remained normal between baseline (97.9 ml/min) and W4 (103.4 ml/min), declined to 86.3 ml/min at W8 (P<0.0001), stabilized until W16 and increased back to baseline level at W20 (98.4 ml/min). RBV C increased from 1.88 mg/l at W4 to 2.88 mg/l at W8 (P<0.0001), then decreased to 2.73 mg/l at week 20/24 (P=0.015). An inverse correlation was observed between W8 eGFR and W8 RBV C (r2=0.429; P=0.0005). RBV C≥3 mg/l was observed in 12% of patients at W4, 45% at W8 (P<0.0001) and 38% at W20/24 (P=0.0005). Severe anaemia was observed in 23.9% of patients at W4 and 45.3% at W8. RBV C≥3 mg/l at W8 (OR 7.7 [95% CI 2.2, 27.4]) and baseline haemoglobin <150 g/l (OR 6.4 [1.7, 23.8]) were independently associated with W8 severe anaemia.

CONCLUSIONS

Association of TVR to PEG-IFN/RBV was associated with a decrease in eGFR and increase in RBV C, leading to severe anaemia in 45% of patients.