Merck's ($MRK) once-a-week omarigliptin proved itself equal to Januvia, stacking up to a daily treatment that brought in about $3.9 billion for the company last year. In a Phase III study on 642 adults with Type 2 diabetes, a weekly dose of Januvia charted a similar effect on average blood glucose as daily Januvia administration, Merck said. The two drugs, which work by blocking a protein called DPP-4, charted similar safety profiles in the study, according to the company, and both had similar rates of adverse events as the placebo arm. Merck is now on track to file omarigliptin for FDA approval by the end of 2015, the company said, and it has already submitted the new treatment in Japan. More