Pharmacogenetics of tenofovir drug transporters in the context of HBV: Is there an impact?

BACKGROUND: Current treatments for chronic hepatitis B management include orally administered nucleos(t)ide analogues, such as tenofovir (TDF), which is an acyclic adenine nucleotide analogue used both in HBV and human immune deficiency virus (HIV). The course of HBV infection is mainly dependent on viral factors, such as HBV genotypes, immunological features and host genetic variables, but a few data are available in the context of HBV, in particular for polymorphisms of genes encoding proteins involved in drug metabolism and elimination. Consequently, the aim of this study was to evaluate the potential impact of genetic variants on TDF plasma and urine concentrations in patients with HBV, considering the role of HBV genotypes. METHODS: A retrospective cohort study at the Infectious Disease Unit of Amedeo di Savoia Hospital, Torino, Italy, was performed. Pharmacokinetic analyses were performed through liquidi chromatography, whereas pharmacogenetic analyses through real-time PCR. FINDINGS: Sixty - eight patients were analyzed: ABCC4 4976 C>T genetic variant showed an impact on urine TDF drug concentrations (p = 0.014). In addition, SLC22A6 453 AA was retained in the final regression multivariate model considering factors predicting plasma concentrations, while ABCC4 4976 TC/CC was the only predictor of urine concentrations in the univariate model. INTERPRETATION: In conclusion, this is the first study showing a potential impact of genetic variants on TDF plasma and urine concentrations in the HBV context, but further studies in different and larger cohorts of patients are required.

Data on compounding lopinavir and ritonavir suspension for non-cooperative COVID-19 patients.

The COVID-19 outbreak is now one of the most critical crises to manage for most of national healthcare systems in the world. The situation is complicated by the absence of vaccines and authorized pharmacological treatments, except for remdesivir. In this context, many medicaments, including different Ebola and HIV antivirals, are used off-label in the hospital wards as life-treating medicines for COVID-19 patients. Authorized medicaments manipulation is sometimes necessary because they are not always formulated to be administered to non-cooperative patients or they are in shortage. It is this the case of the fixed combination of lopinavir/ritonavir, which was extensively used in the first phase of the outbreak inducing a shortage of the oral solution available in the EU market. This work provides data on size distribution, osmolarity other than drug chemical stability of a lopinavir/ritonavir extemporaneous preparation made by using the solid dosage form (i.e., tablet) available on the market as drug source. The reported data indicate that such preparation is suitable to be delivered through a nasogastric tube, and enough stable for two weeks from the preparation at room temperature.

Data on the stability of darunavir/cobicistat suspension after tablet manipulation.

The COVID-19 outbreak is now one of the most critical crises to manage for most of the national healthcare systems in the world. In the absence of authorised pharmacological treatments, many antiretrovirals, including darunavir/cobicistat fixed combination, are used off-label in the hospital wards as life-treating medicines for COVID-19 patients. Unfortunately, for most of them, the drug products available on the market are not designed to be administered by a nasogastric tube to inpatients of intensive care units. Therefore, their manipulation, even if it can strongly affect the product quality, is necessary for the preparation of suspension to meet patients' need. In this situation, it is urgent to provide data and guidance to support hospital pharmacists and clinicians in their activity. The data in this article indicate that darunavir/cobicistat suspensions compounded by pharmacists using as active ingredient a commercially available tablet can be stable at least for one week.

Antiretroviral concentrations in the presence and absence of valproic acid.

OBJECTIVES: An unexpected drug-drug interaction has been recently reported between dolutegravir, an HIV integrase inhibitor, and valproic acid. Despite there being several potential underlying mechanisms, plasma protein displacement has been suggested. The aim of this study was to assess plasma concentrations of several antiretrovirals when administered with or without valproic acid. METHODS: We performed a therapeutic drug monitoring registry analysis and identified patients concomitantly taking antiretrovirals and valproic acid and without clinical affecting conditions or interacting drugs. RESULTS: One hundred and thirty-four patients were identified. Median (IQR) age and BMI were 49.7 years (45-56) and 23.4 kg/m2 (20.8-26.3) and 78 were male (58.2%). Despite small groups, we observed no major effect on antiretroviral exposure, even when considering highly protein-bound compounds (such as etravirine), with the exception of dolutegravir trough concentrations [median (IQR) = 132 ng/mL (62-227) in individuals on valproic acid versus 760 ng/mL (333-1407) in those not receiving valproic acid]. CONCLUSIONS: Valproic acid does not have a major effect on antiretrovirals other than dolutegravir. The mechanism of this unexpected drug-drug interaction may be the combination of protein displacement, reduced absorption and CYP3A4 induction.

Serum Trimethylamine-N-oxide Concentrations in People Living with HIV and the Effect of Probiotic Supplementation.

BACKGROUND: The incidence of cardiovascular disorders in people living with HIV (PLWH) is higher than that in non-infected individuals. Traditional and specific risk factors have been described but the role of the gut microbiota-dependent choline metabolite, trimethylamine-N-oxide (TMAO) is still unclear. METHODS: A cross-sectional analysis and a longitudinal analysis (with high-dose probiotic supplementation) were performed to measure serum TMAO concentrations through UHPLC-MS/MS. Stable outpatients living with HIV on highly active antiretroviral treatment with no major cardiovascular disease were enrolled. Non-parametric tests (bivariate and paired tests) and a multivariate linear regression analysis were used. RESULTS: A total of 175 participants were enrolled in the study. Median serum TMAO concentrations were 165 (103-273) ng/mL. An association with age, serum creatinine, number of antiretrovirals, multimorbidity and polypharmacy was observed; at linear logistic regression analysis, multimorbidity was the only independent predictor of TMAO concentrations. Carotid intima media thickness (IMT) was 0.85 (0.71-1.21) mm, with a trend towards higher TMAO concentrations observed in patients with IMT >0.9 mm (P=0.087). In the 25 participants who received probiotic supplementation, TMAO levels did not significantly change after 24 weeks (Wilcoxon paired P=0.220). CONCLUSION: Serum TMAO levels in PLWH were associated with multimorbidity, higher cardiovascular risk and subclinical atherosclerosis and were not affected by 6 months of high-dose probiotic supplementation.

Cerebrospinal fluid abacavir concentrations in HIV-positive patients following once-daily administration.

Abacavir is a widely used nucleotide reverse transcriptase inhibitor, for which cerebrospinal fluid (CSF) exposure has been previously assessed in twice-daily recipients. We studied abacavir CSF concentrations in 61 and nine HIV-positive patients taking abacavir once daily and twice daily, respectively. Patients on once-daily abacavir had higher plasma and CSF concentrations (96 vs. 22 ng ml-1 , P = 0.038 and 123 vs. 49 ng ml-1 , P = 0.038) but similar CSF-to-plasma ratios (0.8 vs. 0.5, P = 0.500). CSF abacavir concentrations were adequate in patients receiving once-daily treatment.

Role of CYP24A1, VDR and GC gene polymorphisms on deferasirox pharmacokinetics and clinical outcomes.

ß-Thalassemia patients develop deficiency in vitamin D absorption and liver hydroxylation, resulting in extremely low calcitriol levels. We explored the role of single-nucleotide polymorphisms (SNPs) involved in vitamin D metabolism, transport and activity on deferasirox pharmacokinetics and outcomes (effectiveness trough levels (Ctrough) and the area under the curve (AUC) cutoffs of 20 µg ml-1 and 360 µg ml-1 h-1, respectively; nonresponse AUC limit of 250 µg ml-1 h-1). Ninety-nine ß-thalassemic patients were enrolled. Drug plasma Ctrough and AUC were measured by the high-performance liquid chromatography system coupled with an ultraviolet determination method. Allelic discrimination for VDR, CYP24A1, CYP27B1 and GC gene SNPs was performed by real-time PCR. CYP24A1 22776 TT significantly influenced Cmin and negatively predicted it in regression analysis. CYP24A1 3999 CC was associated with Ctrough and Cmin and was a negative predictor of Tmax, whereas CYP24A1 8620 GG seemed to have a role in Ctrough, AUC, t1/2 and Cmin, and was an AUC negative predictor factor. Considering treatment outcome, Cdx2 and GC 1296 were retained in regression analysis as AUC efficacy cutoff negative predictors.

Efficacy of sofosbuvir and ledipasvir in an HCV+ gastro-resected patient.

WHAT IS KNOWN AND OBJECTIVE: The second-generation direct-acting antivirals represented the first major turning point for the eradication of HCV infection in almost all settings of patients. However, no data were available on use in gastro-resected patients. CASE DESCRIPTION: We report on a gastrectomized patient with chronic hepatitis C infection. She was treated with sofosbuvir and ledipasvir (SOF/LDV) for 12 weeks, with measurement of blood levels of the drugs. She obtained sustained virological response at week 12 and 24 without dose adjustment. WHAT IS NEW AND CONCLUSION: This case report can provide information useful for clinical practice in this set of patients and can open new perspectives in evaluating actual SOF/LDV bioavailability.

Treatment with direct-acting antiviral agents of hepatitis C virus infection in injecting drug users: A prospective study.

In this prospective study, we evaluated the effectiveness and tolerability of novel therapies against hepatitis C virus (HCV) in a cohort of PWID enrolled at our centre from April 2015 to July 2016. In this analysis, a total of 174 patients were included: eleven (6.3%) were treated with pegylated interferon (PEG-IFN) and ribavirin (RBV) containing regimens, 163 (93.7%) with IFN-free treatments. RBV has been used in 70 patients (40.2%); 59 (33.9%) patients were in opioid substitution therapy (OST) with methadone or buprenorphine. Overall, sustained virological response (SVR) has been observed in 162 subject (93.1%), breakthrough (BT) in three (1.7%), relapse in one (0.6%) and dropout in eight (4.6%). Treatment was interrupted for clinical conditions in seven patients: six (3.4%) had hepatic decompensation and one died for hepatocellular carcinoma (HCC). In multivariate analysis, predictive factors of treatment failure were as follows: albumin level below 3 g/dL (OR=7.190; 95% IC=1.236-41.837; P<.001), MELD score >10 (OR=5.886; 95% IC=1.411-35.994; P<.001) and years of HCV infection >20 (OR=1.286; 95% IC=0.556-9.455; P=.016). In conclusion, treatment with DAAs was effective and well tolerated in PWID; cirrhotic subjects with MELD > 10 and albumin low level showed a higher risk of developing serious adverse events and treatment failure.

Relationship between the early boceprevir-S isomer plasma concentrations and the onset of breakthrough during HCV genotype 1 triple therapy.

In a prospective cohort of 18 patients treated with boceprevir, we examined the role of boceprevir plasma concentration at the onset of breakthrough during the treatment. Nine patients experienced breakthrough during therapy. The resistance patterns were as follows: S122S/R, I132V, T54A/I132V, V156S/I170A, V36M/T54S/R155K, V36M/R155K and T54/R155K. Boceprevir-S isomer (SCH 534128) median concentration in patients with breakthrough was 48.3 ng/mL (interquartile range 43-58 ng/mL); in others, it was significantly (p 0.019) higher: 151 ng/mL. Low boceprevir plasma concentration can lead to virologic resistance; therapeutic drug monitoring should be used to prevent the onset of viral breakthrough during triple-regimen therapy with boceprevir.

Role of CYP27B1+2838 promoter polymorphism in the treatment of chronic hepatitis B HBeAg negative with PEG-interferon.

In HBV-infected patients, the vitamin D deficiency has been related to chronic liver diseases, progression of hepatic fibrosis and poor response to the treatment. The CYP27B1 gene, which encodes the 1-α-hidroxylase and involved in the 1,25-dihydroxyvitamin D synthesis, was recently associated to type-1 diabetes, autoimmune disorders and treatment response in HCV. Then, we aimed to investigate the role of CYP27B1 polymorphisms in HBV treatment with PEG-IFN. We retrospectively enrolled 190 patients with chronic hepatitis B HBeAg negative treated for 48 weeks with PEG-IFN α-2a. We examined the role of rs4646536 CYP27B1 SNP (CYP27B1+2838) according to virological and serological response. Our results showed that the TT genotype of CYP27B1+2838 was significantly prevalent in patients with end-of-therapy virological response (37.6%) vs CT/CC (9.4%) (P < 0.001). Virological relapse was prevalent in patients with CT/CC genotype (12.6%) vs TT genotype (2.1%) (P < 0.001). TT genotype was also related to HBsAg loss (P = 0.004) and anti-HBs appearance (P = 0.002). In the multivariate analysis, the TT genotype resulted to be a good positive predictor of sustained virological response (OR = 5.632, IC = 1.938-16.368, P = 0.001) and serological response (OR = 6.161, IC = 1.856-20.457, P = 0.003). The CYP27B1+2838 polymorphism may be useful as pretreatment factor to selection of patients with higher probability of response to therapy.

Significant early higher ribavirin plasma concentrations in patients receiving a triple therapy with pegylated interferon, ribavirin and telaprevir.

The new standard of care for treatment for infection with genotype 1a/b of HCV now is the combination of telaprevir (TLV) with ribavirin (RBV) and pegylated interferon (Peg-IFN). Although this new therapy gives a higher response rate than the Peg-IFNα plus RBV treatment, a greatly higher rate of anaemia onset has been reported in all clinical trials. Because haemolysis is a typical concentration-dependent side effect of RBV, modulated by ITPA gene polymorphisms, we aimed to compare the early RBV plasma exposure of nine patients after 2 weeks of treatment with triple therapy with RBV concentrations of 187 patients treated with RBV and Peg-IFNα over the same time scale; this comparison was performed also stratifying patients according to ITPA polymorphism genotype and anaemia onset after 1 month of treatment. All TLV-treated patients had unfavourable ITPA genetic profile and developed anaemia. Moreover, both the rate of anaemia onset and the haemoglobin loss at 1 month were significantly higher in patients treated with TLV. This observation has been confirmed also in patients with the same ITPA genetic profile in double therapy. Strikingly, also early RBV plasma concentrations were significantly higher in patients treated with TLV. These unbiased results confirm the observations recently reported and suggest that the high rate of anaemia onset could be mainly due to the increased RBV exposure, probably caused by a 'boosting effect' by TLV. These data highlight the great importance of early therapeutic drug monitoring of RBV in the management of anaemia in the triple therapy.

Sequential therapy with entecavir and PEG-INF in patients affected by chronic hepatitis B and high levels of HBV-DNA with non-D genotypes.

Complete eradication of hepatitis B virus (HBV) is rarely achieved. Treatment options include currently available nucleos(t)ide analogues and pegylated interferon. The aim of our exploratory study was to assess the effectiveness of sequential therapy for chronic hepatitis B (CHB) vs the current standard of care. We evaluated an association with entecavir and pegylated interferon alfa-2a (PEG-IFN) in 20 patients with hepatitis B, high HBV viremia and genotypes A, B, C and E. Patients received entecavir alone for 12 weeks, then entecavir and PEG-IFN for 12 weeks, lastly PEG-IFN alone for 36 weeks. The results were compared with 20 patients (control group) treated in the past with 48 weeks of PEG-IFN monotherapy. Our results show that complete sustained virological response (SVR) and partial SVR were, respectively, 60% and 80% in the study group and 10% and 30% in the control group; anti-HBe seroconversion rate were 76.9% vs 15%, and anti-HBs seroconversion were 20% vs 0%, respectively. We found a correlation among different genotypes and virological and serological outcomes - genotype C has a better virological response, while genotype A had a better serological response, and E genotype had a poor response. These results show that a sequential approach is a promising strategy of treatment in patients with CHB and high viremia in comparison with PEG-IFN monotherapy. The E genotype seems to have the worse rate of response and requires other treatment strategies.

Hepatosplenic gammadelta T-cell lymphoma presenting with immune-mediated thrombocytopenia and hemolytic anemia (Evans' syndrome).

We describe an unusual case of hepatosplenic T-cell lymphoma in a 61-year-old man who presented with fever, hepatosplenomegaly, anemia, and thrombocytopenia. A spleen biopsy was consistent with T-cell lymphoma. Cytogenetic studies did not reveal chromosome abnormalities. Using the polymerase chain reaction approach, clonality of the T-cell receptor gamma-chain gene rearrangement could be demonstrated, while Southern blot analysis disclosed only a germline configuration of the T-cell receptor beta chain genes. Of interest, an immune-mediated mechanism was demonstrated and was most likely responsible for erythrocyte and platelet destruction; this is, therefore, the first report of gamma T-cell lymphoma in association with Evans' syndrome. Initial steroid treatment was efficacious in limiting autoimmunity but constitutional symptoms did not subside. Chemotherapy (MACOP-B) was successful in obtaining complete clinical remission. Finally, thrombocytopenia in gammadelta T-cell lymphoma patients should be routinely evaluated for platelet autoantibodies.

Lack of association between androgen receptor CAG polymorphism and familial breast/ovarian cancer.

The human androgen receptor (AR) gene contains a highly polymorphic CAG repeat in exon 1 that is inversely correlated with AR transcriptional activity in vitro. Several studies have shown that fewer CAG repeats are associated with an increased risk as well as more aggressive forms of prostate cancer. More recently, AR allele length was also inversely correlated with the histological grade of breast cancer, but no association was found between the AR-CAG polymorphism and the risk of either breast or ovary cancer. On the contrary, it was proposed that a longer CAG repeat sequence might be associated with an increased risk of breast cancer in BRCA1 mutation carriers, thus suggesting a different role of the AR-CAG polymorphism in sporadic and inherited breast cancers. With the intent of better understanding the role of the AR-CAG polymorphism as a cancer risk modifier, we defined the AR genotype of 151 patients (101 with breast and 50 with ovary cancer) belonging to high-risk breast/ovary cancer families. No difference in CAG repeat length was found between either breast and ovary cancer patients or age at diagnosis of both tumors. These results were also confirmed in a sub-group of 47 breast cancer cases, that either carried a BRCA gene mutation (11 cases) or were identified by very stringent operational criteria as hereditary breast cancers. Even though a substantially larger sample size would be required to reach conclusive evidence, our findings suggest that the AR-CAG polymorphism does not act as a modifier of tumor onset or tumor phenotype in breast/ovarian cancer families.

BRCA-1 and BRCA-2 mutations as prognostic factors in clinical practice and genetic counselling.

Women in general have a 10% risk of developing breast cancer and a 2-3% chance of ovarian cancer in their life-times. Mutations in BRCA-1 and BRCA-2 are present in only a small portion (5-10%) of all breast cancers. Carriers of mutations in these genes have a greater risk of cancer, especially before menopause in the case of BRCA-1 carriers. In addition, their risk of contralateral breast cancer is significantly higher than for the general population (4.2-53% vs. 2%). The grade of contralateral tumours in these patients is more aggressive. BRCA-2 hereditary breast cancer seems more heterogeneous than the BRCA-1 phenotype, and not clearly different from sporadic forms. However, since 20-30% of carriers of BRCA mutations never develop breast or ovarian cancer, there must be other 'risk modifiers'. Survival is better for carriers of hereditary ovarian cancer. Patients with these mutations are referred for genetic counselling, a complex process which includes: an informative dialogue between the proband and the geneticist, drawing up a family history, informed consent, evaluation of risk, genetic testing and possible involvement of healthy family members.