Intellectual property laws today allow a company 20 years of patent protection from the date of filing. That's a bit different from the former laws that granted 17 years of protection from the date of issuance from the U.S. Patent and Trademark Office. Depending on how quickly an application moves through the office, a company today could enjoy an extra year or two of protection compared to the previous precedent. Unless, of course, you are Amgen (NASDAQ:AMGN).

By the time the last patent for TNF-alpha inhibitor Enbrel expires, it will have been on the market for 30 years! How is that possible? The patent was filed in 1995, reworked, rejected, appealed, reworked again, and finally accepted in late 2011. But because it was originally filed under the old laws, it was granted 17 years of protection from the date of issuance: 2011. So, although Enbrel first hit the market in 1998, it won't face total generic competition until 2028. Not even that has stopped a flurry of generic competition from arising, which Fool contributor Maxx Chatsko explains in the following video. 

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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