81. An isolated double-stranded RNA molecule, comprising:
(i) a sense strand and an antisense strand that form a double-stranded region of up to 25
base pairs, said sense strand having an identity in the double-stranded region of at least 85
percent to a target RNA molecule; and
(ii) at least one strand having a single-stranded 3’-overhang, wherein said 3’-overhang
has been stabilized against degradation; and
(iii) at least one nucleotide analogue,
wherein said RNA molecule is capable of target-specific RNA interference.
Note that Dicerna's RNAi triggers make use of the 2'-O-methyl modification which sometimes is found in the 3' overhang and can also have stabilizing activity. Taken together, this claim indeed questions Dicerna's RNAi triggers, and although I would expect vigorous debate around whether 25 base-pairs are covered by the patent's description requirements should it come to a patent litigation, the assumption is that Alnylam's new patent rightfully questions many, if not most of the RNAi triggers used by Dicerna currently.
Since I'm at it, the new patent also comes awfully close to the asymmetric RNAi trigger designs by RXi Pharmaceuticals and others (asiRNAs). RXi e.g. uses dsRNA lengths of below 15bp with the guide strand having a long 3' overhang. I am a bit surprised that Alnylam got just enough extension both below and above their traditional 19-23bp stronghold to start overlapping with some asiRNA and Dicer-substrate designs.
Regardless, I stand by my point that Alnylam has re-invigorated their patent-related press releases in order to explain the valuation gap to its peers in the public markets. The original blog entry follows here:
This morning, Alnylam greeted the competition with another IP-related press release. It wrongly claims that a patent it just obtained covers competing technologies. This suggests that it either lacks an understanding of RNA technology basics or that it is afraid that the market will come to understand that the valuation difference to its peers has no basis in either a commercially more attractive clinical pipeline, a superior patent estate, or simply better technology.
[Note: in the original entry I mistakenly said Dicerna's triggers were 27 base-pairs; to be precise, they are 25/27 designs with 25 base-pairs and a 2 nucleotide 3' overhang on the guide.]