Selecta Biosciences started up six years ago with a plan to use nanoparticles to make customizable vaccines. Along the way, however, the Watertown, MA-based company found a potentially lucrative niche for its technology—helping to make other biologic drugs on the market safer. Today, it’s cashing a big check from a group of its venture backers to go prove it in clinical trials.
Selecta is announcing today that it’s raised more than $20 million in new financing, bringing the total its raised since its 2008 inception to $78.6 million. The latest cash comes from all of Selecta’s existing investors (Polaris Partners, Flagship Ventures, OrbiMed Advisors, NanoDimension, Rusnano, and Leukon Investments) and three new ones (I2BF, Eminent Venture Capital, and an undisclosed backer), according to CEO Werner Cautreels.
The funds will help Selecta bankroll an effort to prove that its nanoparticle vaccine technology can neutralize the unwanted immune responses that can render some biologic drugs ineffective, or worse, trigger severe allergic reactions in patients—what’s referred to as “immunogenicity.” Selecta is trying to show this, initially by souping up an old gout drug—pegsiticase—that has had immunogenicity problems in the past. The new program, SEL-212, will begin its first clinical trial next year.
Selecta believes that if it can prove its case in the clinic, it could set the stage for partnerships with pharma and biotech companies that would be interested in improving marketed protein drugs with issues causing immune reactions. Cautreels notes this type of strategy could apply to enzyme-replacement therapies, Factor VIII infusion therapies for hemophilia, or even gene therapies.
That plan is the latest step in what Cautreels calls a “gradual” strategic evolution for Selecta. The company was formed from the work of MIT professor Bob Langer and physician-scientists Omid Farokhzad and Ulrich von Andrian, both of Harvard Medical School. The big idea is to produce vaccines from biodegradable, polymer nanoparticles that can be custom-built (out of “select” ingredients) to have the same size and shape of specific viruses.
Those vaccines are supposed to selectively target a subset of white blood cells (antigen-presenting cells), and elicit more powerful immune responses than traditional vaccines while limiting side effects. Traditional vaccines, by comparison, are typically made with deactivated viruses that cause the immune system to build up a defense to a specific pathogen should it invade the body later on.
Selecta identified a few different potential ways to utilize the technology. One was to make vaccines to help prevent certain diseases (like malaria), or therapeutically treat existing ones (such as cancer, infections, or even smoking addiction). But the company has found that the best way for it to stand out is to focus on “antigen-specific tolerance,” or, using its technology to tell the immune system to call off an unwanted attack—like when the body recognizes a protein drug as a foreign invader, and whips up antibodies to fight it (or, in the case of type 1 diabetes, when the body attacks its own beta cells).
So while Selecta is still developing some conventional vaccines, it’s only doing so through partnerships and non-dilutive grants. The company is instead pouring its venture dollars behind the idea of creating a niche for itself: preventing those unwarranted immune system attacks.
“[That’s] where we are really unique and on the forefront,” Cautreels says. “This is also the space with the highest medical need [and] where we have the highest interest for potential collaborations.”
Selecta has identified some 30 drugs on the market already that have a high prevalence for these anti-drug antibody attacks. Its goal is to form partnerships with the companies making those drugs (or others in development) to add its technology, and reduce the risk of those immune reactions. That would provide Selecta with a quicker, more cost-effective way to generate revenue than trying to develop its own vaccines internally.
That’s the plan, anyway. Now Selecta has to show its technology can get rid of a drug’s immunogenicity. To prove its case, Selecta homed in on uricases, which are enzymes that gobble up uric acid. In instances of gout, uric acid builds up in the blood, leading to a type of painful arthritis. Patients are first typically given drugs that block the production of uric acid like allopurinol, but those treatments don’t work for everyone.
To fill the void for people that fail those initial therapies, a few companies have tried to engineer recombinant uricase to digest the excess uric acid. That’s been tough, Cautreels says, in part because of the immunogenicity associated with the approach. One company, Bridgewater, NJ-based Savient Pharmaceuticals, won FDA approval of such a drug, called pegloticase (Krystexxa), in 2010. For various reasons, its launch was a flop, then last year Savient went bankrupt and sold the drug to Crealta Pharmaceuticals. Another company, EnzymeRx, tried to develop a similar-type drug, pegsiticase. Cautreels says the drug never made it because of “expected immunogenicity,” and further, that similar issues have limited pegloticase’s use. EnzymeRx sold its drug to China-based 3SBio in 2010 for just over $6 million.
Selecta sees those past issues as opportunities. Thinking its technology can effectively fix pegsiticase, the company bought rights (except in China) to the drug for an undisclosed sum in June. The souped-up pegsiticase prospect is called SEL-212, and will begin its first trial next year. In many ways, that trial will determine whether Selecta’s strategic plan really holds water, because it will offer proof of its technology’s value in human patients.
“The gout product by itself will be very compelling, but that’s only the beginning because [if it works], now the platform opens up,” Cautreels says.
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