Look out, J&J. Sun Pharma's Yonsa nod in prostate cancer puts Zytiga on notice

Early this year, Johnson & Johnson prostate cancer blockbuster Zytiga took an unexpected hit when a U.S. court stripped away a key patent, opening the prospect of generic launches later this year—a prospect J&J is working hard to avoid. But as of Wednesday, the $1.2 billion drug has copycat competition from another quarter.