Abo Abdullah, Humam

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease marked by cholestasis and progressive fibrosis. While ursodeoxycholic acid (UDCA) remains the first-line therapy, approximately 30–40% of patients have an inadequate biochemical response, increasing the risk of disease progression. Obeticholic acid (OCA), a potent farnesoid X receptor (FXR) agonist, was the first second-line agent approved by the only Food and Drug Administration (FDA) and has demonstrated moderate biochemical efficacy but limited tolerability due to dose-dependent pruritus and safety concerns in cirrhosis. Fenofibrate, a peroxisome proliferator-activated receptor alpha (PPAR-α) agonist, showed substantial alkaline phosphatase (ALP) reductions when added to UDCA, although its long-term benefit remains unconfirmed in large-scale trials and its use remains off-label in the United States, unlike FDA-approved agents. Seladelpar, a selective peroxisome proliferator-activated receptor delta (PPAR-δ) agonist, and elafibranor, a dual PPAR-α/δ agonist, have both recently received FDA accelerated approval after demonstrating significant improvements in ALP, biochemical response rates, and pruritus relief in phase 3 trials. This review summarizes these second-line therapies’ mechanisms, efficacy, safety, and limitations emphasizing the need for individualized treatment decisions and ongoing research into long-term clinical outcomes.

Background: Hypertrophic cardiomyopathy (HCM) is a genetic cardiomyopathy marked by increased left ventricular wall thickness, leading in some cases to left ventricular outflow tract (LVOT) obstruction, heart failure, and arrhythmias. Mavacamten, a selective allosteric inhibitor of cardiac myosin, has demonstrated benefits in improving hemodynamics and reducing LVOT obstruction. However, its impact on arrhythmic burden remains unclear, with reports of early atrial fibrillation (AF) risk contrasting with long-term reductions in arrhythmias. This study assesses the temporal patterns of Holter-detected arrhythmias in HCM patients treated with mavacamten. Methods: This retrospective study included HCM patients from three Mayo Clinic sites. Baseline demographic, clinical, and echocardiographic data were collected. Holter monitoring was performed at baseline, short-term (<6 months), and long-term (>6 months) follow-up. Arrhythmic events, including premature atrial contractions (PACs), premature ventricular contractions (PVCs), and supraventricular tachycardia (SVT), were analyzed using standardized rates per 24 h. Statistical comparisons utilized the Wilcoxon signed-rank test. Results: Twenty-seven patients (56% female, median age 66 years) were included. PACs, PVCs, and SVT duration transiently but not significantly increased at short-term follow-up but returned to baseline at long-term follow-up. No sustained or high-risk ventricular arrhythmias were observed. Conclusions: Mavacamten is associated with transient arrhythmic fluctuations early in treatment, followed by stabilization. These findings support its long-term electrophysiological safety and underscore the need for early rhythm monitoring. Further research should explore its role in arrhythmic risk stratification in HCM patients.