In the recent Federal Court decision of Sigma Pharmaceuticals (Australia) Pty Ltd (ACN 004 118 594) v Wyeth [2009] FCA 595 the patentee, Wyeth, successfully applied for interlocutory injunctive relief restraining Sigma from supplying a generic drug used to treat patients suffering from central nervous system disorders including depression.

Sigma conceded that there was a serious question to be tried as to infringement. Although there was conflicting evidence led by the parties in relation to invalidity, the Court found that Sigma had established a prima facie case for lack of inventive step and no new manner of manufacture.

Wyeth successfully argued:

  • it would suffer irreparable harm (for which damages would not be an adequate remedy) if the injunction were not granted. This was because if the generic product became available, Wyeth would lose market share and would be forced to reduce the product's price to remain competitive. Further, other generic companies would likely also enter the market.
  • the balance of convenience lay in favour of granting the injunction. This was because Wyeth's product had been on the market for some time whereas Sigma had only just launched its product; Sigma proceeded with its launch after it became aware of Wyeth's patent; and a change in the appearance of the medication (that is, if the interlocutory injunction was granted and then Wyeth succeeded at trial) could cause patients to become confused and not take their medication regularly.