Mirina, one of the intriguing startups hatched in the past couple years at Seattle-based Accelerator, has passed a key test that will allow it to live to fight another day. The developer of microRNA-based therapies has secured an undisclosed “expansion round” of financing that will allow it to operate another 12 to 15 months, according to Accelerator CEO Carl Weissman.
Versant Ventures, one of the original backers of Accelerator seven years ago, has jumped in to lead this additional round of financing for Mirina, Weissman says. Most of the usual Accelerator syndicate is joining in too—Alexandria Real Estate Equities, Arch Venture Partners, OVP Venture Partners, and WRF Capital. While this isn’t enough money for Mirina to spin out of Accelerator like some of its predecessors, Mirina will use the cash to keep testing its technology for making microRNA drugs, and it will have a chance to secure some new intellectual property around some surprising new pharmaceutical characteristics, Weissman says.
Mirina’s ability to secure cash is a reflection of how microRNA has emerged as one of the hottest concepts in biology since they were first discovered in humans about a decade ago. The idea is to create drugs that can inhibit specific stretches of RNA that regulate how networks of proteins are expressed. By hitting switches that control entire networks of proteins, scientists hope to have success against complex diseases like diabetes, cancer, and inflammation that involve activity of many genes and proteins. Hitting these networks may have more power against these complex conditions than more traditional approaches that tend to rely on specifically inhibiting a single gene or protein, scientists say.
MicroRNA still represents the bleeding edge of biological research, as no one has yet come close to FDA approval of a drug that works this way, and only one company, Denmark-based Santaris Pharma, is thought to have entered clinical trials. But a number of companies have sprouted up to take advantage of the concept, including Santaris, Carlsbad, CA-based Regulus Therapeutics, Boulder, CO-based Miragen Therapeutics, and Austin, TX-based Mirna Therapeutics.
The Accelerator’s bet on the space, Mirina, was founded in August 2008 with a license to a chemistry platform from Nanogen (now part of France’s Elitech Group) which it believes allows for more potent microRNA-inhibitors than the rest of the pack,Weissman says. Accelerator is known for keeping its startups on a short leash, insisting they hit specific milestones in their first 18 to 24 months. While Mirina hasn’t hit all of them, it has produced such compelling evidence on a couple of counts, and shown some upside surprises, that it enticed investors to keep it going. The company has shown it can make its oligonucleotide drugs, and that they are potent and specific for certain microRNA regulatory switches. Now it wants to know how well that can be applied to certain models of disease.
“This is spectacular,” Weissman says. “The chemistry has some new and unexpected properties that will differentiate it in more ways than just potency, compared with everybody else out there.”
Weissman declined to be more specific about what those characteristics are, because Mirina is in the midst of trying to secure new intellectual property around them, he says.
If Mirina’s technology is really so hot, I wondered, why isn’t it “graduating” from Accelerator with a $20 million-plus round of venture capital like some of its predecessors, such as Allozyne, VLST, Theraclone Sciences? The big reason, Weissman says, is that Mirina doesn’t really need that much capital to invest in business infrastructure. It can stay lean—with just five employees at the moment—and still hit value-driving scientific goals as long as it relies on collaborations and business support from Accelerator, Weissman says.
Getting a small expansion round of financing isn’t going to keep Mirina going forever. Weissman noted, however, that this is a similar interim step that Allozyne and Theraclone Sciences followed before they eventually won bigger venture rounds.
Mirina is spearheaded by David McElligott, the vice president of R&D and a scientific veteran of Bothell, WA-based Icos. His team will be charged in the coming months with further developing the company’s microRNA technology platform, demonstrating its drug candidates have desirable properties in mice and other live animal tests, and further studying the unexpected new properties that the company is keeping secret for the time being. Mirina hasn’t published anything in the peer-reviewed literature, or talked at a scientific conference, and it won’t until it at least has its patent applications filed in the U.S., McElligott says.
As with any new mode of treatment, there is huge risk when venturing into the unknown. It’s entirely possible that shutting down entire networks of proteins could throw a wrench into essential biological functions, and cause dangerous side effects. While the heat is certainly on for Mirina and its peers to gather evidence from animals—and people—to prove the microRNA concept, the safety of these drugs will have to monitored with great care. That’s balanced out, McElligott says, by the potential of a new paradigm for addressing some of the most common diseases that have traditionally been very tough to treat, things like neurodegenerative diseases, and cancer.
Traditional research has often focused on making small-molecule chemicals that are increasingly specific to a given target, to avoid hitting similar protein structures, which can lead to “off-target” toxicity. MicroRNA research, in a sense, seeks to turn that notion on its head, arguing that many drugs are such rifle-shots at a specific target that they aren’t powerful enough to silence the chaos created by diseases that arise from an entire symphony of things going wrong inside cells.
“Hitting a target with one drug isn’t always beneficial, and making single molecules increasingly selective isn’t always for the best,” McElligott says. “Sometimes you need to hit multiple components to get the best outcome.”
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