By Doug Macron
Mirna Therapeutics this week announced that it has received a $5 million funding commitment from Texas through the state's Emerging Technology Fund, which the state government established to help companies develop new technologies.
The ETF award, $2.5 million of which Mirna has already received, "is a catalyst for advancing our microRNA mimic-discovery platform and a robust pipeline of promising drug candidates” Mirna President and CEO Paul Lammers said in a statement.
Importantly, Mirna expects the money will help it meet its goal of filing two investigational new drug applications in the second half of 2011, Lammers told RNAi News.
According to Lammers, the ETF funding will be provided in two, $2.5 million tranches, the first of it received in November 2009. The second is expected to be awarded in June.
As detailed in the grant application, Mirna said it plans to use the money to lay the groundwork for its two lead drug candidates, mimics of miR-34 and an undisclosed miRNA, both of which are involved in down-regulated in cancers.
The work will involve "finalizing the chemistry of our lead microRNA mimics, getting into pre-IND-enabling toxicity studies in 2010, and [filing] INDs for our lead candidates in the second half of 2011," he said. "Then, [we aim to] initiate our first clinical trial in oncology in late '11 or early '12."
Lammers said that the miR-34 mimic, called miR-Rx34, continues to be Mirna's lead candidate "because we have a ton of data on that mimic."
Indeed, last summer the company said that preclinical data showed miR-Rx34 inhibited the proliferation and viability of a "variety of cultured cancer cells, including those derived from patients with melanoma, lung, prostate, liver, and colon cancers" (see RNAi News, 6/18/2009).
Additionally, the data showed that miR-Rx34 inhibited the growth and metastasis of established human tumors when delivered systemically to mouse models of lung and prostate cancer, the company's two primary indications of interest.
To Lammers, the ETF award will provide a measure of "breathing room" for Mirna, but he noted that it remains on the lookout for the additional funding needed to become a clinical-stage company.
"We think that it will take us about $15 million to get us into a phase I-type situation," he said.
"Right now, we're in capital-raising mode, but obviously the $5 million [grant] … allows us to take our time finding the right investors and/or deals that will allow us to [secure] the additional capital that will get us through" initial clinical studies.
Just how that $15 million will be obtained — whether from venture capital investment or from a bigger industry partner — is not yet clear, but Lammers indicated he was confident that Mirna is in a good position to close the deals.
"We're eyeing the first half of this year for making it happen," he said. "We're meeting with a number of companies and have engaged a boutique investment advisor firm … to help us in this effort."
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Currently, there are "a lot of folks that are interested in the microRNA space," including "pharma venture funds, which is a good sign," he added.
Still, Lammers conceded that the miRNA therapeutics space is in its infancy. And having watched the siRNA space for "quite a few years," potential partners and investors are well aware of issues such as efficiency of delivery, toxicity, and off-target effects.
As far as toxicity and off-target effects, Mirna may have an edge given that its therapeutic approach involves replacing miRNAs that are normally expressed, rather than down-regulating ones, potentially disrupting natural processes elsewhere in the body.
"Obviously, we see that [our mimics are] taken up by tumor cells and healthy cells, [and get] degraded as part of the normal machinery in the cells," Lammers explained. "If I put another 100 copies into a cell that already has 10,000 copies of this specific microRNA, it doesn't really matter so much. But [cells] that have an under-expressed microRNA truly need even those 100 or 200 copies that you bring in."
When it comes to delivery, Mirna is exploring two avenues. The first is a lipid emulsion technology that has been exclusively in-licensed from an undisclosed party, and which the company used in the in vivo studies it presented last year.
For the other approach, "we're working in a research collaboration with [an undisclosed] Japanese company to develop a nanoparticle delivery [vehicle] that they have used and has already been in humans," Lammers said. "We're currently doing in vivo experiments to see if we can further optimize it.
"We will make a decision in the next few quarters about what we're going to do delivery-wise and which route we're going to take," he added. "I don't want to re-start a program later on, and I want to make sure we have one that is safe, non-toxic, and gets the microRNA to the target."
Meanwhile, Mirna is also considering growing its staff, not only to meet the ETF requirement that award winners increase the number of technology jobs in Texas, but also to bring in-house the capabilities needed to oversee pre-IND research and, ultimately, clinical studies.
As such, "we're looking to add a few positions … and grow this company in a reasonable fashion," he said, adding that Mirna's current eight-employee roster could increase to about 12 over the course of 2010.