Assessment of the pharmacokinetic interaction between eltrombopag and lopinavir-ritonavir in healthy adult subjects. Antimicrob Agents Chemother. 2012;56:2846-2851. [PMID: 22391553 DOI: 10.1128/AAC.05214-11]

Simultaneous analysis of avatrombopag, eltrombopag, and hetrombopag in human plasma by UPLC-MS/MS for therapeutic drug monitoring

Avatrombopag, eltrombopag, and hetrombopag are three oral thrombopoietin receptor agonists used to treat thrombocytopenia. To investigate the pharmacokinetic properties, a fast and robust UPLC-MS/MS method was developed and validated for simultaneous determination of avatrombopag, eltrombopag, and hetrombopag in human plasma. Chromatographically separation was achieved on an Acquity BEH C18 column using a gradient elution of methanol-water (20:80, v/v) and acetonitrile containing 0.1% formic acid at a flow rate of 0.4 mL/min within 4.5 min. The linearity was assessed over the range of 7.5-1500 ng/mL for avatrombopag, 50-10,000 ng/mL for eltrombopag, and 5-1000 ng/mL for hetrombopag. This method was validated with adequate results in terms of selectivity, precision (intra- and inter-day CV from 4.2% to 12.2%), accuracy (RE from -6.6% to 7.5%), dilution integrity, carryover, recovery, matrix effects, as well as stability of the analytes under various conditions. The developed approach has been successfully applied to the therapeutic drug monitoring of avatrombopag, eltrombopag, and hetrombopag in patients with immune thrombocytopenia.

Stability-Indicating RP-HPLC Method Development and Validation for Eltrombopag Olamine in the Presence of Impurities and Degradation Products. Robustness by Design of Expert Software

BACKGROUND

A simple and reliable HPLC method for determining impurities in eltrombopag olamine (ELO) film-coated tablets is not available. At the same time, there is no official monograph reported. The proposed research is targeted at the development of a stability-indicating method for determining impurities in ELO film-coated tablets and drug substances.

OBJECTIVE

To develop and validate a simple and effective HPLC method for determining impurities in ELO film-coated tablets and drug substances.

METHODS

All the impurities were separated using a reverse phase (RP)-HPLC system equipped with a Zorbax SB-Phenyl 150 mm × 4.6 mm, 3.5 µm, column with UV detection at 230 nm and a flow rate of 1.2 mL/min. The column temperature was maintained at 45°C.

RESULTS

The proposed method was validated as per current regulatory guidelines. The coefficient of correlation was found to be >0.999 for all impurities. The LOD and LOQ for ELO and all specified impurities were determined. The precision and accuracy were obtained for ELO and its related impurities. Intra- and inter-day RSD values were between 1.22 and 2.04%, and impurity recovery varied between 93.80 and 103.69%. The stability of standard and sample solutions was established for 24 h.

CONCLUSIONS

As per recent guidelines, a stability-indicating method has been developed to determine the impurities in ELO film-coated tablets and drug substances. QbD-based robustness was performed and proved that the method was robust.

HIGHLIGHTS

The proposed article is the first RP-HPLC method for determining impurities in ELO film-coated tablets and drug substances. The quality by design (QbD) concept was utilized to verify the method performance.

Pharmacokinetics of Eltrombopag in Healthy Chinese Subjects and Effect of Sex and Genetic Polymorphism on its Pharmacokinetic and Pharmacodynamic Variability

BACKGROUND AND OBJECTIVE

Eltrombopag is the first oral, small-molecule, non-peptide thrombopoietin receptor agonist for the treatment of idiopathic thrombocytopenic purpura. This study investigated the pharmacokinetics of eltrombopag in healthy Chinese subjects and evaluated the effect of sex and genetic polymorphisms on its variability.

METHODS

Forty-eight healthy subjects were administered a single dose of eltrombopag (25 mg). Plasma concentrations of eltrombopag were determined using a validated liquid chromatography-tandem mass spectrometry method, and platelet counts were determined by blood tests. CYP1A2 rs762551, CYP2C8*3 rs10509681, CYP2C8*3 rs11572080, UGT1A1 rs887829, UGT1A3 rs3806596, and BCRP rs2231142 polymorphisms were genotyped by Sanger sequencing. A back-propagation artificial neural network (BP-ANN) model was constructed to predict pharmacokinetics based on physiological factors and genetic polymorphism data.

RESULTS

Compared with male subjects, female subjects who received a single 25-mg dose of eltrombopag exhibited a significantly increased mean maximum plasma concentration (C_max) and significantly decreased apparent clearance. Additionally, CYP1A2 rs762551 C>A single nucleotide polymorphism influenced distribution and elimination. C-allele carriers exhibited 30% higher systemic exposure and 20% lower apparent clearance compared with homozygous A-allele carriers. Mean percentage increases in platelet counts from baseline to Day 5 were 9.38% and 17.06% in male and female subjects, respectively. The BP-ANN model had a high goodness-of-fit index and good coherence between predicted and measured concentrations (R = 0.98979).

CONCLUSION

Sex and CYP1A2 rs762551 C>A were associated with the pharmacokinetic variability of eltrombopag in healthy Chinese subjects. Females exhibited a better platelet-elevating effect compared with males administered the same dosage. The developed BP-ANN model based on physiological factors and genetic polymorphism data could be promising for applications in pharmacokinetic studies.

TRIAL REGISTRATIONS

https://www.Chinadrugtrials.org.cn CTR20190898.

Drug interactions: a review of the unseen danger of experimental COVID-19 therapies

As global health services respond to the coronavirus pandemic, many prescribers are turning to experimental drugs. This review aims to assess the risk of drug-drug interactions in the severely ill COVID-19 patient. Experimental therapies were identified by searching ClinicalTrials.gov for 'COVID-19', '2019-nCoV', '2019 novel coronavirus' and 'SARS-CoV-2'. The last search was performed on 30 June 2020. Herbal medicines, blood-derived products and in vitro studies were excluded. We identified comorbidities by searching PubMed for the MeSH terms 'COVID-19', 'Comorbidity' and 'Epidemiological Factors'. Potential drug-drug interactions were evaluated according to known pharmacokinetics, overlapping toxicities and QT risk. Drug-drug interactions were graded GREEN and YELLOW: no clinically significant interaction; AMBER: caution; RED: serious risk. A total of 2378 records were retrieved from ClinicalTrials.gov, which yielded 249 drugs that met inclusion criteria. Thirteen primary compounds were screened against 512 comedications. A full database of these interactions is available at www.covid19-druginteractions.org. Experimental therapies for COVID-19 present a risk of drug-drug interactions, with lopinavir/ritonavir (10% RED, 41% AMBER; mainly a perpetrator of pharmacokinetic interactions but also risk of QT prolongation particularly when given with concomitant drugs that can prolong QT), chloroquine and hydroxychloroquine (both 7% RED and 27% AMBER, victims of some interactions due to metabolic profile but also perpetrators of QT prolongation) posing the greatest risk. With management, these risks can be mitigated. We have published a drug-drug interaction resource to facilitate medication review for the critically ill patient.

Incidence of Adverse Drug Reactions in COVID-19 Patients in China: An Active Monitoring Study by Hospital Pharmacovigilance System

To evaluate the incidence, type, and risk factors associated with adverse drug reactions (ADRs) among patients with coronavirus disease 2019 (COVID-19) by Hospital Pharmacovigilance System (CHPS). A retrospective analysis was performed on 217 patients with COVID-19 admitted to the First Hospital of Changsha in China, from January 17, 2020, to February 29, 2020. The active monitoring model in CHPS was used to detect ADR signals of the hospital information system. The risk factors for the ADRs were classified using the World Health Organization-Uppsala Monitoring Centre (WHO-UMC) system. Univariate and multivariate logistic regressions were carried out to analyze the risk factors of ADRs. Our results showed that the prevalence of ADRs was 37.8% in the patients, which was predominated by drug-induced gastrointestinal disorders and liver system disorders (23.0% vs. 13.8%). The ADR could be explained by the use of lopinavir/ ritonavir and umifenovir by 63.8% and 18.1%, respectively. There were 96.8% of ADRs that occurred within 14 days of hospitalization. Multivariable analysis showed that length of stay (odds ratio (OR): 2.02; 95% confidence interval (CI) 1.03-3.96; P = 0.04), number of drugs used in the hospital (OR: 3.17; 95% CI 1.60-6.27; P = 0.001) and underlying basic diseases (OR: 2.07; 95% CI 1.02-4.23; P = 0.04) were independent risk factor for ADRs in the patients. Together, the incidence of ADRs was significantly high during the treatment period. Moreover, the active monitoring of the CHPS system reflected ADRs during COVID-19 treatment in the real world, which provided reference for safe medication in the clinic.

Identification of Modulators of HIV-1 Proviral Transcription from a Library of FDA-Approved Pharmaceuticals

Human immunodeficiency virus 1 (HIV-1) is the most prevalent human retrovirus. Recent data show that 34 million people are living with HIV-1 worldwide. HIV-1 infections can lead to AIDS which still causes nearly 20,000 deaths annually in the USA alone. As this retrovirus leads to high morbidity and mortality conditions, more effective therapeutic regimens must be developed to treat these viral infections. A key target for intervention for which there are no current FDA-approved modulators is at the point of proviral transcription. One successful method for identifying novel therapeutics for treating infectious diseases is the repurposing of pharmaceuticals that are approved by the FDA for alternate indications. Major benefits of using FDA-approved drugs include the fact that the compounds have well established toxicity profiles, approved manufacturing processes, and immediate commercial availability to the patients. Here, we demonstrate that pharmaceuticals previously approved for other indications can be utilized to either activate or inhibit HIV-1 proviral transcription. Specifically, we found febuxostat, eltrombopag, and resveratrol to be activators of HIV-1 transcription, while mycophenolate was our lead inhibitor of HIV-1 transcription. Additionally, we observed that the infected cells of lymphoid and myeloid lineage responded differently to our lead transcriptional modulators. Finally, we demonstrated that the use of a multi-dose regimen allowed for enhanced activation with our transcriptional activators.

Prediction of Clinical Transporter-Mediated Drug-Drug Interactions via Comeasurement of Pitavastatin and Eltrombopag in Human Hepatocyte Models

A structurally identifiable micro‐rate constant mechanistic model was used to describe the interaction between pitavastatin and eltrombopag, with improved goodness‐of‐fit values through comeasurement of pitavastatin and eltrombopag. Transporter association and dissociation rate constants and passive rates out of the cell were similar between pitavastatin and eltrombopag. Translocation into the cell through transporter‐mediated uptake was six times greater for pitavastatin, leading to pronounced inhibition of pitavastatin uptake by eltrombopag. The passive rate into the cell was 91 times smaller for pitavastatin compared with eltrombopag. A semimechanistic physiologically‐based pharmacokinetic (PBPK) model was developed to evaluate the potential for clinical drug–drug interactions (DDIs). The PBPK model predicted a twofold increase in the pitavastatin peak blood concentration and area under the concentration‐time curve in the presence of eltrombopag in simulated healthy volunteers. The use of structural identifiability supporting experimental design combined with robust micro‐rate constant parameter estimates and a semimechanistic PBPK model gave more informed predictions of transporter‐mediated DDIs.

Effect of cyclosporine coadministration on the pharmacokinetics of eltrombopag in healthy volunteers

PURPOSE

Eltrombopag is indicated in patients with severe aplastic anemia (SAA) refractory to prior immunosuppressive therapy. The combination of eltrombopag and immunosuppressive therapy (such as cyclosporine) is currently being evaluated in patients with treatment-naive SAA. Cyclosporine is a human breast cancer resistance protein (BCRP) inhibitor, and can potentially alter plasma exposure to eltrombopag, a BCRP substrate. This phase 1, open-label, randomized, 3-period, crossover study evaluated the effect of cyclosporine on the pharmacokinetics of eltrombopag in healthy adults.

METHODS

Thirty-nine subjects were randomized to either single dose of eltrombopag 50 mg, cyclosporine 200 mg + eltrombopag 50 mg or cyclosporine 600 mg + eltrombopag 50 mg treatment groups. Eltrombopag pharmacokinetic parameters (C_max, t_max, AUC_last, AUC_inf, %AUC_ex, t_1/2, and CL/F) were determined using noncompartmental methods.

RESULTS

Geometric mean AUC_inf, AUC_last, and C_max, were decreased by 18, 20, and 25%, respectively, for cyclosporine 200 mg + eltrombopag and by 24, 22, and 39%, respectively, for cyclosporine 600 mg + eltrombopag groups compared to the eltrombopag alone group. The median t_max was prolonged by ~ 1 h in both coadministration treatments. The geometric mean t_1/2 was ≈ 21, ≈ 24, and ≈ 26 h, respectively, in cyclosporine 200 mg + eltrombopag, cyclosporine 600 mg + eltrombopag and eltrombopag alone groups. All the treatments were safe and well-tolerated. No serious adverse event or death was reported during the study.

CONCLUSION

These changes in exposure were not considered clinically meaningful as the dose of eltrombopag is adjusted using within-patient dose titration based on platelet counts.

Prediction of area under the concentration-time curve for lopinavir from peak or trough lopinavir concentrations in patients receiving lopinavir-ritonavir therapy

PURPOSE

A "single time point" strategy for predicting the area under the concentration-time curve (AUC) for lopinavir in patients receiving ritonavir-boosted lopinavir therapy was investigated.

METHODS

Linear regression equations describing the relationships of lopinavir peak and trough concentrations to lopinavir AUC values were established using pharmacokinetic data from published studies of patients or healthy subjects receiving lopinavir and ritonavir at standard dosages. The resulting "trough-AUC model" and "peak-AUC model" were used to predict lopinavir AUC values in the evaluated study populations (total n = 479); those values were then compared with reported AUC values.

RESULTS

Lopinavir peak or trough concentrations were strongly correlated with lopinavir AUC values (r = 0.9947 and r = 0.9541, respectively). For about 94% of calculations using the peak-AUC model and 87% of calculations using the trough-AUC model, differences between predicted and observed AUC values were in the range of 0.76-1.5 fold; the associated r values were 0.9514 (p < 0.001) and 0.9345 (p < 0.001), respectively. The mean absolute predictive error was less than 6% with the use of either the peak-AUC model or the trough-AUC model, with corresponding values for root-mean-square error of 17.6% and 23.5%, respectively.

CONCLUSION

Equations incorporating lopinavir peak and trough concentrations were found to satisfactorily predict lopinavir AUC values in data sets describing patients receiving lopinavir with ritonavir boosting. Variability in predictions was higher with use of the trough-AUC model.

Eltrombopag: a review of its use in the treatment of thrombocytopenia in patients with chronic hepatitis C

Eltrombopag (Revolade(®); Promacta(®)) is an orally bioavailable, small-molecule, thrombopoietin receptor agonist that selectively binds to thrombopoietin receptors on megakaryocyte precursors and megakaryocytes leading to increased platelet production. It is approved in a number of countries for the treatment of thrombocytopenia, including adult patients with chronic hepatitis C virus (HCV) infection to allow for the initiation and maintenance of peginterferon-based therapy, which is the focus of this review. In two, well-designed, randomized controlled trials in adults with chronic HCV infection and thrombocytopenia (ENABLE-1 and ENABLE-2), eltrombopag increased platelet counts to sufficient levels to allow for the initiation of peginterferon-based antiviral therapy in 95 % of patients whose baseline platelet counts would have made them ineligible or marginal candidates for peginterferon therapy. Moreover, a significantly higher proportion of eltrombopag recipients than placebo recipients achieved a sustained virological response (primary endpoint) 24 weeks after the completion of antiviral therapy. Of note, the additional benefit over placebo was relatively small (<10 %). Compared with placebo, eltrombopag was associated with fewer patients discontinuing antiviral therapy early and a numerically greater proportion of patients not requiring antiviral dose reduction. Oral eltrombopag had an acceptable tolerability profile; however, there is an increased risk of adverse events, including potentially fatal hepatic decompensation and thromboembolic events. Eltrombopag provides a new treatment option for thrombocytopenia in patients with chronic HCV infection to allow for optimal antiviral therapy.

Eltrombopag in chronic hepatitis C

Chronic hepatitis C is a public health problem worldwide. Unfortunately, not all patients may benefit from antiviral therapy due to thrombocytopenia. Its causes are represented by portal hypertension and platelet sequestration in the spleen, decreased serum levels or activity of thrombopoietin, the bone marrow suppression induced by hepatitis C virus and a possible adverse effect of interferon. Thrombopoietin receptor analogs may contribute to increase platelet counts in these patients. Eltrombopag binds to another region of the thrombopoietin receptor compared to endogenous thrombopoietin and stimulates the proliferation and maturation of megakaryocytes and the platelet production in a dose-dependent manner. Eltrombopag has proven its effectiveness for the treatment of patients with primary immune thrombocytopenia. Its indication for other hemopathies or situations (like thrombocytopenia secondary to chemo- or radiotherapy, acute leukemia, myelodysplastic syndroms, acquired and hereditary bone marrow failure, and platelet donors) is under study. Eltrombopag may be particularly useful in patients with advanced chronic hepatitis or liver cirrhosis who require antiviral treatment. We present a minireview on the results of treatment with eltrombopag in patients chronically infected with hepatitis C virus, highlighting the benefits and mentioning possible adverse effects. In some studies eltrombopag increased the number of virological responses after clasical antiviral treatment of patients with chronic hepatitis C and reduced the transfusional requirements of those who had to be subjected to invasive surgery. Eltrombopag is a solution for many of these patients, which allows them receiving antiviral therapy and sometimes getting a sustained virological response, but they must be well monitored to prevent possible thromboembolic or bone marrow complications or liver failure occurrence.

Co-administration of a commonly used Zimbabwean herbal treatment (African potato) does not alter the pharmacokinetics of lopinavir/ritonavir

OBJECTIVE

African potato (Hypoxis obtusa) is commonly used in Sub-Saharan Africa as a complementary herbal remedy for HIV-infected patients. It is unknown whether or not co-administration of African potato alters the pharmacokinetics of protease inhibitor antiretrovirals. The objective of this study was to investigate the impact of the African potato on the steady-state pharmacokinetics of ritonavir-boosted lopinavir (LPV/r).

METHODS

Sixteen adult volunteers were administered LPV/r 400/100 mg twice a day for 14 days, followed by concomitant administration with African potato given once daily for 7 days. Lopinavir plasma exposure as estimated by the area under the concentration-time curve over the 12-h dosing interval (AUC(0-12h), AUCτ) was determined on day 14 and again on day 21. Lopinavir in plasma was analyzed using a validated liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. Steady-state AUCτ and the maximum concentration following dose administration (C(max)) were determined using non-compartmental methods using WinNonlin Professional version 5.2.1. Statistical analyses were performed using Stata version 12.1.

RESULTS

Co-administration of African potato was not associated with any change in lopinavir AUCτ, C(max), or C(trough).

CONCLUSIONS

African potato when taken concomitantly with LPV/r is well-tolerated and not associated with clinically significant changes in lopinavir pharmacokinetics.