In terms of Teva's timing, its patent is not scheduled to expire till May 2014; Mylan went public with its intention to sell generic Copaxone nearly a year and a half ago, in June 2008, when it announced a supply deal with India's Natco Pharma, but it's only a month ago that US regulators accepted Mylan's and Natco's application to challenge the Copaxone patents and make and sell their own version.
Teva's lawsuit would, according to the report, restrict approval of Mylan's generic version of the drug for up to 30 months - April 2012 - or until a court ruling in favour of Mylan, whichever comes first. Copaxone is worth fighting for, being reputedly responsible for roughly 20% to 25% of Teva's net profit. According to the article:
"Teva's position is that Copaxone is a highly complex drug. Because of the difficulty in characterizing its molecular structure, Teva says it doubts that any company could prove beyond doubt that its version is identical to the original Copaxone. The slightest error in characterizing the chemical structure of the drug could affect its activity, says Teva, and compromise the patient's safety".