High Court refuses special leave concerning enantiomer patents

The High Court has refused to grant special leave from a decision of the Full Federal Court (H Lundbeck A/S v Alphapharm Pty Ltd [2009] FCAFC 70) concerning a patent for the (+)-enantiomer of citalopram, known as escitalopram.

Lundbeck sought special leave to appeal the Full Court’s decision that it was not entitled to an extension of term for its patent.  The Full Court had previously held that, for the purposes of Part 3 of the Patents Act 1990, the racemate citalopram consisted of or contained the (+)-enantiomer and ordered that the extension of the term of the escitalopram patent be removed (that order was stayed pending the special leave application).  Lundbeck argued that the correct question was whether the ‘isolated or separated’ enantiomer was found in a product on the Register of Therapeutic Goods.  Chief Justice French and Justice Gummow said that the Full Court’s construction of the statute was not attended by sufficient doubt to warrant the grant of leave and leave was refused.  Following this outcome Lundbeck’s extension of term will be removed.

In a separate application, Alphapharm sought leave to argue that the (+)-enantiomer of citalopram was not new in light of the existence of the racemate and that the proper construction of the claims was not to the pure or isolated or separated (+)-enantiomer of citalopram.  On this point, Chief Justice French and Justice Gummow concluded that “without endorsing in its entirety the approach to construction taken by the majority in the Full Court” the construction of the relevant claims was “on the face of it, correct”.  Accordingly, the prospects of success on an appeal were insufficient to warrant the grant of special leave.

Click here to view the full transcript.

More information on the Full Federal Court decision can be found here.

Mallesons acted for Alphapharm in these proceedings.

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