Wednesday, February 15, 2012

A Very Obvious Method of Generating Tuschl-type siRNAs

John Leavitt over at the RNAi Litigation blog just posted ‘Alnylam’s’ defense against the accusation of the University of Utah that Utah had been deprived of ownership over the 3’ overhang feature of the Tuschl-type siRNAs. Setting aside the underlying merits of the case, the Motion to Dismiss the Second Amended Complaint by the University of Utah highlights one thorny issue with the granted Tuschl II (T-II) patents in the US, namely that they, so far, do not claim the 3’ overhangs themselves, but a method of generating 3’ overhang siRNAs. This method stipulates, in a first step, the synthesis of the individual strands, and then, in a second step, hybridizing (‘combining’) them to form the 3’ overhung siRNAs. The motion by the Defense consequently argues that Utah is missing the point in its suit by alleging ownership over the 3’ overhang feature, but not the method of generating 3’ overhung siRNAs subject of the US patents.

This to me is a) misleading since the Tuschl II IP estate to which Utah lays claim includes the European T-II patent which expressly claims the overhangs and Alnylam/Max Planck are obviously hoping to get similar composition of matter claims issued in the US, and b) the issued US T-II could only be considered novel by the USPTO based on the novelty and utility of the composition of matter that results from this method, i.e. 3’ overhang siRNAs for inducing gene silencing.

That the USPTO issued these claims in the first place is quite puzzling. Synthesizing and combining small RNAs is the most obvious method of generating 3’ overhung siRNAs. I would argue that even the average highschool student can come up with this method after a basic lesson on nucleic acid structure, not to speak of the ‘person having ordinary skill in the art’ which is considered the standard for obviousness. Unless I have missed an important exception in US patent law, similar to the Swiss-style claim construction in Europe to which the US T-II claims are reminiscent of, the US T-II claims seem very tenuous to me and probably should not have been granted.

It is amazing that both Plaintiffs and Defense are spending all this energy (=time and legal fees) skirting around the main issues (namely that Tuschl was probably motivated to test the 3' overhang feature based on Bass' speculations, and that Bass cannot be named a (co-)inventor since there was not even a semi-formal collaboration between Bass and Tuschl and Utah never bothered to file a patent). The answer by Utah to this motion is predictable, and so it will go on and on...

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By Dirk Haussecker. All rights reserved.

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