Patent Law

Australian Patent Office Clarifies Novelty Test For Enantiomers

By Stephen Albainy-Jenei

A recent decision of an Australian appeal court concerning a patent for an enantiomer pharmaceutical dealt with matters of patent claim validity and patent term extension. The decision, H Lundbeck A/S v Alphapharm Pty Ltd [2009] FCAFC 70, involves a decision of the Full Federal Court on rehearing an appeal by Alphapharm over an earlier decision regarding Lundbeck?s Australian Patent No. 623144 for the antidepressant drug escitalopram.

The Full Court upheld the earlier judge?s holding that the patent is valid and infringed but also upheld the finding that the term of Lundbeck?s patent was not properly extended.  As this decision may affect your Australian patents/patent applications we now summarise several key aspects of the decision.

Infringement

The initial judge had found non-literal infringement (effectively substitution of one halogen for another). This was overturned on appeal. This confirms that non-literal infringement is very rare in Australia, and therefore literal claim scope should be broader to achieve the same effective scope for infringement.

Novelty

The appeal court reviewed Australian authorities on anticipation. The issue was whether a racemate anticipated a claim that just named one enantiomer. By 2-1 majority, the court held the claim novel. There are two interesting aspects to this.

1. There was much argument around the claim because the claim just stated the name of the enantiomer, just as some claims merely state the name of the virus or gene or protein. Where the invention is in isolation of a natural material, the judgement confirms that the claims should be drafted more specifically (e.g., “A composition comprising ?”) or they risk anticipation by the substance in its native form. The dissenting judge may well have held that a composition of the substantially pure enantiomer was novel.
2. Where a patentee argues that a prior disclosure is not enabling, the court must determine whether the prior disclosure is sufficient to enable the skilled addressee to perceive, understand and, where appropriate, apply the prior disclosure ?necessarily? to obtain the invention. This leaves little room for integers to be added to a prior publication for novelty purposes, even if relatively minor.

Utility

The appeal court concluded a claim to a dosage form where the compound was present in an amount from 0.1 to 100mg per unit dose lacked utility and was therefore invalid for including quantities outside of the range of 5mg?40mg shown by the evidence to be the minimum to maximum clinical dosage range. This aspect of the decision could be particularly problematic for patentees and suggests that every value in a claimed range must be useful. This ground was not however extensively discussed and may be confined to the facts of this particular case. If there is uncertainty that a range encompasses only useful values, then dependent claims with progressively narrow ranges should be included into the patent/patent application.

Patent term extension

The appeal court confirmed the original judge?s decision that an extension of the term is not available for a patent which relates to a ?purified? version (such as an isolated enantiomer) of an earlier ?mixed? or ?impure? pharmaceutical product (such as a racemate), where the original was also registered as a pharmaceutical.

The above is a very general summary of the most pertinent aspects of the decision. If you would like any further information relating the aspects of the decision outlined above please do not hesitate to contact us.  A more detailed analysis can be found here.

Note: The order removing the extension of term for escitalopram (Lexapro) has been delayed pending any appeal by Lundbeck to the High Court.

Today’s post is by Guest Barista James Cherry, a Partner with Freehills Patent & Trade Mark Attorneys in Australia.

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Full post as published by Patent Baristas on June 24, 2009 (boomark / email).