2015 looks like going down as a big year for first generic approval to some very big Brand products. In 2013 (the last year with data), the top two US brand products were Abilify (aripiprazole tablets, sales US$6.5 billion) and Nexium (esomeprazole capsules, sales US$6.2 billion). Combined almost $13 billion, a lot of money!
In January 2015, Teva got final approval of a generic equivalent to Nexium following a paragraph IV settlement with Astra Zeneca and began marketing its generic. Admittedly only one generic which will not bring much price relief but others are close behind.
On April 28, 2015 OGD approved 4 generic equivalents to Abilify Tablets, ANDAs from Teva, Torrent, Hetero, and Alembic. Abilify still has an orphan indication exclusivity in force but FDA decided to allow generics to carve this out of the labeling. The brand company Otsuka sued for an injunction and the outcome is still awaited, although it is unlikely the court will interfere in FDA's decision.
So 2 of the biggest selling brand products of all time have both run into generic competition, competition which will save patients most of that $13 billion a year in due course.