Pharmacokinetic and pharmacodynamic profile of dronedarone , a new antiarrhythmic agent for the treatment of atrial fibrillation

Discovering Synergistic Compounds with BYL-719 in PI3K Overactivated Basal-like PDXs

Basal-like triple-negative breast cancer (TNBC) tumor cells are difficult to eliminate due to resistance mechanisms that promote survival. While this breast cancer subtype has low PIK3CA mutation rates when compared to estrogen receptor-positive (ER+) breast cancers, most basal-like TNBCs have an overactive PI3K pathway due to gene amplification or high gene expression. BYL-719 is a PIK3CA inhibitor that has been found to have low drug-drug interactions, which increases the likelihood that it could be useful for combinatorial therapy. Alpelisib (BYL-719) with fulvestrant was recently approved for treating ER+ breast cancer patients whose cancer had developed resistance to ER-targeting therapy. In these studies, a set of basal-like patient-derived xenograft (PDX) models was transcriptionally defined with bulk and single-cell RNA-sequencing and clinically actionable mutation profiles defined with Oncomine mutational profiling. This information was overlaid onto therapeutic drug screening results. BYL-719-based, synergistic two-drug combinations were identified with 20 different compounds, including everolimus, afatinib, and dronedarone, which were also found to be effective at minimizing tumor growth. These data support the use of these drug combinations towards cancers with activating PIK3CA mutations/gene amplifications or PTEN deficient/PI3K overactive pathways.

Predictors of dronedarone plasma drug concentrations and effect on atrial fibrillation/atrial flutter recurrence: Analyses from the EURIDIS and ADONIS studies

BACKGROUND

In this post hoc analysis, we assessed patient characteristics as predictors of dronedarone trough concentrations and characterized the relationship of trough concentrations of dronedarone with its efficacy and safety.

HYPOTHESIS

Dronedarone is recommended as a 400 mg twice daily dose taken orally with meals. We hypothesize that drug concentration/bioavailability of dronedarone, measured as above- and below-median trough concentrations, does not impact the efficacy outcomes.

METHODS

Average trough concentrations (Ctrough_avg ) across multiple timepoints were calculated for each patient, and patient Ctrough_avg values were categorized as below-median or above-median concentrations. The effect of patient baseline characteristics on dronedarone Ctrough_avg was assessed in the below-median versus above-median groups. The effect of dronedarone in each Ctrough_avg group versus placebo on risk of first atrial fibrillation/atrial flutter (AF/AFL) recurrence and safety was also evaluated.

RESULTS

Overall, 1795 plasma samples were available from 507 dronedarone-treated patients. An above-median Ctrough_avg was associated with age ≥75 years, female sex, lower weight, higher pacemaker use, and higher oral anticoagulant use. The risk of adjudicated first AF/AFL recurrence was significantly lower with dronedarone versus placebo in the below-median (hazard ratio [HR]: 0.71; 95% confidence interval [CI]: 0.56-0.91; p = .0054) and above-median groups (HR: 0.63; 95% CI: 0.50-0.81; p = .0002). No difference in risk of AF/AFL recurrence was observed between the above- and below-median groups. Safety and tolerability of dronedarone were similar between groups.

CONCLUSION

Significant reduction in AF/AFL recurrence was observed in patients treated with dronedarone versus placebo, regardless of dronedarone concentrations above or below the median value.

Comparison of dronedarone vs. flecainide in the maintenance of sinus rhythm, following electrocardioversion in adults with persistent atrial fibrillation: a systematic review and meta-analysis

AIMS

To compare flecainide and dronedarone for sinus rhythm (SR) maintenance following electrocardioversion of persistent atrial fibrillation (AF), in patients with minimal or no structural heart disease.

METHODS AND RESULTS

A systematic search of publications using EMBASE, CENTRAL, CINAHL, and MEDLINE (1989-2019), identified a total of 595 articles. No limitations were applied. Nine articles met the inclusion criteria [five randomized controlled trials (RCTs) and four cohort studies], encompassing 1349 persistent AF candidates. Two retrospective studies compared flecainide with dronedarone, indicating a 6% reduced risk of AF recurrence with flecainide; however, results were not statistically significant [risk ratio (RR) 0.94, 95% confidence interval (CI) 0.71-1.24; P = 0.66]. One RCT compared dronedarone to placebo, demonstrating a 28% reduced risk of AF recurrence at 6 months (RR 0.72, 95% CI 0.58-0.90; P = 0.004). Two RCTs compare flecainide to placebo, when a 16% decreased risk of AF recurrence at 6-12 months was indicated; however, these results were not statistically significant (RR 0.84, 95% CI 0.66-1.07; P = 0.16). Within a 6- to 12-month follow-up period, a combined recurrence rate of AF was examined, in which flecainide and dronedarone maintained SR in 50% and 42%, respectively. Four articles satisfied quality appraisal, one of which focused on flecainide data.

CONCLUSION

Dronedarone and flecainide displayed similar efficacy in maintaining SR in patients following electrocardioversion for persistent AF. The SR maintenance was numerically but not statistically significant in the flecainide group. Side effects uncovered similar pro-arrhythmic activity. However, in light of the deficiency of volume and quality of available evidence, the writer acknowledges the requirement for future research.

Impact of a Multichannel Blocker in Attenuating Intramyocardial Artery Remodeling in Hypertensive Rats through Increased Nitric Oxide Bioavailability

Dronedarone is recommended for the treatment of atrial fibrillation. However, we do not know its effect on vascular remodeling. This study was designed to assess whether dronedarone has the potential to improve the intramyocardial artery remodeling induced by chronic hypertension. Ten-month-old male spontaneously hypertensive rats (SHR) were randomly assigned to receive dronedarone (100 mg/kg) or vehicle. Age-matched male Wistar-Kyoto rats served as controls. After 14 days of treatment, we studied the structure (geometry and fibrosis) of the intramyocardial artery using histological analysis. Nitric oxide (NO) in plasma was analyzed. In the untreated SHR, we observed a significant increase in external diameter, lumen diameter, wall width, cross-sectional area, and collagen volume density, as was expected in the experimental model. Dronedarone induced a significant decrease in wall width, cross-sectional area, and collagen volume density in SHR-D in comparison with untreated SHR. The values obtained in SHR-D were similar in the WKY control group. We found significantly higher NO levels in plasma in SHR-D than in untreated SHR. Dronedarone improves the intramyocardial artery remodeling induced by chronic hypertension in SHR through increased nitric oxide bioavailability.

Computational Modeling of Electrophysiology and Pharmacotherapy of Atrial Fibrillation: Recent Advances and Future Challenges

The pathophysiology of atrial fibrillation (AF) is broad, with components related to the unique and diverse cellular electrophysiology of atrial myocytes, structural complexity, and heterogeneity of atrial tissue, and pronounced disease-associated remodeling of both cells and tissue. A major challenge for rational design of AF therapy, particularly pharmacotherapy, is integrating these multiscale characteristics to identify approaches that are both efficacious and independent of ventricular contraindications. Computational modeling has long been touted as a basis for achieving such integration in a rapid, economical, and scalable manner. However, computational pipelines for AF-specific drug screening are in their infancy, and while the field is progressing quite rapidly, major challenges remain before computational approaches can fill the role of workhorse in rational design of AF pharmacotherapies. In this review, we briefly detail the unique aspects of AF pathophysiology that determine requirements for compounds targeting AF rhythm control, with emphasis on delimiting mechanisms that promote AF triggers from those providing substrate or supporting reentry. We then describe modeling approaches that have been used to assess the outcomes of drugs acting on established AF targets, as well as on novel promising targets including the ultra-rapidly activating delayed rectifier potassium current, the acetylcholine-activated potassium current and the small conductance calcium-activated potassium channel. Finally, we describe how heterogeneity and variability are being incorporated into AF-specific models, and how these approaches are yielding novel insights into the basic physiology of disease, as well as aiding identification of the important molecular players in the complex AF etiology.

Dronedarone produces early regression of myocardial remodelling in structural heart disease

Background and aims

Left ventricular hypertrophy (LVH) in hypertension is associated with a greater risk of sustained supraventricular/atrial arrhythmias. Dronedarone is an antiarrhythmic agent that was recently approved for the treatment of atrial fibrillation. However, its effect on early regression of LVH has not been reported. We tested the hypothesis that short-term administration of dronedarone induces early regression of LVH in spontaneously hypertensive rats (SHR_s).

Methods

Ten-month-old male SHR_s were randomly assigned to an intervention group (SHR-D), where animals received dronedarone treatment (100 mg/kg) for a period of 14 days, or to a control group (SHR) where rats were given vehicle. A third group with normotensive control rats (WKY) was also added. At the end of the treatment with dronedarone we studied the cardiac anatomy and function in all the rats using transthoracic echocardiogram, cardiac metabolism using the PET/CT study (2-deoxy-2[18F]fluoro-D-glucose) and cardiac structure by histological analysis of myocyte size and collagen content.

Results

The hypertensive vehicle treated SHR rats developed the classic cardiac pattern of hypertensive cardiomyopathy as expected for the experimental model, with increases in left ventricular wall thickness, a metabolic shift towards an increase in glucose use and increases in myocyte and collagen content. However, the SHR-D rats showed statistically significant lower values in comparison to SHR group for septal wall thickness, posterior wall thickness, ventricular mass, glucose myocardial uptake, size of left ventricular cardiomyocytes and collagen content. All these values obtained in SHR-D rats were similar to the values measured in the normotensive WKY control group.

Conclusion

The results suggest by three alternative and complementary ways (analysis of anatomy and cardiac function, metabolism and histological structure) that dronedarone has the potential to reverse the LVH induced by arterial hypertension in the SHR model of compensated ventricular hypertrophy.

Inclusion of terpenes in cyclodextrins: Preparation, characterization and pharmacological approaches

Terpenes constitute the largest class of natural products and are important resources for the pharmaceutical, food and cosmetics industries. However, due to their low water solubility and poor bioavailability there has been a search for compounds that could improve their physicochemical properties. Cyclodextrins (natural and derived) have been proposed for this role and have been complexed with different types of terpenes. This complexation has been demonstrated by using analytical techniques for characterizing complexes such as DSC, NMR, XRD, FTIR, and TGA. The formation of inclusion complexes has been able to improve drug characteristics such as bioavailability, solubility and stability; and to enhance biological activity and efficacy. This review shows strong experimental evidence that cyclodextrins improve the pharmacological properties of terpenes, and therefore need to be recognized as being possible targets for clinical use.