[Dramatic response to encorafenib plus binimetinib in a patient with leukemoid reaction from metastatic melanoma.] / Melanoma metastatico e reazione leucemoide: il ruolo della combo target.

Paraneoplastic leukemoid reaction (PLR) is an extremely rare condition in patients with melanoma and it is frequently associated with poor prognosis. BRAF gene mutational analysis represents the gold standard in patients with inoperable or metastatic melanoma as the possible presence of target mutations allows the use of the combination treatment with BRAF and MEK inhibitors. In this article, the case of a young woman with BRAF V600E mutated metastatic melanoma associated with PLR who received encorafenib and binimetinib is presented and discussed, with a focus on the relevant treatment response.

Response Rate and Molecular Correlates to Encorafenib and Binimetinib in BRAF-V600E Mutant High-Grade Glioma.

PURPOSE: Although fewer than 5% of high-grade gliomas (HGG) are BRAF-V600E mutated, these tumors are notable as BRAF-targeted therapy shows efficacy for some populations. The purpose of this study was to evaluate response to the combination of encorafenib with binimetinib in adults with recurrent BRAF-V600-mutated HGG. PATIENTS AND METHODS: In this phase 2, open-label, Adult Brain Tumor Consortium (ABTC) trial (NCT03973918), encorafenib and binimetinib were administered at their FDA-approved doses continuously in 28-day cycles. Eligible patients were required to have HGG or glioblastoma with a BRAF-V600E alteration that was recurrent following at least one line of therapy, including radiotherapy. RESULTS: Five patients enrolled between January 2020 and administrative termination in November 2021 (due to closure of the ABTC). Enrolled patients received treatment for 2 to 40 months; currently one patient remains on treatment. Centrally determined radiographic response rate was 60%, with one complete response and two partial responses. Methylation profiling revealed that all tumors cluster most closely with anaplastic pleomorphic xanthoastrocytoma (PXA). Transcriptional profile for MAPK-response signature was similar across all tumors at baseline and did not correlate with response in this small population. Circulating tumor DNA measured in plasma samples before treatment, during response, and upon progression showed feasibility of detection for the BRAF-V600E alteration. No new safety signal was detected. CONCLUSIONS: Encorafenib and binimetinib exhibit positive tumor responses in patients with recurrent BRAF-V600E mutant HGG in this small series, warranting therapeutic consideration. Although toxicity remains a concern for BRAF-targeted therapies, no new safety signal was observed in these patients.

Clinical Evaluation of the Effect of Encorafenib on Bupropion, Rosuvastatin, and Coproporphyrin I and Considerations for Statin Coadministration.

BACKGROUND AND OBJECTIVES: Encorafenib is a kinase inhibitor indicated for the treatment of patients with unresectable or metastatic melanoma or metastatic colorectal cancer, respectively, with selected BRAF V600 mutations. A clinical drug-drug interaction (DDI) study was designed to evaluate the effect of encorafenib on rosuvastatin, a sensitive substrate of OATP1B1/3 and breast cancer resistance protein (BCRP), and bupropion, a sensitive CYP2B6 substrate. Coproporphyrin I (CP-I), an endogenous substrate for OATP1B1, was measured in a separate study to deconvolute the mechanism of transporter DDI. METHODS: DDI study participants received a single oral dose of rosuvastatin (10 mg) and bupropion (75 mg) on days - 7, 1, and 14 and continuous doses of encorafenib (450 mg QD) and binimetinib (45 mg BID) starting on day 1. The CP-I data were collected from participants in a phase 3 study who received encorafenib (300 mg QD) and cetuximab (400 mg/m2 initial dose, then 250 mg/m2 QW). Pharmacokinetic and pharmacodynamic analysis was performed using noncompartmental and compartmental methods. RESULTS: Bupropion exposure was not increased, whereas rosuvastatin Cmax and area under the receiver operating characteristic curve (AUC) increased approximately 2.7 and 1.6-fold, respectively, following repeated doses of encorafenib and binimetinib. Increase in CP-I was minimal, suggesting that the primary effect of encorafenib on rosuvastatin is through BCRP. Categorization of statins on the basis of their metabolic and transporter profile suggests pravastatin would have the least potential for interaction when coadministered with encorafenib. CONCLUSION: The results from these clinical studies suggest that encorafenib does not cause clinically relevant CYP2B6 induction or inhibition but is an inhibitor of BCRP and may also inhibit OATP1B1/3 to a lesser extent. Based on these results, it may be necessary to consider switching statins or reducing statin dosage accordingly for coadministration with encorafenib. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT03864042, registered 6 March 2019.

Regression of liver fibrosis and hepatocellular carcinoma development after HCV eradication with oral antiviral agents.

We prospectively investigated the changes of liver stiffness (LS) and the occurrence of hepatocellular carcinoma (HCC) after hepatitis C virus (HCV) eradication using direct antiviral agents (DAA) over three years. LS measurement using transient elastography and serum fibrosis surrogate markers before treatment and at 48, 96, 144 weeks after starting direct-acting antivirals (DAA) according to the protocol were evaluated. Patients were also compared with historical cohort treated with pegylated interferon (peg-IFN). Sustained viral response (SVR) was observed in 95.8%. LS value in the patients achieving SVR significantly decreased over time (19.4 ± 12.9 kPa [baseline], 13.9 ± 9.1 kPa [48 weeks], 11.7 ± 8.2 kPa [96 weeks], 10.09 ± 6.23 [144 weeks], all p < 0.001). With matched analysis, the decrease in LS value was significantly larger in DAA group than peg-IFN group at both 48 weeks (29% vs. 9%) and 96 weeks (39% vs. 17%). The incidence of HCC was not significantly different between DAA and peg-IFN groups (5.5% vs. 5.4%) at 144 weeks. HCV eradication with DAA can lead to improvement of liver stiffness over time. The regression of fibrosis was greater in the group with DAA than peg-IFN.Clinical trials registration: ClinicalTrials.gov (NCT02865369).

Encorafenib plus binimetinib in patients with BRAFV600-mutant non-small cell lung cancer: phase II PHAROS study design.

BRAFV600 oncogenic driver mutations occur in 1-2% of non-small-cell lung cancers (NSCLCs) and have been shown to be a clinically relevant target. Preclinical/clinical evidence support the efficacy and safety of BRAF and MEK inhibitor combinations in patients with NSCLC with these mutations. We describe the design of PHAROS, an ongoing, open-label, single-arm, phase II trial evaluating the BRAF inhibitor encorafenib plus the MEK inhibitor binimetinib in patients with metastatic BRAFV600-mutant NSCLC, as first- or second-line treatment. The primary end point is objective response rate, based on independent radiologic review (per RECIST v1.1); secondary objectives evaluated additional efficacy end points and safety. Results from PHAROS will describe the antitumor activity/safety of encorafenib plus binimetinib in patients with metastatic BRAFV600-mutant NSCLC.

Plain language summary Some people with non-small-cell lung cancer (NSCLC) have changes in a gene called BRAF (known as 'gene mutations'). One common BRAF mutation is called 'V600'. Combinations of medicines that block proteins encoded by mutant BRAF and another gene called MEK can shrink tumors and slow their progression. We describe the design of PHAROS, a clinical trial investigating encorafenib (mutant BRAF inhibitor) combined with binimetinib (MEK inhibitor) in people with BRAF^V600-mutant NSCLC that had spread to other parts of the body ('metastatic disease'). People are monitored for side effects and to see if their tumor shrunk. PHAROS includes people treated with encorafenib plus binimetinib as their first treatment for metastatic disease, and people whose cancer progressed after previous anticancer therapy. Clinical trial registration: Clinicaltrials.gov (NCT03915951) and EudraCT (2019-000417-37).

Diagnostic approach to elucidate the efficacy and side effects of direct-acting antivirals in HCV infected patients.

INTRODUCTION: The conventional interferon therapy of hepatitis C virus has been substituted substantially with sofosbuvir and daclatasvir due to constraints in efficacy and tolerability. This study aimed diagnostically to monitor the effectiveness and side effects of direct-acting antivirals in the management of HCV infections. METHODOLOGY: This prospective study was conducted on HCV-infected patients treated with sofosbuvir and daclatasvir. Different serological, biochemical, hematological, and molecular techniques were used for the assessment of patients. Only treatment-naive patients aged ≥ 18 to 75 years received 12 weeks of treatment. The primary endpoint was a sustained virologic response with undetectable HCV RNA in the patients' serum at the end of the treatment. RESULTS: We identified 229 cases of confirmed HCV infections by PCR, 94.3% of which had genotype 3. The study population comprised 66% females and 34% males with a median age of 42.2 ± 10.6 SD. Ninety-three percent of the patients accomplished SVR at week 12. The combined therapy of SOF/DAC achieved the highest efficacy rate (92.6%) among the different HCV genotype 3 patients. A statistically significant relationship was observed between low baseline viral load (p < 0.001; 95% CI = 1.2-3.1) and HCV genotype 3 with minor side effects, including lethargy, headache, nausea, insomnia, diarrhea, and fever. CONCLUSIONS: HCV-infected patients can be treated well with an interferon-free SOF/DAC regimen, tolerated with generally mild adverse effects with a higher SVR.

Optimal Timing of Administration of Direct-acting Antivirals for Patients With Hepatitis C-associated Hepatocellular Carcinoma Undergoing Liver Transplantation.

OBJECTIVE: To investigate the optimal timing of direct acting antiviral (DAA) administration in patients with hepatitis C-associated hepatocellular carcinoma (HCC) undergoing liver transplantation (LT). SUMMARY OF BACKGROUND DATA: In patients with hepatitis C (HCV) associated HCC undergoing LT, the optimal timing of direct-acting antivirals (DAA) administration to achieve sustained virologic response (SVR) and improved oncologic outcomes remains a topic of much debate. METHODS: The United States HCC LT Consortium (2015-2019) was reviewed for patients with primary HCV-associated HCC who underwent LT and received DAA therapy at 20 institutions. Primary outcomes were SVR and HCC recurrence-free survival (RFS). RESULTS: Of 857 patients, 725 were within Milan criteria. SVR was associated with improved 5-year RFS (92% vs 77%, P < 0.01). Patients who received DAAs pre-LT, 0-3 months post-LT, and ≥3 months post-LT had SVR rates of 91%, 92%, and 82%, and 5-year RFS of 93%, 94%, and 87%, respectively. Among 427 HCV treatment-naïve patients (no previous interferon therapy), patients who achieved SVR with DAAs had improved 5-year RFS (93% vs 76%, P < 0.01). Patients who received DAAs pre-LT, 0-3 months post-LT, and ≥3 months post-LT had SVR rates of 91%, 93%, and 78% (P < 0.01) and 5-year RFS of 93%, 100%, and 83% (P = 0.01). CONCLUSIONS: The optimal timing of DAA therapy appears to be 0 to 3 months after LT for HCV-associated HCC, given increased rates of SVR and improved RFS. Delayed administration after transplant should be avoided. A prospective randomized controlled trial is warranted to validate these results.

Characterization of a Novel Hepatitis C Subtype, 6xj, and Its Consequences for Direct-Acting Antiviral Treatment in Yunnan, China.

Hepatitis C virus (HCV) has a high rate of genetic variability, with eight genotypes and 91 subtypes. The genetic diversity of HCV genotype 6 (HCV-6) is the highest with 31 subtypes, and this genotype is prevalent in Southeast Asia. In this study, we investigated 160 individuals with chronic hepatitis C in Yunnan Province, China. Using reverse transcription (RT)-PCR and Sanger sequencing, 147 cases were successfully amplified and genotyped as 3b (4.9%), 3a (19.73%), 6n (12.24%), 1b (7.48%), 2a (6.12%), 6a (2.04%), 1a (0.68%), 6v (0.68%), and 6xa (0.68%), with eight sequences remaining unclassified. Subsequently, the eight nearly full-length genomes were successfully amplified and analyzed. The eight complete coding sequences formed a phylogenetic group that was distinct from the previously assigned HCV-6 subtypes and clustered with two previously unnamed HCV-6 sequences. Furthermore, Simplot analysis showed no recombination and the p-distance was more than 15% in comparison to the 6a to 6xi subtypes. Taken together, we identified a new HCV-6 subtype, 6xj, which originated approximately in 1775 according to Bayesian analyses. Moreover, all eight individuals received follow-up assessments at 44 weeks from the beginning of their 12-week treatments of sofosbuvir/velpatasvir (after-treatment week 32). One case relapsed at after-treatment week 32. Next-generation sequencing (NGS) was conducted and showed that the treatment failure case had two suspected antiviral resistance mutations, NS5A V28M (a change of V to M at position 28) and NS5B A442V, compared with the baseline. Overall, this newly identified 6xj subtype further confirmed the high diversity of the HCV-6 genotype. The newly identified resistance-associated amino acid substitutions may help inform future clinical treatments. IMPORTANCE This study investigated the genetic diversity of hepatitis C virus (HCV), particularly in relation to genotype 6, which is prevalent in Yunnan, China, and is often difficult to treat successfully. We identified a new HCV-6 subtype, 6xj, which is an ancient strain. Moreover, all eight individuals with the novel subtype received follow-up assessments at 44 weeks from the beginning of their treatments. One case relapsed after 8 months of withdrawal. NGS was conducted and showed that the isolate from the treatment failure case had two suspected antiviral resistance mutations, NS5A V28M and NS5B A442V, compared with the baseline. Overall, this newly identified 6xj subtype further confirmed the high diversity of the HCV-6 genotype. The newly identified resistance-associated amino acid substitutions may help inform future clinical treatments. We believe that our study makes a significant contribution to the literature based on the results described above.

Inter-laboratory automation of the in vitro micronucleus assay using imaging flow cytometry and deep learning.

The in vitro micronucleus assay is a globally significant method for DNA damage quantification used for regulatory compound safety testing in addition to inter-individual monitoring of environmental, lifestyle and occupational factors. However, it relies on time-consuming and user-subjective manual scoring. Here we show that imaging flow cytometry and deep learning image classification represents a capable platform for automated, inter-laboratory operation. Images were captured for the cytokinesis-block micronucleus (CBMN) assay across three laboratories using methyl methanesulphonate (1.25-5.0 µg/mL) and/or carbendazim (0.8-1.6 µg/mL) exposures to TK6 cells. Human-scored image sets were assembled and used to train and test the classification abilities of the "DeepFlow" neural network in both intra- and inter-laboratory contexts. Harnessing image diversity across laboratories yielded a network able to score unseen data from an entirely new laboratory without any user configuration. Image classification accuracies of 98%, 95%, 82% and 85% were achieved for 'mononucleates', 'binucleates', 'mononucleates with MN' and 'binucleates with MN', respectively. Successful classifications of 'trinucleates' (90%) and 'tetranucleates' (88%) in addition to 'other or unscorable' phenotypes (96%) were also achieved. Attempts to classify extremely rare, tri- and tetranucleated cells with micronuclei into their own categories were less successful (≤ 57%). Benchmark dose analyses of human or automatically scored micronucleus frequency data yielded quantitation of the same equipotent concentration regardless of scoring method. We conclude that this automated approach offers significant potential to broaden the practical utility of the CBMN method across industry, research and clinical domains. We share our strategy using openly-accessible frameworks.

Effective and Safe Daclatasvir Drug Exposures Predicted in Children Using Adult Formulations.

BACKGROUND: Sofosbuvir (SOF)/daclatasvir (DCV) is the direct-acting antiviral regimen of choice in many low- and middle-income countries for curative treatment of chronic hepatitis C virus (HCV) infection in adults, but data on the use of DCV in children are lacking. We performed a population pharmacokinetic (PK) analysis to predict DCV exposure in children treated with available adult formulations. METHODS: DCV concentration data from HCV-infected adolescents receiving SOF/DCV [400/60 mg, once daily (OD)] who participated in a PK study in Egypt were used for model development. PK parameters were estimated using a population approach. Monte Carlo simulations were run for virtual children weighing 10 to <35 kg receiving 60 or 30 mg OD, and DCV exposures were compared with adults ranges. RESULTS: Seventeen HCV-infected adolescents (13 males) provided 151 DCV concentrations. Median (range) age was 14 (11-18) years and weight 50 (32-63) kg. In these adolescents receiving 60 mg DCV, median (interquartile range) DCV area under the concentration time curve 0 to 24 hours, maximum concentrations, and minimum concentrations were 11,130 (8140-14,690) ng·h/mL, 1030 (790-1220) ng/mL and 130 (110-220) ng/mL, respectively, compared with 10,343 (7661-14,095) ng·h/mL, 1132 (876-1518) ng/mL and 110 (55.7-192) ng/mL predicted in children 10 to <35 kg receiving 30 mg. The proportion of children with DCV exposures above the adult range rapidly increased for children <30 kg using 60 mg OD, similarly for children 10-14 kg using 30 mg. CONCLUSIONS: DCV 30 mg OD was predicted to achieve effective and safe exposures in children 14 to <35 kg, perhaps down to 10 kg. These results should be validated clinically. Low-cost available adult DCV formulations together with approved pediatric doses of SOF would expand global access to HCV treatment for children.

Sofosbuvir-based therapies in genotype 2 hepatitis C virus cirrhosis: A real-life experience with focus on ribavirin dose.

This study aimed to investigate the efficacy and safety of sofosbuvir-based therapies for the treatment of cirrhosis from hepatitis C virus (HCV) genotype 2 infection. Data of all consecutive HCV genotype 2 cirrhotic patients who started sofosbuvir-based treatments between January 2015 and March 2017 in eight Italian tertiary hospitals were collected retrospectively. Overall, 273 patients (Child A: 94.5%) were enrolled. In the 194 subjects treated with sofosbuvir/ribavirin, median initial ribavirin dosage was 13.9 mg/kg/day, and therapy duration was 16 weeks. Sustained virological response (SVR) rates were 93.8% in intention-to-treat (ITT) and 95.3% in per-protocol (PP) analyses for the 129 treatment-naïve patients, and 96.9% (ITT) and 98.4% (PP) for the 65 treatment-experienced subjects. Adverse events were reported in 142 patients (73.2%), but only 1.5% discontinued treatment. Eighty-eight subjects with treatment-induced anemia (mild: 34.5%, moderate: 7.7%, severe: 3.1%) had to reduce ribavirin dosage, but SVR rates were comparable to the weight-based dose group, both in ITT (95.4% and 94.3%) and PP (97.7% and 95.2%) analyses, respectively. Moreover, ITT and PP SVR rates were similar between shorter (<20 weeks) (94.1% and 96.0%, respectively) and prolonged (≥20 weeks) regimens (95.7% and 96.7%, respectively). SVR rates in the 79 subjects treated with sofosbuvir/daclatasvir (without ribavirin) were similar (ITT: 96.2%; PP: 97.4%, respectively), without de novo/worsening anemia. In conclusion, in a real-life study centered on genotype 2 patients with well-compensated cirrhosis, sofosbuvir-based regimens were associated with good SVR and tolerability rates, regardless of previous antiviral treatments, without a significant impact of on treatment ribavirin dose reductions.

Santacruzamate A Compositions, Analogs and Methods of Use: A Patent Evaluation of WO 2014/018913 (A2).

BACKGROUND: Santacruzamate A (SCA) is a natural product isolated from a marine cyanobacterium. Activity test results revealed that SCA is a highly potent HDAC2 inhibitor with an IC50 value of 0.112 nM. The IC50 of SCA in inhibiting cancer cell proliferation is 28.3 µM and 1.3µM on HCT116 and HuT-78 cells, respectively. OBJECTIVE: To develop HDAC inhibitors with improved activity, SCA analogs were synthesized for the Structure-Activity Relationship (SAR) studies. METHODS: Various substituted groups were introduced into the zinc binging group, linker, and cap regions of SCA by various chemical synthetic methods. RESULTS: Compared with SCA, the derivatives of SCA did not exhibit improved HDAC2 inhibitory activity. Nevertheless, several molecules such as III-32, III-33, IV-4b, and IV-11 showed improved activity in inhibiting cell proliferation on HCT116 and HuT-78 cells. CONCLUSION: Collectively, a potent HDAC2 inhibitor SCA was discovered as a lead compound for further development of selective HDAC inhibitors.

The Pharmacology and Clinical Efficacy of Antiseizure Medications: From Bromide Salts to Cenobamate and Beyond.

Epilepsy is one of the most common and disabling chronic neurological disorders. Antiseizure medications (ASMs), previously referred to as anticonvulsant or antiepileptic drugs, are the mainstay of symptomatic epilepsy treatment. Epilepsy is a multifaceted complex disease and so is its treatment. Currently, about 30 ASMs are available for epilepsy therapy. Furthermore, several ASMs are approved therapies in nonepileptic conditions, including neuropathic pain, migraine, bipolar disorder, and generalized anxiety disorder. Because of this wide spectrum of therapeutic activity, ASMs are among the most often prescribed centrally active agents. Most ASMs act by modulation of voltage-gated ion channels; by enhancement of gamma aminobutyric acid-mediated inhibition; through interactions with elements of the synaptic release machinery; by blockade of ionotropic glutamate receptors; or by combinations of these mechanisms. Because of differences in their mechanisms of action, most ASMs do not suppress all types of seizures, so appropriate treatment choices are important. The goal of epilepsy therapy is the complete elimination of seizures; however, this is not achievable in about one-third of patients. Both in vivo and in vitro models of seizures and epilepsy are used to discover ASMs that are more effective in patients with continued drug-resistant seizures. Furthermore, therapies that are specific to epilepsy etiology are being developed. Currently, ~ 30 new compounds with diverse antiseizure mechanisms are in the preclinical or clinical drug development pipeline. Moreover, therapies with potential antiepileptogenic or disease-modifying effects are in preclinical and clinical development. Overall, the world of epilepsy therapy development is changing and evolving in many exciting and important ways. However, while new epilepsy therapies are developed, knowledge of the pharmacokinetics, antiseizure efficacy and spectrum, and adverse effect profiles of currently used ASMs is an essential component of treating epilepsy successfully and maintaining a high quality of life for every patient, particularly those receiving polypharmacy for drug-resistant seizures.

Quality of life in patients with BRAF-mutant melanoma receiving the combination encorafenib plus binimetinib: Results from a multicentre, open-label, randomised, phase III study (COLUMBUS).

BACKGROUND: In COLUMBUS, treatment with encorafenib plus binimetinib in patients with advanced BRAF-mutant melanoma showed improved progression-free and overall survival with favourable tolerability compared to vemurafenib treatment. Here, results on health-related quality of life (HRQoL) are presented. METHODS: COLUMBUS was a two-part, open-label, randomised, phase III study in patients with BRAF-mutant melanoma. In PART-I, 577 patients were randomised (1:1:1) to encorafenib plus binimetinib, encorafenib or vemurafenib. The primary objective was to assess progression-free survival. As a secondary objective, HRQoL was assessed by the EQ-5D, the EORTC QLQ-C30 and the FACT-M questionnaires. Furthermore, time to definitive 10% deterioration was estimated with a Kaplan-Meier analysis and differences in mean scores between groups were calculated with a mixed-effect model for repeated measures. Hospitalisation rate and the impact of hospitalisation on HRQoL were also assessed. RESULTS: Patients receiving the combination treatment showed improvement of their FACT-M and EORTC QLQ-C30 global health status scores, compared to those receiving vemurafenib (post-baseline score differences: 3.03 [p < 0.0001] for FACT M and 5.28 [p = 0.0042] for EORTC QLQ-C30), indicative of a meaningful change in patient's status. Furthermore, a delay in the deterioration of QoL was observed in non-hospitalised patients compared to hospitalised patients (hazard ratio [95% CI]: 1.16 [0.80; 1.68] for EORTC QLQ-C30 and 1.27 [0.81; 1.99] for FACT-M) and a risk reduction of 10% deterioration, favoured the combination in both groups. CONCLUSION: The improved efficacy of encorafenib plus binimetinib compared to vemurafenib, translates into a positive impact on the perceived health status as assessed by the HRQoL questionnaires. The study is registered with ClinicalTrials.gov, number NCT01909453 and EudraCT number 2013-001176-38.

Elbasvir/grazoprevir administered for 12 weeks via percutaneous endoscopic gastrostomy tube achieves sustained virologic response: A case report and a review of the literature.

Enteral tubes are necessary for certain patients; however, medication absorption can be affected by this route of administration potentially resulting in decreased efficacy. All first-line treatments for Hepatitis C Virus (HCV) infection are only available as tablets and may have decreased absorption if administered via an enteral tube. This report describes the first case of a pegylated interferon and ribavirin treatment-experienced patient who successfully achieved HCV cure after 12 weeks of elbasvir/grazoprevir administered via percutaneous gastrostomy tube. We further review the available pharmacokinetic and clinical literature regarding administration via enteral feeding tubes for all first-line direct-acting antivirals (DAAs). The literature suggests that crushed administration can be considered for DAAs in patients with gastric access. However, caution should be exercised in patients with extragastric enteral tubes and in those with altered gastrointestinal tract anatomy.

Improving the Translation of Organic Anion Transporting Polypeptide Substrates using HEK293 Cell Data in the Presence and Absence of Human Plasma via Physiologically Based Pharmacokinetic Modeling.

Accurately predicting the pharmacokinetics of compounds that are transporter substrates has been notoriously challenging using traditional in vitro systems and physiologically based pharmacokinetic (PBPK) modeling. The objective of this study was to use PBPK modeling to understand the translational accuracy of data generated with human embryonic kidney 293 (HEK293) cells overexpressing the hepatic uptake transporters organic anion transporting polypeptide (OATP) 1B1/3 with and without plasma while accounting for transporter expression. Models of four OATP substrates, two with low protein binding (pravastatin and rosuvastatin) and two with high protein binding (repaglinide and pitavastatin) were explored, and the OATP in vitro data generated in plasma incubations were used for a plasma model, and in buffer incubations for a buffer model. The pharmacokinetic parameters and concentration-time profiles of pravastatin and rosuvastatin were similar and well predicted (within 2-fold of observed values) using the plasma and buffer models without needing an empirical scaling factor, whereas the dispositions of the highly protein bound repaglinide and pitavastatin were more accurately simulated with the plasma models than the buffer models. This work suggests that data from HEK293 overexpressing transporter cells corrected for transporter expression represent a valid approach to improve bottom-up PBPK modeling for highly protein bound OATP substrates with plasma incubations and low protein binding OATP substrates with or without plasma incubations. SIGNIFICANCE STATEMENT: This work demonstrates the bottom-up approach of using in vitro data directly without employing empirical scaling factors to predict the intravenous pharmacokinetic (PK) profiles reasonably well for four organic anion transporting polypeptide (OATP) substrates. Based on these results, using HEK293 overexpressing cells, examining the impact of plasma for highly bound compounds, and incorporating transporter quantitation for the lot in which the in vitro data were generated represents a valid approach to achieve more accurate prospective PK predictions for OATP substrates.

Pharmacology of Cenobamate: Mechanism of Action, Pharmacokinetics, Drug-Drug Interactions and Tolerability.

Cenobamate is one of the latest antiseizure medications (ASMs) developed for the treatment of focal onset seizures in adult patients. The recommended starting dose is 12.5 mg/day, titrated gradually to the target daily dose of 200 mg, which may be increased to a maximum of 400 mg/day based on clinical response. Although the high rate of seizure freedom observed in randomized, placebo-controlled clinical trials has resulted in exciting expectations, further clinical studies are needed to better define its clinical profile. Cenobamate is characterized by a peculiar pharmacology regarding both pharmacodynamics and pharmacokinetics. The mechanism of action has only partly been described, with the drug acting on voltage-gated sodium channels through a pronounced action on persistent rather than transient currents. Cenobamate also acts as a positive allosteric modulator of GABAA receptors independently from the benzodiazepine binding site. The bioavailability of cenobamate is not influenced by other drugs, except phenytoin; it can inhibit cytochrome P450 (CYP) 2C19 and induce CYP3A4 and 2B6, and hence can potentially interact with many drugs (e.g. dose adjustments may be required for lamotrigine, carbamazepine and clobazam). The pharmacokinetics of cenobamate are not linear and dosage increases imply a disproportional increase in plasma levels, particularly at doses higher than 300 mg. The most common and dose-related adverse effects associated with cenobamate include central nervous system-related symptoms, mainly somnolence, dizziness, diplopia, and disturbances in gait and coordination. A somewhat higher incidence of adverse events has been observed in patients concomitantly treated with sodium channel blockers. The most relevant safety issues are currently represented by the risk of severe skin reactions (apparently avoidable by a slow titration) and QT shortening (the drug is contraindicated in patients with familial short QT syndrome or taking QT-shortening drugs). Overall, cenobamate is a promising ASM with an intriguing and not fully understood mechanism of action; pharmacokinetic issues need to be considered in clinical practice.