Effects of Mild and Moderate Renal Impairment on Ombitasvir, Paritaprevir, Ritonavir, Dasabuvir, and Ribavirin Pharmacokinetics in Patients with Chronic HCV Infection

Efficacy and Safety of Ombitasvir plus Paritaprevir, Ritonavir and Ribavirin in Non-cirrhotic Treatment-naïve and Treatment-experienced Egyptians with Chronic HCV Genotype-4 Infection

Hepatitis C virus genotype 4 (HCV-GT4) is a risk factor for cirrhosis, hepatocellular carcinoma and liver failure. A combination of three new direct-acting antivirals ombitasvir, paritaprevir, and ritonavir has been recommended for treatment of HCV-GT4 infection. The current study was aimed to assess the efficacy and safety of this combination plus ribavirin in non-cirrhotic, treatment-naïve and -experienced Egyptians with HCV-GT4 infection in a real-world setting. A total of 255 Egyptians with HCV-GT4 infection were enrolled, including 82 treatment-experienced and 173 treatment-naïve patients. All of them completed 12-week treatment protocol of ombitasvir, paritaprevir and ritonavir as an oral dose combination with ribavirin. Virological response (VR) was measured, as well as the biochemical parameters related to treatment efficacy and adverse events at baseline and after treatment, at 4 (VR4) and 12 (VR12) weeks post-treatment. The results showed that the VR4 rates were 98.8% in both groups, and VR12 rates were 97.7% and 96.3% in treatment-naïve and -experienced patients, respectively, with no significant differences found between the groups concerning VR4 (P=0.9) and VR12 (P=0.3). The most common adverse events were headache and fatigue, which were significantly more common (P=0.001 and 0.003, respectively) in treatment-experienced than in treatment-naïve group. The quadruple regimen was well-tolerated, and the reported adverse events were generally mild to moderate. This real-world setting study confirms that the combination of ombitasvir, paritaprevir, ritonavir, and ribavirin is highly effective in the treatment of HCV- GT4 infection with a good safety and tolerability profile.

Treatment of hepatitis C infection among Egyptian hemodialysis patients: the dream becomes a reality

BACKGROUND AND AIMS

New direct-acting antiviral drugs have become the corner-stone treatment for HCV infection: they show promising results with accepted side-effects and low dropout rates. One of the available regimens is paritaprevir/ombitasvir/ritonavir (PTV/OMV/RTV). Our aim was to study the efficacy and safety of this drug regimen among HCV-positive hemodialysis patients.

METHODS

This prospective single-center study was performed in the Urology and Nephrology Center, Mansoura University, Egypt. Ninety-six maintenance hemodialysis patients were screened for HCV antibodies. Positive results were found in 46 patients (47.9%). HCV PCR was assessed in all HCV-antibody-positive patients; positive results were found positive for 38 (82%); all patients were HCV genotype 4. Four patients were excluded due to advanced liver cirrhosis, liver malignancy, or metastatic breast cancer. Thirty-four patients were prescribed PTV/OMV/RTV for 3 months to treat HCV.

RESULTS

Mean age was 43.2 ± 11.9 years. Most patients were male (67.6%). There was a rapid response to treatment: HCV PCR became negative by 4 weeks after starting treatment. By 12 and 24 weeks post-DAA therapy, there was a sustained viral response (SVR 12, SVR 24) in 100% of patients with improved liver-enzyme levels.

CONCLUSION

The PTV/OMV/RTV regimen was safe and effectively treated Egyptian HCV-positive genotype-4 hemodialysis patients.

Efficacy of ombitasvir/paritaprevir/ritonavir/ribavirin in management of HCV genotype 4 and end-stage kidney disease

BACKGROUND

Till now, pooled data about the safety and efficacy of different direct-acting antiviral (DAAs) regimens in different renal situations are still under evaluation.

AIM

To evaluate a real-life experience of the efficacy and safety of ombitasvir/paritaprevir/ritonavir plus ribavirin (OBV/PTV/r plus RIB) in patients with end-stage kidney disease (ESKD).

PATIENTS AND METHODS

Between January 2017 and January 2018, an open-label multicenter prospective study was designed to enroll all consecutive patients with proven CHC genotype 4 infections and concomitant ESKD based on estimated glomerular filtration rate (eGFR) with (HD group) or without hemodialysis (non-HD group). Patients were given a co-formula of OBV/PTV/r (25/150/100 mg) once-daily plus RIB was given for 12 weeks. Sustained virologic response (SVR 12) was the primary endpoint.

RESULTS

A total of 110 patients were enrolled. An overall SVR 12 was reported in 104 (94.5%) patients, and treatment failure were reported in 6 patients [2 patients (1.8%) were relapsed, and 4 patients (3.6%) patients were non-responders]. SVR12 was 96% in HD and 91.4% in non-HD patients (P = 0.286). There were no reported serious adverse events. Anemia was reported in 66.6% (n = 50) in HD group and in 31.4% (n = 11) in non-HD group.

CONCLUSION

Although it is still challenging, achievement of SVR12 in patients with chronic HCV and concomitant end-stage kidney disease in the era of DAAs became possible with a 12 weeks course of a co-formula of ombitasvir/paritaprevir /ritonavir plus ribavirin. CLINICALTRIALS.

GOV ID

NCT03341988.

Minor contribution of CYP3A5 to the metabolism of hepatitis C protease inhibitor paritaprevir in vitro

Paritaprevir (PTV) is a non-structural protein 3/4A protease inhibitor developed for the treatment of hepatitis C disease as a fixed dose combination of ombitasvir (OBV) and ritonavir (RTV) with or without dasabuvir. The aim of this study was to evaluate the effects of cytochrome P450 (CYP) 3A5 on in vitro PTV metabolism using human recombinant CYP3A4, CYP3A5 (rCYP3A4, rCYP3A5) and human liver microsomes (HLMs) genotyped as either CYP3A5*1/*1, CYP3A5*1/*3 or CYP3A5*3/*3. The intrinsic clearance (CL_int, V_max/K_m) for the production of a metabolite from PTV in rCYP3A4 was 1.5 times higher than that in rCYP3A5. The PTV metabolism in CYP3A5*1/*1 and CYP3A5*1/*3 HLMs expressing CYP3A5 was comparable to that in CYP3A5*3/*3 HLMs, which lack CYP3A5. CYP3A4 expression level was significantly correlated with PTV disappearance rate and metabolite formation. In contrast, there was no such correlation found for CYP3A5 expression level. This study represents that the major CYP isoform involved in PTV metabolism is CYP3A4, with CYP3A5 having a minor role in PTV metabolism. The findings of the present study may provide foundational information on PTV metabolism, and may further support dosing practices in HCV-infected patients prescribed PTV-based therapy.

Effects of chronic kidney disease stage 4, end-stage renal disease, or dialysis on the plasma concentrations of ombitasvir, paritaprevir, ritonavir, and dasabuvir in patients with chronic HCV infection: pharmacokinetic analysis of the phase 3 RUBY-I and RUBY-II trials

PURPOSE

To characterize the pharmacokinetics of ombitasvir, paritaprevir, ritonavir, dasabuvir, and ribavirin in hepatitis C virus (HCV)-infected patients with chronic kidney disease stage 4 (CKD4) or end-stage renal disease (ESRD), including those on dialysis, in the open-label phase 3 RUBY-I and RUBY-II studies.

METHODS

Patients (n = 18 CKD4, n = 68 ESRD) received ombitasvir/paritaprevir/ritonavir 25/150/100 mg once daily ± dasabuvir 250 mg twice daily ± ribavirin 200 mg once daily for 12 or 24 weeks. Intensive pharmacokinetic samples were collected from ten patients; sparse samples were collected from all patients. Arterial and venous samples were collected from three patients during hemodialysis. Area under the plasma concentration-time curve (AUC) was estimated using noncompartmental analyses for intensive data, and steady-state trough concentrations (C_trough) were obtained from the sparse data. Pharmacokinetic results from RUBY-I and RUBY-II were compared empirically to historical data.

RESULTS

The AUC values of ombitasvir, paritaprevir, ritonavir, and dasabuvir were comparable between CKD4 and ESRD patients and were within the range of values observed in historical studies; dialysis had no effect on drug exposures. Ribavirin was extracted during hemodialysis but had similar exposures on dialysis and non-dialysis days. Individual steady-state C_trough values for each drug overlapped between CKD4 and ESRD patients, and values in both groups were similar to historical values.

CONCLUSION

Plasma concentrations of ombitasvir, paritaprevir, ritonavir, and dasabuvir were not altered by renal impairment or dialysis, suggesting these agents can be administered to HCV-infected CKD4 or ESRD patients, including those on dialysis, without dose adjustment.

TRIAL REGISTRATION

Clinicaltrials.gov identifiers: NCT02207088 (RUBY-I) and NCT02487199 (RUBY-II).

Clinical Pharmacokinetics of Paritaprevir

Paritaprevir is a potent hepatitis C virus (HCV) nonstructural (NS) protein 3/4A protease inhibitor that is used in combination with other direct-acting antivirals (DAAs) for the treatment of chronic HCV infection. Paritaprevir is primarily metabolized by cytochrome P450 (CYP) 3A4 and is administered with a low dose of ritonavir to achieve drug concentrations suitable for once-daily dosing. Coadministration of paritaprevir with ritonavir increases the half-life of single-dose paritaprevir from approximately 3 h to 5-8 h, doubles the time to maximum plasma concentration (T _max) from 2.3 to 4.7 h, and increases exposures 30-fold for maximum observed plasma concentration (C _max), 50-fold for area under the plasma concentration-time curve (AUC), and >300-fold for trough concentration (C ₂₄). Paritaprevir displays highly variable, nonlinear pharmacokinetics, with C _max and AUC increasing in a greater than dose proportional manner when administered with or without ritonavir. In the presence of ritonavir, paritaprevir is excreted mostly unchanged in feces via biliary excretion. Paritaprevir exposures are higher in Japanese subjects compared with Caucasian subjects; however, no dose adjustment is needed for Japanese patients as the higher exposures are safe and well tolerated. The pharmacokinetic characteristics of paritaprevir are similar between healthy subjects and HCV-infected patients, and are not appreciably altered by mild or moderate hepatic impairment or mild, moderate, or severe renal impairment, including those on dialysis. Paritaprevir exposures are increased in patients with severe hepatic impairment. Although the presence of a low dose of ritonavir in paritaprevir-containing regimens increases the likelihood of drug-drug interactions, results from several drug interaction studies demonstrated that paritaprevir-containing regimens can be coadministered with many comedications that are commonly prescribed in HCV-infected patients.

Clinical Pharmacokinetics of Dasabuvir

Dasabuvir is a nonstructural (NS) 5B non-nucleoside inhibitor of the hepatitis C virus (HCV) used in combination with ombitasvir/paritaprevir/ritonavir for the treatment of chronic HCV infection. It is primarily metabolized by cytochrome P450 (CYP) 2C8, with a minor contribution from CYP3A. Biotransformation of dasabuvir forms the M1 metabolite, which retains antiviral activity. Dasabuvir exhibits linear pharmacokinetics with a terminal half-life of approximately 5-8 h, allowing for twice-daily dosing. The M1 metabolite of dasabuvir is the major metabolite in plasma and has a half-life similar to that of dasabuvir. Dasabuvir exposures in Asian subjects are comparable with Caucasian subjects. The pharmacokinetic characteristics of dasabuvir are similar between healthy subjects and HCV-infected patients, and are not appreciably altered by mild, moderate, or severe renal impairment or dialysis. Dasabuvir pharmacokinetic parameters were not significantly altered in subjects with mild or moderate hepatic impairment; however, exposures were significantly increased in subjects with severe hepatic impairment. Dasabuvir should be administered with food to maximize absorption. Coadministration of dasabuvir with a strong CYP2C8 inhibitor increased dasabuvir exposures by greater than tenfold, whereas coadministration with strong CYP3A inhibitors increased dasabuvir exposures by less than 50%. Furthermore, coadministration of dasabuvir with a CYP3A inducer decreased dasabuvir exposures by 55-70%. Coadministration of dasabuvir with strong CYP2C8 inhibitors or strong CYP3A/CYP2C8 inducers is contraindicated. Results from several drug interaction studies demonstrated that dasabuvir in combination with ombitasvir/paritaprevir/ritonavir can be coadministered with most comedications that are commonly prescribed in HCV-infected patients.

Clinical Pharmacokinetics of Ombitasvir

Ombitasvir is a potent, nonstructural protein 5A inhibitor of the hepatitis C virus (HCV) that is used in combination with other direct-acting antivirals for the treatment of chronic HCV infection. Ombitasvir is predominantly metabolized by amide hydrolysis followed by oxidative metabolism and is a substrate of P-glycoprotein. Ombitasvir displays linear pharmacokinetics with minimal accumulation and is eliminated via metabolism and biliary excretion. A negligible amount of unchanged drug is excreted in urine. Exposures are comparable across Chinese, Japanese, and non-Asian subjects. The pharmacokinetic characteristics of ombitasvir are similar in healthy subjects and HCV-infected patients, and are not appreciably altered by hepatic or renal impairment. Results from several drug interaction studies demonstrated that ombitasvir has a low potential for drug interactions.

Retreatment Efficacy of Sofosbuvir/Ombitasvir/Paritaprevir/Ritonavir + Ribavirin for Hepatitis C Virus Genotype 4 Patients

BACKGROUND

The current standard of care for patients with chronic hepatitis C virus (HCV) infection is a combination of direct-acting antiviral agents (DAAs). However, rare clinical trials have been reported on the combination regimen of sofosbuvir (SOF) with ombitasvir, paritaprevir, and ritonavir (OBV/PTV/r) plus ribavirin (RBV) for treated patients with HCV genotype 4 (GT4) infection.

AIMS

To clarify the retreatment efficacy and safety of the recent regimen, SOF with OBV/PTV/r + RBV, for chronic HCV GT4-experienced patients who failed treatment with DAA-based regimens.

METHODS

A total of 113 treatment-experienced patients were allocated for the completion of their treatment period. The enrolled patients were treated orally with SOF plus a fixed dose combination of OBV/PTV/r + RBV, which was administered orally based on the patients' tolerability. The primary end point was a sustained virological response (HCV RNA < 15 IU/mL), observed 12 weeks after the end of the treatment (SVR12).

RESULTS

Among all patients, the treatment-experienced patients with SOF plus OBV/PTV/r + RBV had a higher SVR12 rate (97%; 109/113). Further, SVR12 was achieved by 98% (81/83) of non-cirrhotic patients and 93% (28/30) of cirrhotic patients. Additionally, the most common adverse events reported included fatigue, headache, insomnia, nausea, and dyspnea.

CONCLUSIONS

The recent multi-targeted regimen of SOF plus OBV/PTV/r + RBV was well tolerated and achieved excellent SVR rates among retreatment-experienced Egyptian patients with prior DAA treatments failure, thus providing an alternative regimen for the retreatment of difficult-to-cure HCV GT4 patients.

Liver decompensation predicts ribavirin overexposure in hepatitis C virus patients treated with direct-acting antivirals

AIM

To determine whether ribavirin (RBV) concentrations differ according to cirrhosis stage among cirrhotic patients treated with interferon-free regimens.

METHODS

We included patients with hepatitis C virus and cirrhosis [Child-Pugh (CP) A or B], Glomerular Filtration Rate ≥ 60 mL/min, who started therapy with DAAs and weight-based RBV between October 2014 and February 2016. RBV plasma levels were assessed during the treatment. We focused our analysis on the first 8 wk of therapy.

RESULTS

We studied 68 patients: 54 with compensated (CP-B) and 14 with decompensated (CP-A) cirrhosis. Patients with decompensated cirrhosis displayed significantly higher RBV concentrations than those with compensated cirrhosis at week 1, 2, 4 and 8 (P < 0.035). RBV levels were positively correlated with Hb loss over the treatment (P < 0.04). Majority (71%) of CP-B patients required a RBV dosage reduction during the treatment. After adjustment for confounders, Child-Pugh class remained significantly associated (95%CI: 35, 348, P = 0.017) to RBV levels, independently from baseline per-Kg RBV dosage.

CONCLUSION

Liver decompensation might affect RBV clearance leading to an overexposure and increased related toxicities in decompensated cirrhosis. Our findings underscore the importance of an early ribavirin therapeutic drug monitoring and suggest that an initial lower RBV dose, rather than weight-based, might be considered in those with advanced liver disease (CP-B) treated with direct-acting antivirals.

Combination Therapy with Ombitasvir/Paritaprevir/Ritonavir for Dialysis Patients Infected with Hepatitis C Virus: A Prospective Multi-Institutional Study

Hepatitis C virus (HCV) infection is common in dialysis patients worldwide and nosocomial HCV spread within dialysis facilities continues to develop. Combination therapy with daclatasvir and asunaprevir (DCV/ASV) that has proven efficacy for dialysis patients infected with genotype 1b HCV (HCV/1b) has several concerns in Japan. The recently available combination therapy with ombitasvir, paritaprevir, and ritonavir (OBV/PTV/r) is not contraindicated in patients with chronic renal failure and has more safety profile and shorter treatment period than that with DCV/ASV. We evaluated the effects of combination therapy with OBV/PTV/r in four dialysis patients infected with HCV/1b, who were eligible for our study. On-treatment assessments included standard laboratory testing, serum HCV RNA and symptom-directed physical examinations. Three patients had a sustained virological response at 12 weeks after treatment, but one remaining patient had viral breakthrough. Notably, the patient with viral breakthrough had been coinfected with HCV/1b and HCV/2b; namely, HCV/2b with resistance-associated variations was not eradicated by the combination therapy. Among the three patients responsive to the combination therapy, one patient complained of appetite loss and itching, while in another patient the therapy was discontinued due to itching, exacerbation of wamble, and a falling tendency probably due to interaction with valsartan. These AEs were ameliorated or disappeared after the completion of the therapy. The significance of our study is persuasive virological evaluation associated to the combination therapy and reasonable interpretation of AEs. In conclusion, combination therapy with OBV/PTV/r may have promise as an efficacious therapy, but caution regarding AEs should be practiced.

Special populations: treating hepatitis C in patients with decompensated cirrhosis and/or advanced renal impairment

Direct-acting antivirals have revolutionized the treatment of hepatitis C. Sustained virological response rates of at least 95% have become common in the general population. However, along with the ageing of the HCV population, physicians face a growing group of HCV-infected patients with advanced liver and/or renal impairment. The safety and efficacy of treatment remains a clinical challenge in these patients. This review focuses on the current state of knowledge and treatment regimens in patients with decompensated cirrhosis and severe renal impairment. It shows that distinct interferon-free treatments can achieve favourable sustained virological response rates in these difficult-to-treat patients. Moreover, pitfalls and special considerations as well as new emerging challenges in an era of interferon-free regimens will be presented in this article.