Bidisomide (SC-40230), a new antiarrhythmic agent: initial study of tolerability and pharmacokinetics

Advanced Gene Therapy Strategies for the Repair of ACL Injuries

The anterior cruciate ligament (ACL), the principal ligament for stabilization of the knee, is highly predisposed to injury in the human population. As a result of its poor intrinsic healing capacities, surgical intervention is generally necessary to repair ACL lesions, yet the outcomes are never fully satisfactory in terms of long-lasting, complete, and safe repair. Gene therapy, based on the transfer of therapeutic genetic sequences via a gene vector, is a potent tool to durably and adeptly enhance the processes of ACL repair and has been reported for its workability in various experimental models relevant to ACL injuries in vitro, in situ, and in vivo. As critical hurdles to the effective and safe translation of gene therapy for clinical applications still remain, including physiological barriers and host immune responses, biomaterial-guided gene therapy inspired by drug delivery systems has been further developed to protect and improve the classical procedures of gene transfer in the future treatment of ACL injuries in patients, as critically presented here.

Treatment of atrial fibrillation and paroxysmal supraventricular tachycardia with bidisomide. The Atrial Fibrillation Investigation with Bidisomide (AFIB) Investigators

BACKGROUND

Atrial fibrillation and paroxysmal supraventricular tachycardia are common disorders of the heart rhythm for which antiarrhythmic drug therapy is commonly prescribed. The Atrial Fibrillation Investigation with Bidisomide (AFIB) study was a randomized, placebo-controlled clinical trial designed to accomplish three goals in a single protocol: (1) to determine the efficacy of the antiarrhythmic drug bidisomide in the treatment of these two arrhythmias; (2) to establish the appropriate dose range for bidisomide; and (3) to detect an adverse mortality effect of bidisomide if one were present in patients with atrial fibrillation.

METHODS AND RESULTS

In this clinical trial, 1227 patients with atrial fibrillation and 187 with paroxysmal supraventricular tachycardia were randomly assigned to bidisomide (200, 400, or 600 mg BID) or placebo; patient groups with each arrhythmia were analyzed separately. Symptomatic recurrences of atrial fibrillation and paroxysmal supraventricular tachycardia were documented with the use of transtelephonic ECG monitoring. The time to the first symptomatic arrhythmia recurrence was measured in each patient and compared among treatment groups. Among the atrial fibrillation patients, there was no significant difference in the time to first symptomatic recurrence between the placebo group and any of the three bidisomide treatment groups; the hazard ratios (placebo:treatment) were 1.19, 1.03, and 1.14 for bidisomide 200, 400, and 600 mg BID, respectively. Among paroxysmal supraventricular tachycardia patients, there was a similar lack of a significant treatment effect; the hazard ratios were 1.30, 1.93, and 1.59 for bidisomide 200, 400, and 600 mg BID, respectively. In the primary safety analysis of mortality, 3 of 493 patients taking placebo died, compared with 9 of 488 patients taking one of the two higher doses of bidisomide (P>.10).

CONCLUSIONS

Bidisomide in the doses tested did not have a clinically important antiarrhythmic effect. The AFIB study provided a novel clinical trial design to test antiarrhythmic drugs for both safety and efficacy.

A semicompartmental modeling approach for pharmacodynamic data assessment

A new method is proposed for modeling the temporal aspects of the pharmacodynamic-pharmacokinetic relationship of drugs. A semicompartmental solution to the effect-site link model of Sheiner et al. (1) formed the basis for this new approach. This semicompartmental solution does not require the specification of a compartmental model for the pharmacokinetic response and may offer an advantage when model misspecification is present in using standard compartmental models. A Monte Carlo simulation study was conducted to evaluate the performance of the semicompartmental modeling approach. This method is easily implemented in standard nonlinear regression packages.