Earnings season has been a mixed bag for big pharma so far this month, but the industry has a chance to score a big victory for investors when Merck (NYSE:MRK) reports its quarterly results next Wednesday. Merck has struggled with the patent cliff, like many of the top names in big pharma recently, and top drugs such as the diabetes-fighting duo Januvia and Janumet have struggled to gain significant sales growth.

Still, Merck has plenty going for its stock as one of the biggest names in health care. The firm's developmental cancer therapy, MK-3475, in particular has garnered high praise from analysts. Merck recently filed MK-3475 for regulatory approval in the U.S. as a melanoma treatment, and analysts project that the drug could one day garner up to $3 billion in annual sales if Merck can score approvals for more uses of the therapy.

MK-3475's development is one thing to watch in Merck's upcoming performance report, but what else do you need to keep an eye on? Find out what to watch from this top big pharma stock in the video below, as Motley Fool contributor Dan Carroll goes through the three most important things investors need to look out for in Merck's earnings -- and how they could make or break this stock heading into 2014.