BRISTOL, Pa.--(BUSINESS WIRE)--Nitric BioTherapeutics (Nitric Bio) today announced the beginning of a Phase II clinical trial for the treatment of chronic wounds using nitric oxide. Affecting between 4.5 and 5 million Americans in the form of diabetic, venous stasis and decubitus ulcers, chronic wounds cost the U.S. healthcare system in excess of $2.5 billion per year and results in significant burden to patients.