LEXINGTON, Mass.--(BUSINESS WIRE)--Cubist Pharmaceuticals, Inc. (NASDAQ: CBST) today announced the initiation of a pivotal Phase 3 trial of CXA-201 in patients with complicated urinary tract infections (cUTI). CXA-201 is being developed as a first-line intravenous therapy for the treatment of serious Gram-negative bacterial infections in the hospital, including those caused by multi-drug resistant Pseudomonas aeruginosa.