ARCA Biopharma announces screening of first patient in Phase 2B/3 trial ARCA biopharma announced that the first patient has been genetically screened in GENETIC-AF, its Phase 2B/3 adaptive design clinical trial. The GENETIC-AF trial will evaluate Gencaro as a potential treatment for the prevention of atrial fibrillation in patients with heart failure and/or left ventricular dysfunction who also have a specific genotype of the beta-1 adrenergic receptor, which is believed to be present in approximately 50% of the U.S. population. There are currently seven active clinical trial sites recruiting patients for GENETIC-AF. The company anticipates having approximately 50 clinical trial sites for the Phase 2B portion of the trial. Last week, ARCA hosted the initial GENETIC-AF Investigator Meeting which brought together the physicians and research coordinators participating in the trial for information sharing and study-specific training.