FDA approval for Merck’s Januvia today sets the stage for a major marketing battle in a new class of Type 2 diabetes drugs.Januvia is part of the emerging drug class of DPP-4 inhibitors, which enhance the body’s ability to lower elevated blood sugar. Novartis expects to see FDA approval for its DPP-4 drug Galvus by next month. Analysts have predicted sales of over $1 billion for both drugs. Physicians are ready to start prescribing the products right away, according to a survey conducted by Reuters Primary Research, which researches industry issues and trends for institutional investors. In a survey of about 60 endocrinologists, general practitioners and internists — who already had at least some awareness of the drugs — virtually all said they would use either Januvia or Galvus alone or in combination with other treatments. Of those physicians, about 90% of primary care practitioners said they intend to use Januvia and Galvus, while 95% of endocrinologists said they intended to use them.