While cancer therapy regimens can successfully destroy malignant tumors, they can also have unintended consequences -- such as weakening the immune system. Luckily, Amgen (NASDAQ:AMGN) has pioneered several drugs that solve this problem in patients undergoing chemotherapy. And it has been very successful doing so. Aranesp and Epogen stimulate bone marrow to boost red blood cell count to combat anemia, while Neulasta and Neupogen boost white blood cell count to bolster the immune system and combat infections.

Neulasta is a longer-lasting version of Neupogen, which means that fewer injections are needed. That convenience allowed the drug to capture $4.1 billion in 2012 sales compared to $1.26 billion for its predecessor. However, Neulasta loses patent protection in the United States and Europe in 2015. In the following video, Fool contributor Maxx Chatsko breaks down the generic competition and what it means for investors.

Fool contributor Maxx Chatsko has no position in any stocks mentioned. Check out his personal portfolio, his CAPS page, or follow him on Twitter @BlacknGoldFool to keep up with his writing on energy, bioprocessing, and biotechnology.

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