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As AMD Drug Nears End of Phase I, Sirna Inks Ocular Disease Alliance with Allergan


In line with its strategy to partner with bigger players on its drug-development programs, Sirna Therapeutics announced last week that it has out-licensed its phase I age-related macular degeneration drug Sirna-027 to Allergan as part of a multi-year partnership focused on developing new RNAi drugs for eye diseases.

"What Sirna will bring to this alliance is the expertise we have in RNA chemistry and biology," Howard Robin, president and CEO of Sirna, said during a presentation at last week's UBS Global Life Sciences conference in New York. "Allergan will bring to this alliance all of their expertise in ocular disease, as well as — and this is equally important to what we bring — all of the unique delivery technology they have available to them."

Under the terms of the deal, Allergan will assume all additional development and future commercialization responsibilities for Sirna-027. The arrangement also calls for the companies to collaborate on new RNA-based drugs for other ophthalmic diseases, with Sirna providing optimized siRNA compounds against Allergan targets. Allergan will be responsible for all preclinical, clinical, and commercialization activities associated with these compounds.

In exchange, Sirna will be paid $5 million upfront, and stands to receive as much as $245 million in clinical milestones. Sirna is also entitled to an undisclosed percentage of worldwide royalties on the sale of drugs resulting from the alliance, as well as research funding and contract manufacturing revenues.

"In Allergan, we've got a global leader in eye care, so it's not like the [AMD] program is going to be subsumed into some huge entity where ocular [indications] could or could not be a core focus."

Additional terms of the deal were not disclosed.

"We were very strategic in whom we decided to partner with, and we had a lot of options available," Rebecca Galler Robison, senior director of corporate strategy at Sirna, told RNAi News this week. "In Allergan, we've got a global leader in eye care, so it's not like the [AMD] program is going to be subsumed into some huge entity where ocular [indications] could or could not be a core focus."

By inking the deal for Sirna-027 with Allergan, Sirna indicated it can be sure the drug, as well as any future ocular disease drugs the company develops, "are going to get attention," she said.

According to Robin, Sirna was able to seal its deal with Allergan largely because of the strong phase I data on Sirna-027, as well as the drug's current dosing schedule of once every eight weeks.

In November 2004, Sirna-027 became the second RNAi-based drug to enter clinical trials, behind Acuity Pharmaceuticals' AMD therapy Cand5 (see RNAi News, 11/26/2004). Six months later, however, Sirna edged ahead of Acuity when it presented early phase I data indicating its drug was safe and effective at the Association for Research in Vision and Ophthalmology annual meeting in Florida (see RNAi News, 5/6/2005). Acuity has yet to provide any information on Cand5 beyond stating that the drug appears safe and that additional data would be available before year-end.

For RNAi companies, the AMD field is a crowded one — largely due to the relative ease with which a drug can be delivered to the eye. Aside from Acuity and Sirna, Quark Biotech is pursuing the disease. Alnylam Pharmaceuticals had been developing its own AMD treatment, but recently dropped it citing stiff competition, primarily from Genentech's and Novartis' AMD therapy Lucentis, which has performed well in phase III trials (see RNAi News, 9/23/2005).

At the UBS meeting, however, Robin downplayed the threat Lucentis posed to rival AMD drugs, stating that while it is a "great" drug that will "have a very important impact on the age-related macular degeneration market … don't think for a minute that the market is satisfied.

"Lucentis does not cure this disease," he noted, adding that "there's lots of room for improvement" on the once-a-month intravitreal injection Lucentis therapy requires. "If you look at the possibility of improved efficacy and the possibility for improved dosing, you could easily imagine there're a lot of other drug possibilities," Robin said.

Robin said that phase I data on Sirna-027 indicates that a single, intravitreal dose of the drug either stabilized or improved the disease in 100 percent of the patients in the phase I study at eight weeks. "Twenty-three percent of the patients had an improvement in three lines or greater on the eye chart" measuring visual acuity, he added. The drug is slated to enter phase II trials in the first half of next year after phase I testing wraps up this year

For comparison, Robin said that in phase I trials "Lucentis had about 89 percent of patients stable or improved [with] about 26 percent of the patients [having] three lines or greater" improvement in vision. He pointed out that there has been no formal head-to-head study comparing Lucentis to Sirna-027.

Robin also pointed out during his conference presentation the difference in Sirna-027's and Lucentis' dosing regimens, noting that while Lucentis is administered once a month, the phase I data on Sirna-027 reflects a once-every-two-months dosing schedule.

As far as side-effect profiles, Robin said that while in phase I trials 33 percent of patients receiving Lucentis experienced mild ocular inflammation and 11 percent experienced statistically significant inflammation in the eye, "there is no ocular inflammation at all with Sirna-027" in the phase I trial.

All this, Robin noted, "has lead to a collaboration … with Allergan."

With Sirna-027 having been partnered out, Sirna is now free to focus on its other core drug programs, including its viral hepatitis and permanent hair removal efforts.

"Our [hepatitis C] compounds are being investigated right now in primates, and we expect to enter … clinical trials with an HCV compound [in the second half of] next year," Robison said. For the dermatology program, the company expects to file an investigational new drug application by the end of 2006, she added.

— Doug Macron ([email protected])