Assessment of drug interaction potential between the HCV direct-acting antiviral agents elbasvir/grazoprevir and the HIV integrase inhibitors raltegravir and dolutegravir.

BACKGROUND: Elbasvir/grazoprevir is a once-daily fixed-dose combination therapy for the treatment of chronic HCV infection, including HCV/HIV coinfection. OBJECTIVES: To evaluate the pharmacokinetic interaction of elbasvir and grazoprevir with raltegravir or dolutegravir. METHODS: Three open-label trials in healthy adult participants were conducted. In the raltegravir trials, participants received a single dose of raltegravir 400 mg, a single dose of elbasvir 50 mg or grazoprevir 200 mg, and raltegravir with either elbasvir or grazoprevir. In the dolutegravir trial, participants received a single dose of dolutegravir 50 mg alone or co-administered with once-daily elbasvir 50 mg and grazoprevir 200 mg. RESULTS: The raltegravir AUC0-∞ geometric mean ratio (GMR) (90% CI) was 1.02 (0.81-1.27) with elbasvir and 1.43 (0.89-2.30) with grazoprevir. Dolutegravir AUC0-∞ GMR (90% CI) was 1.16 (1.00-1.34) with elbasvir and grazoprevir. The elbasvir AUC0-∞ GMR (90% CI) was 0.81 (0.57-1.17) with raltegravir and 0.98 (0.93-1.04) with dolutegravir. The grazoprevir AUC0-24 GMR (90% CI) was 0.89 (0.72-1.09) with raltegravir and 0.81 (0.67-0.97) with dolutegravir. CONCLUSIONS: Elbasvir or grazoprevir co-administered with raltegravir or dolutegravir resulted in no clinically meaningful drug-drug interactions and was generally well tolerated. These results support the assertion that no dose adjustments for elbasvir, grazoprevir, raltegravir or dolutegravir are needed for co-administration in HCV/HIV-coinfected people.

No clinically meaningful pharmacokinetic interaction between the hepatitis C virus inhibitors elbasvir and grazoprevir and the oral contraceptives ethinyl estradiol and levonorgestrel.

PURPOSE: Oral contraceptive pills (OCPs) are an important element of hepatitis C virus (HCV) treatment in women of childbearing potential. These studies evaluated the safety and pharmacokinetic interactions between elbasvir (EBR) and grazoprevir (GZR) and ethinyl estradiol/levonorgestrel (EE/LNG). METHODS: Both studies were open-label, single-site, two-period, fixed-sequence, one-way interaction studies. In period 1, subjects received one tablet of EE/LNG (0.03 mg/0.15 mg). In period 2, subjects received EBR (50 mg once daily) for 13 days or GZR (200 mg once daily) for 10 days, with one tablet of EE/LNG on day 7 (GZR group) or 10 (EBR group). Each study enrolled 20 healthy, nonsmoking adult females. RESULTS: There was no clinically meaningful effect of multiple doses of EBR or GZR on the pharmacokinetics of EE or LNG. Geometric mean ratios (GMRs) for AUC0-∞ and Cmax in the presence and absence of EBR were 1.01 and 1.10 for EE and 1.14 and 1.02 for LNG, with 90% confidence intervals (CIs) that were contained in the interval [0.80, 1.25]. Similarly, the AUC0-∞ and Cmax GMRs in the presence and absence of GZR were 1.10 and 1.05 for EE and 1.23 and 0.93 for LNG, respectively. The 90% CIs for EE AUC0-∞ and for EE and LNG Cmax were contained in the interval [0.80, 1.25]; however, the 90% CI for the LNG AUC0-∞ [1.15, 1.32] slightly exceeded the upper bound. CONCLUSIONS: These results suggest that EBR/GZR can be co-administered to female patients with HCV of childbearing potential who are on OCPs to prevent pregnancy.

Multisite Validation of a Functional Assay to Adjudicate SCN5A Brugada Syndrome-Associated Variants.

BACKGROUND: Brugada syndrome is an inheritable arrhythmia condition that is associated with rare, loss-of-function variants in SCN5A. Interpreting the pathogenicity of SCN5A missense variants is challenging, and ≈79% of SCN5A missense variants in ClinVar are currently classified as variants of uncertain significance. Automated patch clamp technology enables high-throughput functional studies of ion channel variants and can provide evidence for variant reclassification. METHODS: An in vitro SCN5A-Brugada syndrome automated patch clamp assay was generated and independently studied at Vanderbilt University Medical Center and Victor Chang Cardiac Research Institute. The assay was calibrated according to ClinGen Sequence Variant Interpretation recommendations using high-confidence variant controls (n=49). Normal and abnormal ranges of function were established based on the distribution of benign variant assay results. Odds of pathogenicity values were derived from the experimental results according to ClinGen Sequence Variant Interpretation recommendations. The calibrated assay was then used to study SCN5A variants of uncertain significance observed in 4 families with Brugada syndrome and other arrhythmia phenotypes associated with SCN5A loss-of-function. RESULTS: Variant channel parameters generated independently at the 2 research sites showed strong correlations, including peak INa density (R2=0.86). The assay accurately distinguished benign controls (24/25 concordant variants) from pathogenic controls (23/24 concordant variants). Odds of pathogenicity values yielded 0.042 for normal function and 24.0 for abnormal function, corresponding to strong evidence for both American College of Medical Genetics and Genomics/Association for Molecular Pathology benign and pathogenic functional criteria (BS3 and PS3, respectively). Application of the assay to 4 clinical SCN5A variants of uncertain significance revealed loss-of-function for 3/4 variants, enabling reclassification to likely pathogenic. CONCLUSIONS: This validated high-throughput assay provides clinical-grade functional evidence to aid the classification of current and future SCN5A-Brugada syndrome variants of uncertain significance.

Development of automated patch clamp assays to overcome the burden of variants of uncertain significance in inheritable arrhythmia syndromes.

Advances in next-generation sequencing have been exceptionally valuable for identifying variants in medically actionable genes. However, for most missense variants there is insufficient evidence to permit definitive classification of variants as benign or pathogenic. To overcome the deluge of Variants of Uncertain Significance, there is an urgent need for high throughput functional assays to assist with the classification of variants. Advances in parallel planar patch clamp technologies has enabled the development of automated high throughput platforms capable of increasing throughput 10- to 100-fold compared to manual patch clamp methods. Automated patch clamp electrophysiology is poised to revolutionize the field of functional genomics for inheritable cardiac ion channelopathies. In this review, we outline i) the evolution of patch clamping, ii) the development of high-throughput automated patch clamp assays to assess cardiac ion channel variants, iii) clinical application of these assays and iv) where the field is heading.

Multi-site validation of a functional assay to adjudicate SCN5A Brugada Syndrome-associated variants.

Brugada Syndrome (BrS) is an inheritable arrhythmia condition that is associated with rare, loss-of-function variants in the cardiac sodium channel gene, SCN5A. Interpreting the pathogenicity of SCN5A missense variants is challenging and ~79% of SCN5A missense variants in ClinVar are currently classified as Variants of Uncertain Significance (VUS). An in vitro SCN5A-BrS automated patch clamp assay was generated for high-throughput functional studies of NaV1.5. The assay was independently studied at two separate research sites - Vanderbilt University Medical Center and Victor Chang Cardiac Research Institute - revealing strong correlations, including peak INa density (R2=0.86). The assay was calibrated according to ClinGen Sequence Variant Interpretation recommendations using high-confidence variant controls (n=49). Normal and abnormal ranges of function were established based on the distribution of benign variant assay results. The assay accurately distinguished benign controls (24/25) from pathogenic controls (23/24). Odds of Pathogenicity values derived from the experimental results yielded 0.042 for normal function (BS3 criterion) and 24.0 for abnormal function (PS3 criterion), resulting in up to strong evidence for both ACMG criteria. The calibrated assay was then used to study SCN5A VUS observed in four families with BrS and other arrhythmia phenotypes associated with SCN5A loss-of-function. The assay revealed loss-of-function for three of four variants, enabling reclassification to likely pathogenic. This validated APC assay provides clinical-grade functional evidence for the reclassification of current VUS and will aid future SCN5A-BrS variant classification.

A descriptive analysis of calls to the NSW Teratogen Information Service regarding use of anti-infectives during pregnancy.

BACKGROUND: MotherSafe is a free telephone-based counseling service for Australian consumers and health-care providers concerned about drug exposures during pregnancy and breastfeeding. Anti-infectives are the most commonly prescribed drugs for pregnant women. This study aims to provide a descriptive analysis of prospectively collected calls received by MotherSafe regarding anti-infective exposures during pregnancy between 2000 and 2020. Aggregate data were examined by type of caller, reason for call, pregnancy category and exposure type. Inductive thematic analysis of the comments recorded by MotherSafe counsellors at the time of call was undertaken. RESULTS: Over the study period, 25,890 calls related to exposure to anti-infectives during pregnancy (antibiotic, antiviral, and antifungal medications). Calls from patients were dominated by low-risk exposures (pregnancy category A) to drugs while calls from health care professionals related to drugs with limited human information (pregnancy category B3). Analysis of MotherSafe counsellor comments revealed over 200 instances of concerns relating to health care professional advice to the patient. Three themes emerged: incorrect or conflicting advice, poor counselling, and refusal to treat, prescribe or dispense. It is likely that these comments are biased to the negative as patients would not call MotherSafe if they were happy with HCP advice. However, the findings are concerning as they reveal an underlying lack of knowledge in some health care professionals which may have led to undertreatment of patients. This study reinforced the importance of Teratogen Information Services such as MotherSafe in providing counselling and clear communication of evidence-based information to guide decision-making, reducing potential emotional distress in pregnant women, and optimizing maternal, pregnancy and infant outcomes.

Design, synthesis, and evaluation of a novel dual FMS-like tyrosine kinase 3/stem cell factor receptor (FLT3/c-KIT) inhibitor for the treatment of acute myelogenous leukemia.

A high-throughput screen of our compound archive revealed a novel class of dual FMS-like tyrosine kinase 3 (FLT3)/c-KIT inhibitors. With the help of molecular modeling, this class was rapidly optimized for both potency against FLT3 and FLT3/c-KIT and excellent potency in cell-based assays, leading to dose-dependent cell death in acute myelogenous leukemia (AML) patient blast samples. Ultimately, the AML patient blast data defined the preferred target profile as we designed and evaluated a set of FLT3 selective and FLT3/c-KIT dual molecules. Further optimization for pharmacokinetic properties resulted in the selection of the dual FLT3/c-KIT inhibitor, N(3)-(4-(trans-4-morpholinocyclohexyl)phenyl)-1-(pyridin-2-yl)-1H-1,2,4-triazole-3,5-diamine, VX-322 (compound 37), to move forward to preclinical evaluation.