Shares of drugmaker Merck (MRK 0.35%) have climbed 18% since the start of 2013, but the company has faced a number of challenges this year: It decided to postpone its application for osteoporosis drug odanacatib and the FDA rejected both suvorexant and sugammadex. Merck has also been under pressure to reduce its R&D spending, and investors have long suggested that the company rethink its drug development process and cut costs. The company restructured its R&D operating division at the start of October, but it remains to be seen whether this new approach will increase the company's productivity. As investors wait to see whether Merck's R&D programs bear fruit in the years to come, what key topics should investors focus on right now? In the following video, analyst Max Macaluso discusses three key areas that Merck investors should watch and why they might impact this stock.