Big pharmaceutical companies are waging courtroom patent battles against each other over biosimilars, as the line blurs between companies known for their innovative medicines and those that produce cheaper biotech knock-offs.
Here are some of the high-profile cases:
* Sanofi sued Merck in U.S. federal court over its biosimilar version of Lantus insulin with around $7 billion in annual sales.
* Eli Lilly reached a royalties deal with Sanofi to end a similar Lantus-related lawsuit, but their pact means the biosimilar's launch was likely delayed.
* Amgen's aggressive legal strategy delayed Novartis's efforts to introduce the first U.S. biosimilar, Zarxio, before the copy of Amgen's $1 billion drug Neupogen finally went on sale last year.
* Pfizer and Korea's Celltrion in August beat back a court challenge from Johnson & Johnson over $10 billion autoimmune drug Remicade, though J&J's Janssen unit promised to appeal.
* In a closely watched case, Novartis wants the U.S. Supreme Court to dump a six-month marketing delay for biosimilars, in what would be the first time the high court took up a biosimilar case.
* Samsung Bioepis, along with partner and minority shareholder Biogen Inc, filed a lawsuit against AbbVie in Britain in March to stop the U.S. company from blocking the launch of yet another Humira biosimilar.
Reporting by John Miller; editing by Susan Thomas