This story has been updated to include additional comment from Roche.
NEW YORK (GenomeWeb) – Roche announced this week that it has signed a deal to acquire Santaris Pharma and its locked nucleic acid-based antisense technology for $250 million, plus up to $200 million more upon the achievement of certain milestones.
Notably, the deal comes roughly four years after Roche ended its in-house RNAi drug development efforts. A Roche spokesperson noted in an email this week that the company had found siRNAs too difficult to deliver to targets outside of the liver, constraining their therapeutic potential.
LNAs, in contrast, however, do not have this issue. Rather, they "potently and specifically bind and inhibit RNA targets in many different tissues without the need for complex delivery vehicles," the spokesperson wrote.
Following the acquisition, which is expected to close this month and comes just months after the companies inked a drug-discovery alliance, Santaris' Denmark facilities will be renamed Roche Innovation Center Copenhagen. Additional terms of the arrangement were not disclosed.
"Today, there are many disease targets that are very challenging or even impossible to reach with small molecules or antibodies," John Reed, head of Roche Pharma research and early development, said in a statement. "We believe the LNA platform provides the means to efficiently discover and develop an important new class of medicines that may address the significant needs of patients across multiple therapeutic areas."
Reed's comment echoes statements made by Roche executives several years ago when the company first set its sights on RNAi, viewing it as — in the words of former Head of Roche Global Pharma Research Lee Babiss — "one of the most promising approaches to tomorrow's healthcare technology" that has the potential to "target complex diseases."
In 2007, Roche inked a sweeping deal to acquire non-exclusive access to Alnylam Pharmaceuticals' technology in oncology, respiratory diseases, metabolic diseases, and certain liver diseases. Under the arrangement, Roche gave Alnylam $274 upfront, paid $15 million for its German unit, and bought $42 million in the RNAi firm's stock.
A year later, Roche shelled out $125 million to acquire Mirus Bio, primarily for its polymer-based dynamic polyconjugate siRNA-based delivery technology.
Unsatisfied by its progress with the gene-silencing technology, in 2011 Roche backed out of the RNAi space amid a broader corporate reorganization, eventually selling off its RNA therapeutics assets to Arrowhead Research for a 10 percent equity stake worth about $3.6 million at the time and the promise of milestones and royalties on future drugs.
Under the leadership of Reed, however, Roche has been taking another look at RNA medicines, notably through a collaboration formed in early 2013 with antisense leader Isis Pharmaceuticals on new treatments for Huntington's disease.
But Roche, the spokesperson stated, sees LNAs as holding even more potential than conventional antisense molecules. LNAs — essentially nucleic acid analogs in which the ribose ring is locked by a methylene bridge connecting the 2'-O atom with the 4'-O atom —"can be shorter and smaller than earlier siRNA and antisense DNA molecules while having higher affinity for their targets.
"Without the need for a complicated delivery mechanism, this emerging class of medicines opens new opportunities to address previously undruggable targets and may finally offer solutions for patients across many of our therapeutic areas including oncology, ophthalmology, neurosciences, infectious diseases, and rare diseases," the spokesperson added.
While Santaris has primarily developed LNAs as messenger RNA-targeting molecules, the company has also explored their utility as microRNA antagonists. Already, the firm has an miR-122-inhibiting compound called miravirsen under Phase II development for hepatitis C, and has been exploring the potential of short, eight-nucleotide-long "tiny LNAs" to target other miRNAs.
It is not certain whether Roche has any interest in miravirsen, especially considering the recent approval of a number of highly effective HCV treatments by other firms, or Santaris' other miRNA programs. The Roche spokesperson stated these miRNA efforts are under evaluation.