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Sirna Announces Respiratory Deal with GSK, Wins First US Target-Specific Patent in RNAi

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Sirna Therapeutics announced this week that it has formed a multi-year alliance with GlaxoSmithKline for the discovery, development, and commercialization of RNAi-based treatments for respiratory diseases.

While the companies did not disclose specific indications they plan to investigate through the partnership, comments Sirna President and CEO Howard Robin made during a conference call this week strongly indicate that asthma will be an initial focus. He said there is "a high level of interest in asthma," and added that Sirna has "already presented some work we've done in the area of asthma [and] I'm pretty sure we'll continue that work with GSK."

Asked to comment on Robin's remarks, Gwenan Evans, director of science communications for GlaxoSmithKline, told RNAi News this week that the partnership would be investigating "a broad range" of respiratory conditions, but said that asthma and chronic obstructive pulmonary disease, as the two biggest respiratory indications, "would be a key focus for the research."

Separately this week, Sirna reported that the US Patent and Trademark Office has granted it the first RNAi target-specific patent in the US, increasing the likelihood the USPTO will award more of roughly 250 other target-specific patent applications the company has filed.


The deal with GlaxoSmithKline represents "a reproducible transaction model" of "therapeutic-focused and target-focused partnerships" that the company plans to incorporate into future collaborations.

"The issuance of this patent changes the IP landscape in the field of RNAi," Howard Robin, president and CEO of Sirna, said in a statement. "We believe that the combination of our target patents with our patents in siRNA design, chemistry, synthesis, and manufacturing gives Sirna Therapeutics a dominant intellectual property estate in the field of RNAi-based therapeutics."

The GSK Deal

Through the deal with Sirna, GlaxoSmithKline is betting RNAi will help build on its pulmonary drug-delivery expertise, which has yielded such products as the blockbuster Advair inhaler for asthma.

The British drugs giant has been aware of the therapeutic potential of RNAi for some time, and has conducted early-stage exploratory research in the area. But the partnership with Sirna is the company's most advanced effort with the gene-silencing technology to date, Evans noted.

Under the terms of the alliance, Sirna will provide GlaxoSmithKline with optimized and formulated siRNAs against targets specified by the drugmaker. GlaxoSmithKline will assume all preclinical and clinical development responsibilities for the compounds, as well any commercialization activities.

In exchange, Sirna will receive an upfront payment of $12 million, half in cash and half in the purchase of about 717,703 shares of Sirna common stock at $8.36 per share. The transaction will give GlaxoSmithKline an approximately 1.15-percent stake in Sirna.

Sirna also stands to receive as much as $700 million in milestone payments and royalties on the sale of products resulting from the alliance, and the company may receive contract manufacturing revenues on the production of clinical and commercial materials for GlaxoSmithKline.

Robin noted during the conference call that since "most of the work, even the preclinical testing of siRNAs in animal models, will be done by GSK they are absorbing most of the preclinical and clinical development work," which minimizes the costs Sirna will bear under the deal. He declined, however, to update Sirna's financial guidance for the year in light of the collaboration.

Additional terms were not disclosed.

According to Robin, the deal with GlaxoSmithKline represents "a reproducible transaction model" of "therapeutic-focused and target-focused partnerships" that the company plans to incorporate into future collaborations.


"The claims of the patent are not limited to any specific siRNA sequence, but cover any siRNA sequence used against the gene. In addition, the claims of this patent are not limited to a specific type of chemical modification or structure, but cover any chemical modification that can be made to the siRNA."

Michael French, Sirna's senior vice president of corporate development, added during the conference call that although the alliance is "focused in the area of respiratory diseases and conditions, [it] does not restrict Sirna's ability to create additional partnerships around other therapeutic areas; Sirna is not obligated to reserve targets or programs for GSK."

Robin said that the companies are "now starting to work on selected targets that GSK and Sirna have defined," and that announcements about the status of the collaboration will "probably [come] later this year."

Later in the call, while comparing the GlaxoSmithKline deal with the one Sirna signed with Allergan late last year for its experimental age-related macular degeneration drug (see RNAi News, 10/7/2005), Robin stated that the "asthma market is one of the largest drug markets in the United States," making this week's partnership "substantially larger than the Allergan deal."

He also noted in response to an analyst's question that the GlaxoSmithKline collaboration "will probably extend beyond asthma into other respiratory disorders as well."

Patent Poker

Also this week, the USPTO awarded Sirna patent No. 7,022,828, entitled "siRNA Treatment of Diseases or Conditions Related to Levels of IKK-Gamma. The company said that the patent is the first of its more than 250 target-specific RNAi patent applications to be granted by the patent office.

The patent claims "nucleic acid molecules, including antisense and enzymatic nucleic acid molecules, such as hammerhead ribozymes, DNAzymes, allozymes, aptamers, decoys, and siRNA, which modulate the expression or function of IKK genes, such as IKK-gamma, IKK-alpha, or IKK-beta, and PKR genes." It was filed in May 2002.

Bharat Chowrira, vice president of legal affairs and chief patent counsel at Sirna, noted during this week's conference call that "the claims of the patent are not limited to any specific siRNA sequence, but cover any siRNA sequence used against the gene. In addition, the claims of this patent are not limited to a specific type of chemical modification or structure, but cover any chemical modification that can be made to the siRNA," he said.

Robin added that the issuance of the patent "demonstrates that our other patents covering over 250 targets will issue in a similar fashion, thus potentially locking up some of the most important mammalian targets for siRNA drug discovery and development." He said that the company expects "additional patent allowances in the US this year."

Richard Warburg, an intellectual property attorney with Foley & Lardner who also represents Sirna, told RNAi News this week that the issuance of the '828 patent "is a positive sign from the patent office indicating that target patents are available in this field."

He said that he expects target-specific patents to be as important to establishing a strong IP position in the RNAi as the broader patents that cover the RNAi process in general.

"The broader ones give you a broader type of protection, but potentially open you up to more challenges "that's the quid pro quo," he said. Additionally, while patents with a narrow scope offer less protection individually, a combination of them can add up to a formidable patent estate.

Comparing the IP landscape to a card game, Warburg likened broad patents to aces and narrower ones to the lower cards in the deck. "You can [usually] win with the aces," he said, "but if you have lots of 2s, 3s, and 4s, all of a sudden you can get a full house. So the narrow ones and the broader ones all fit together, and ideally you want a bit of everything."

- Doug Macron ([email protected])

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