 Shares of ARCA Biopharma Inc. gained 5.5 in trading on Monday after the company said it received a Fast-Track designation from the Food and Drug Administration for its mid-stage experimental COVID-19 treatment. ARCA plans to launch a Phase 2b clinical trial enrolling 100 hospitalized COVID-19 patients next month, and it anticipates that the first round of topline data from the study will be available in the second quarter of next year. 