Put another win in Merck's (NYSE: MRK) column. The column is labeled "What You Can Get From Buying a Company With a Well-Stocked Pipeline," of course.

Yesterday, Merck received Food and Drug Administration approval for Dulera, an asthma treatment developed by Schering-Plough, which it purchased last year.

Dulera is a combination of two drugs currently sold by Merck to treat asthma: Asmanex and Foradil, the latter of which is marketed outside the U.S. by Novartis (NYSE: NVS). Fordadil is a long-acting beta agonist (LABA), a class of drug that has come under FDA fire lately.

Combining a steroid with a LABA puts Dulera in line with AstraZeneca's (NYSE: AZN) Symbicort and GlaxoSmithKline's (NYSE: GSK) Advair, which are believed to be safer than LABAs alone. Dulera may siphon off some of the sales from its two individual components, but the increased safety profile could help bring in additional patients as well.

Dulera could also see a sales boost if it's approved as a treatment for chronic obstructive pulmonary disease (COPD). Foradil, one of the two components of Dulera, is already approved to treat COPD. Advair and Symbicort, which are both blockbusters, are also approved to treat the lung disease, as is Spiriva from Pfizer (NYSE: PFE) and Boehringer Ingelheim.

Dulera is a good start for Merck, but the biggest potential benefit from acquiring Schering-Plough's pipeline is yet to come. Phase 3 data from Schering's hepatitis C treatment, boceprevir, is set to read out later this year. Everyone expects boceprevir to work, but whether it'll top the bar set by Vertex Pharmaceuticals' (Nasdaq: VRTX) telaprevir remains to be seen. Blood-clot reducer vorapaxar, which Merck also got from Schering, is more of a long shot, but it would certainly be a blockbuster if it can prevent heart attacks.