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Silence Therapeutics CEO Dismisses Alnylam's Criticism of Zamore Patent Portfolio


By Doug Macron

Silence Therapeutics' CEO this week dismissed statements made by officials from rival Alnylam Pharmaceuticals that certain of its key US patents hold no value in the RNAi drugs space, saying that "we don't have the same assessment of this [intellectual property] as Alnylam apparently has."

"We do think it's important and we do think it's valuable, both to Silence and to other people in the industry," Philip Haworth told Gene Silencing News this week. "We believe there will be licensing activity in this area in the future."

The patents at issue are the so-called Zamore patents, the most recent of which — No. 7,772,203 — was granted by the US Patent and Trademark Office last week. They generally relate to siRNA design rules that are meant to improve RNAi-mediating agents.

Alnylam CEO John Maraganore made the remarks regarding the Silence IP during the company's second-quarter conference call last week. Noting that Phillip Zamore, the University of Massachusetts Medical School researcher who spearheaded the work from which the patents are derived, is an Alnylam co-founder, Maraganore said he was "aware of [the IP] years ago … [but] chose not to license it … because it wasn't worth anything from our perspective" (see related story, this issue).

Alnylam President and COO Barry Greene added that the patents have "zero" impact on how Alnylam designs its siRNA payloads.

While Maraganore's conclusion may be appropriate for Alnylam, "we don't agree that this IP is of zero importance," Haworth said. "We're using sequences that fall under the Zamore [design] criteria [and] we believe that there are real advantages to using those design rules to make sequences more potent and potentially safer."

At the same time, Silence believes that there are others developing siRNA-based drugs that are incorporating the Zamore rules into their sequences, although "perhaps they don't know they're using them." Meantime, others would like to incorporate the rules into their drug candidates, he added.

"There is the general belief that [some RNAi drug developers] have applied some of the [Zamore] characteristics" into their drug candidates, Haworth said. "If you look at some of the research houses, they will tell you on their websites that they use the Zamore design rules to make sequences.

"Do those research tools end up in products? I don't know," he continued. "But I wouldn't be at all surprised if some of them have been considered for those products."

Haworth noted that it is impossible for Silence to know which companies may be already using the design rules because the publication of such siRNA sequences is likely "years away." However, "presumably, nobody is going to launch a product if they believe it infringes," he said.

"Our goal is to have people come to us and ask about licensing the technology … and we will be happy to engage in those conversations," he added. "We've very optimistic that [the Zamore IP] is a valuable asset … and … we believe others will come to the same conclusion."

Haworth also suggested that Alnylam's contentious relationship with UMMS may have influenced the company's decision to pass on the chance to license the Zamore IP, if it even had the opportunity to do so.

"I think that the relationship between the University of Massachusetts Medical School and Alnylam is not the happiest or the most productive at this point in time," he said, citing an ongoing patent dispute between the company and the school (GSN 7/9/2009). "So I think it would have been difficult for [Alnylam] to get this technology, even if [it] had wanted it."

Haworth also took issue with Alnylam's publicly disclosed position that access to its own IP estate is mandatory for any other company looking to develop RNAi-based therapeutics.

On its website, Alnylam states that its estate comprises "fundamental RNAi patents and patent applications required for the development and commercialization of all RNAi therapeutics."

"We believe that we will not need a license from Alnylam to develop the products we have in our pipeline," Haworth said. "That's not to say they don't have IP that's useful, but we believe we've worked our way around the requirements to license that.

"We've never believed there will be a single party from whom all of these products flow," he concluded. "It's just not the way science works."