 Cyclerion Therapeutics, Inc. CYCN, a clinical-stage biopharmaceutical company developing soluble guanylate cyclase sGC stimulators for the treatment of serious and orphan diseases, today announced topline results from its CAPACITY Phase 2 proof-of-concept study of praliciguat, a once-daily, orally available systemic sGC stimulator, in heart failure with preserved ejection fraction HFpEF. The study did not meet statistical significance on its primary endpoint of improved exercise capacity from baseline as compared to placebo, measured by cardiopulmonary exercise testing CPET. 