Big pharma M&A may keep booming, CEOs say By: CNBC.com News April 16, 2015 at 15:44 PM EDT For Pfizer and Merck, two big names that have ridden the merger wave, buying up more business is a possibility, their CEOs said. Read More >> Related Stocks: Hospira Merck & Co Mylan Perrigo Pfizer Teva Pharmaceutical Industries ADR