Telaprevir-S isomer enhances ribavirin exposure and the ribavirin-related haemolytic anaemia in a concentration-dependent manner

Pharmacogenetics of the anti-HCV drug sofosbuvir: a preliminary study

Background

Sofosbuvir is a potent nucleotide HCV NS5B polymerase inhibitor that is also a P-glycoprotein (encoded by the ABCB1 gene) and breast cancer resistance protein (encoded by the ABCG2 gene) substrate. Concerning previous anti-HCV therapies, pharmacogenetics had a significant impact, particularly considering the association of interleukin28B polymorphisms with dual-therapy (ribavirin + pegylated IFN) outcomes.

Objectives

In this work, we investigated the association between sofosbuvir and its prevalent metabolite (GS-331007) plasma concentrations at 1 month of therapy and genetic variants (SNPs) in genes encoding transporters and nuclear factors (ABCB1, ABCG2 and HNF4α) related to sofosbuvir transport.

Patients and methods

Allelic discrimination was performed through real-time PCR, whereas plasma concentrations were evaluated through liquid chromatography. One hundred and thirteen patients were enrolled.

Results

Sofosbuvir concentrations were below the limit of quantification since the drug was converted into its GS-331007 metabolite. ABCB1 2677 G>T (P = 0.044) and HNF4α 975 C>G (P = 0.049) SNPs were associated with GS-331007 metabolite plasma concentrations. In linear multivariate analysis, liver stiffness, insulin resistance, baseline haemoglobin and haematocrit and SNPs in the ABCB1 gene (3435 CT/TT and 1236 TT genotypes) were significant predictors of GS-331007 concentrations. Furthermore, we performed sub-analyses considering the anti-HCV concomitant drug and HCV genotype, identifying specific polymorphisms associated with GS-331007 plasma concentrations: ABCB1 3435 C>T and HNF4α975 C>G in patients treated with daclatasvir, ABCB1 2677 G>T with ledipasvir and ABCB1 3435 C>T, ABCB1 2677 G>T, ABCG2 421 C>A and ABCG2 1194 + 928 C>A with ribavirin.

Conclusions

In this study we suggested sofosbuvir GS-331007 metabolite plasma levels were affected by variants in the ABCB1 and HNFα genes.

Role of simeprevir plasma concentrations in HCV treated patients with dermatological manifestations

BACKGROUND AND AIMS

Up till now the role of simeprevir plasma concentrations has not been described in treated patients affected by chronic hepatitis C and with dermatological side-effects. In this study, we have evaluated a possible relationship between plasma levels and the onset of skin complaints for the first time.

METHODS

We report a clinical and pharmacokinetic analysis of 56 patients treated with simeprevir-based therapies.

RESULTS

Simeprevir plasma concentrations were significantly related to dermatological side-effects at early time-points (P<0.001). In logistic regression, simeprevir concentrations at 1 week was the best predictive factor forskin symptoms (OR=1.901, 95%IC: 1.001-2.304; P=0.007).

CONCLUSION

Simeprevir plasma measurements could be a useful tool in a real-life clinical setting for prevention of dermatological symptoms.

Estimated glomerular filtration rate but not solute carrier polymorphisms influences anemia in HIV-hepatitis C virus coinfected patients treated with boceprevir or telaprevir-based therapy

OBJECTIVES

Ribavirin (RBV) induced anemia may be influenced by host genetic factors affecting RBV transport solute carrier (SLC) or metabolism inosine triphosphatase (ITPA), as already reported. We investigated the influence of single nucleotide polymorphisms (SNPs) on SLC genes on anemia, RBV trough concentration (Ctrough) and response in HIV-hepatitis C virus coinfected patients receiving triple therapy with boceprevir or telaprevir.

METHODS

Patients from the ANRS HC26/HC27 studies were genotyped for SLC28A3 SNPs (rs10868138 and rs56350726) and SL29A1 SNPs (rs760370). Hemoglobin (Hb) decline was collected at baseline day 0 (D0), week 4 (W4) and week 8 (W8), and RBV Ctrough was measured at W4 and W8 by HPLC. A multivariate analysis including SLC SNPs, estimated glomerular filtration rate (eGFR), ITPA deficiency and RBV Ctrough was performed to determine predictive factors of anemia and response.

RESULTS

SLC genotyping was performed in 130 patients. Neither SLC28A3 nor SLC29A1 SNPs were associated with Hb decline both at W4 and W8. No association was found between SLC polymorphisms and RBV Ctrough. Independent predictive factors of Hb decline at W4 were D0 Hb, ITPA deficiency and W4 RBV Ctrough in the multivariate analysis (P < 0.05). Only D0 Hb, W4 RBV Ctrough and eGFRD0-W8 were predictive of anemia at W8 (P < 0.05). Response was not influenced by SLC SNPs.

CONCLUSION

eGFR, but not SLC polymorphisms, influences anemia in HIV-hepatitis C virus coinfected patients receiving boceprevir-based or telaprevir-based therapy. RBV is still a cornerstone of hepatitis C treatment, thus renal function and RBV Ctrough should be monitored in patients receiving RBV regimen combined with first-generation direct-acting antiviral agent.

Pharmacogenetics of ribavirin-induced anemia in HCV patients

Dual therapy (pegylated interferon plus ribavirin) was considered the standard of care for hepatitis C virus (HCV) treatment until 2011, when the first-wave direct-acting antivirals were added to this regimen for HCV genotype-1 patients to increase the sustained virological response rate. The second-wave direct-acting antivirals entered the clinical use also in some ribavirin (RBV)- and/or interferon-free combinations. Nevertheless, since some of the new therapeutic regimens also include RBV and its use results still associated with hemolytic anemia, this requires countermeasures to be prevented. These include the identification of several host predictive factors involved in RBV absorption, distribution, metabolism, elimination and many others that might influence this toxic effect. For this reason, we provided an overview of the potential role of pharmacogenomics in predisposing RBV-treated HCV patients to anemia.

A UHPLC-MS/MS method for the quantification of direct antiviral agents simeprevir, daclatasvir, ledipasvir, sofosbuvir/GS-331007, dasabuvir, ombitasvir and paritaprevir, together with ritonavir, in human plasma

To date, the new standard for treatment of chronic hepatitis C is based on the administration of novel direct acting antivirals. Among these, sofosbuvir, simeprevir, daclatasvir, ledipasvir, dasabuvir, ombitasvir and paritaprevir already entered the clinical use. Anyway, since few pharmacokinetic studies have been conducted on these drugs in a "real life" context poor knowledge is available about their optimal therapeutic range. Without this background, therapeutic drug monitoring is not applicable for treatment optimization. Up to now, a few methods are reported to quantify these drugs in human plasma, and none of them in a simultaneous way. The aim of this work was to develop and validate a simple, fast and cheap, but still reliable UHPLC-MS/MS method for the quantification of these drugs, feasible for a clinical routine use. Solid phase extraction was performed using HLB C18 96-well plates. Chromatographic separation was performed on a BEH C18 1.7μm, 2.1mm×50mm column, settled at 50°C, with a gradient run of two mobile phases: ammonium acetate 5mM (pH 9.5) and acetonitrile, with a flow rate of 0.4mL/min for 5min. Tandem-mass detection was carried out in positive electrospray ionization mode. Both inter and intraday imprecision and inaccuracy were below 15%, as required by FDA guidelines, while both recoveries and matrix effects resulted within the acceptance criteria. The method was tested on 80 patients samples with good performance. Being robust, simple and fast and requiring a low plasma volume, this method resulted eligible for a clinical routine use.

Modeling Ribavirin-Induced Anemia in Patients with Chronic Hepatitis C Virus

Ribavirin remains an important component of hepatitis C treatment in certain clinical scenarios, but it causes hemolytic anemia. A quantitative understanding of the ribavirin exposure-anemia relationship is important in dose individualization/optimization. We developed a model relating ribavirin triphosphate (RTP) exposure in red blood cells (RBCs), RBC lifespan, feedback regulation of RBC production when anemia occurs, and the resulting hemoglobin decline. Inosine triphosphatase (ITPA) and interleukin 28B (IL28B) genetics were found to be significant covariates. Clinical trial simulations predicted that anemia is least severe in IL28B non-CC (rs12979860, CT or TT), ITPA variant subjects, followed by IL28B non-CC, ITPA wild-type, IL28B CC, ITPA variant, and IL28B CC, ITPA wild-type subjects (most severe). Reducing the ribavirin dose from 1,200/1,000 mg to 800/600 mg could reduce the proportions of grade 2 anemia by about half. The resulting model framework will aid the development of dosing strategies that minimize the incidence of anemia in treatment regimens that include ribavirin.

VDR gene polymorphisms impact on anemia at 2 weeks of anti-HCV therapy: a possible mechanism for early RBV-induced anemia

OBJECTIVES

Vitamin D receptors (VDR) bind calcitriol and modulate several physiological systems through genomic and nongenomic pathways. Calcitriol stimulates store-operated channels Ca²⁺ influx by translocation of the caveolar VDR to the plasma membrane. Intracellular Ca²⁺ levels in erythrocytes control biophysical properties and an increase in its concentration can deregulate membrane composition, cell volume, glycolytic enzymes regulation, redox state, and cell clearance.We evaluated the role of single nucleotide polymorphisms in ITPA, CYP27B1, CYP24A1, and VDR genes in the prediction of ribavirin-induced anemia in HCV-1/2/3/4 patients at 2 and 4 weeks of treatment.

PATIENTS AND METHODS

Two hundred and twenty-five patients treated with ribavirin and pegylated interferon-α were genotyped by real-time PCR.

RESULTS

BMI at baseline more than 30 kg/m² [P=0.013, odds ratio (OR): 10.95, 95% confidence interval (CI): 1.66-74.21], alanine aminotransferase at baseline more than 37 IU/l (P=0.020, OR: 0.26, 95% CI: 0.09-0.81), and the VDR BsmI AA profile (P=0.003, OR: 5.09, 95% CI: 1.72-15.05) were anemia-predictive factors at 2 weeks of therapy. At week 4, the ITPA rs6051702 AC/CC profile (P=0.001, OR: 0.19, 95% CI: 0.07-0.51) was the only factor that could predict this side effect.

CONCLUSION

The BsmI AA genotype is a predictive factor of 2-week anemia and it could be related to a VDR-enhanced activity, and thus an increased calcium influx, resulting in the deregulation of the Ca²⁺-dependent signaling, which can lead to erythrocytes hemolysis. This rapid mechanism could be responsible for the development of early anemia.These results indicate for the first time the strong, significant, and independent role of VDR in the early development of ribavirin-induced anemia and confirm the ITPA function in the prediction of anemia at week 4.

Ribavirin concentration determines treatment success of first-generation DAA-based chronic HCV therapy

BACKGROUND

Monitoring ribavirin concentrations during hepatitis C treatment with dual therapy can help optimize treatment response and minimize anaemia. A defined therapeutic range for ribavirin during direct-acting antiviral-based therapies is lacking. This analysis explores whether a therapeutic range for ribavirin concentrations can be defined in patients treated with boceprevir- or telaprevir-based triple therapies.

METHODS

Treatment-naive patients from ADVANCE, ILLUMINATE, OPTIMIZE and SPRINT-2, and treatment-experienced patients from RESPOND-2 were included. Multivariable logistic regression analyses were performed to evaluate whether ribavirin concentrations were an independent predictor of sustained virological response or anaemia. Optimal cutoff values and the percentage of patients within the proposed therapeutic range were determined, along with the associated chance of response.

RESULTS

Overall, 1,502 patients were included. In both regimens, ribavirin concentrations were significantly associated with anaemia (haemoglobin level <10 g/dl) at all time points (1.75 < odds ratio [OR] <2.45) and sustained virological response was associated with ribavirin concentrations at week 8 (OR=1.43 for telaprevir and 1.78 for boceprevir). A therapeutic range for ribavirin at week 8 of 2.2-3.5 mg/l was defined for telaprevir treatment. Of the 48% of patients with a concentration within this range, 81% achieved sustained virological response and only 5.1% reported anaemia. For boceprevir treatment, the week 8 optimal range was defined as 2.2-3.6 mg/l and 50% of patients had a concentration within this range, of whom 69% achieved sustained virological response and 46% developed anaemia.

CONCLUSIONS

We established the therapeutic range for ribavirin in boceprevir- and telaprevir-based therapy that balances safety and efficacy.

UPLC-MS/MS method with automated on-line SPE for the isomer-specific quantification of the first-generation anti-HCV protease inhibitors in peripheral blood mononuclear cells

HCV infection affects over 170 million people worldwide. The current standard for treatment of genotype 1 infection is the association of the first generation protease inhibitors boceprevir or telaprevir to ribavirin and peginterferon α. Although the response rate has been improved with these new drugs, some pharmacokinetic/pharmacodinamic issues emerged in the past years. To date, some analytical methods are available for the quantification of these drugs in plasma; however, the real active concentrations of the two drugs are those in hepatocytes. Being the withdrawal of hepatocytes too invasive, in this work we aimed to develop and validate a chromatographic method coupled with tandem mass spectrometry capable of quantifying boceprevir and telaprevir isomers in peripheral blood mononuclear cells, used as an "in-vivo" cellular model of compartmentalization. The method used an on-line solid phase extraction protocol based on the new OSM(®) platform and was fully validated following FDA guidelines. This method showed mean intra- and inter-day inaccuracy and imprecision both lower than 15%, high and stable recovery and contained matrix effect, with a run time of 6min, comprehensive of SPE extraction. The method was then applied on 35 real samples from patients treated with boceprevir or telaprevir, with good analytical performances, thus assessing its eligibility for a possible future routine use. Peculiar pharmacokinetic data have been observed, suggesting the usefulness of investigating intracellular pharmacokinetics of these drugs. Further studies will be required to test the correlation of intracellular concentrations with effectiveness and toxicity of triple therapy.

Comparative safety study on severe anemia by simeprevir versus telaprevir-based triple therapy for chronic hepatitis C

BACKGROUND AND AIM

The addition of hepatitis C virus (HCV) NS3/4A protease inhibitors to the pegylated interferon (PEG-IFN) α and ribavirin combination regimen (triple therapy) has dramatically improved treatment outcome. Unfortunately, anemia remains a common adverse effect. This study was done to compare the development of severe anemia during simeprevir- or telaprevir-based triple therapy.

METHODS

This retrospective multicenter study consisted of 837 consecutive Japanese HCV genotype 1 patients treated in a real-world clinical setting, 811 of whom were enrolled (simeprevir 281, telaprevir 530). The inosine triphosphate pyrophosphatase (ITPA) genotype at rs1127354 was determined for all studied patients. Logistic regression was done after propensity score matching to assess the risk of development of severe anemia.

RESULTS

Propensity score matching of the entire study population yielded 266 matched pairs. Severe anemia (nadir hemoglobin < 9.0 g/dL) was developed during the treatment period by 81 (30.5%) and 144 (54.1%) patients treated with simeprevir and telaprevir, respectively. Treatment with simeprevir was independently associated with a lower risk of severe anemia (odds ratio 0.25, 95% confidence interval 0.16-0.38, P < 0.0001). Moreover, ITPA genotype, age, hemoglobin level, and estimated glomerular filtration rate at baseline were also independent factors associated with the development of severe anemia.

CONCLUSIONS

Patients treated with simeprevir-based triple therapy have a lower risk of the development of severe anemia than those treated with telaprevir. Moreover, ITPA genotype and age may be useful for individualizing treatment to reduce the risk of anemia-related adverse effects.

Pharmacokinetic interactions between telaprevir and antiretroviral drugs in HIV/HCV-coinfected patients with advanced liver fibrosis and prior HCV non-responders

Complex drug-drug interactions have been reported with concurrent administration of telaprevir (TVR) and human immunodeficiency virus (HIV) protease inhibitors (PIs), leading to relevant limitations of the therapeutic options for patients coinfected with hepatitis C virus (HCV) and HIV. However, little is known about the pharmacokinetics and drug interactions between TVR and antiretrovirals in HIV/HCV-coinfected patients with advanced liver fibrosis. Here we report the pharmacokinetics of TVR and antiretrovirals in a cohort of HIV/HCV genotype 1-coinfected patients with advanced liver fibrosis treated with TVR-based triple anti-HCV therapy. No significant differences were observed in the pharmacokinetics of atazanavir, amprenavir or tenofovir at baseline and at Day 15 of TVR, whereas the AUC0-4h of darunavir was 36% lower in the presence of TVR (AUC0-4h 15007ngh/mL and 9563ngh/mL at baseline and at Day 15 of TVR administration, respectively). Noteworthy, the AUC0-4h, Cmin and Cmax of raltegravir were reduced by 61%, 50% and 64%, respectively. However, none of the patient's plasma levels of tenofovir, atazanavir, amprenavir or raltegravir declined below their minimum effective concentrations even in association with TVR, and no HIV treatment failure occurred. A non-significant trend for lower TVR exposure was seen in patients concomitantly given amprenavir versus those given atazanavir (AUC0-4h, 9840ngh/mL and 13345ngh/mL, respectively). In conclusion, this study highlighted the feasibility of maintaining the current antiretroviral regimen in HIV/HCV-coinfected patients, even when significant interactions with TVR are predictable, whenever a change of HIV PIs is not deemed appropriate.