Selecta Biosciences, a Bob Langer Creation, Raises $15M For Nanoparticle Vaccines

Xconomy Boston — 

Boston’s prolific bioengineering professor, Bob Langer, is at it again. Selecta Biosciences, the Watertown, MA-based vaccine developer with ties to the Langer lab at MIT, has raised another $15 million in venture capital to make nanoparticles that it says are the key ingredients in a new generation of more effective vaccines.

Selecta collected the cash, its Series C round, from a new lead investor in OrbiMed Advisors, as well as existing backers Polaris Venture Partners, Flagship Ventures, NanoDimension, and Leukon Investments. This latest shot of cash—which Selecta didn’t actively solicit—comes in addition to a $15 million round the company pocketed back in February 2009. All this cash means that Selecta now has enough money to run through 2012, while speeding up its plans to test its platform technology.

What’s the big idea attracting all this investment? It’s all about tiny particles. Selecta is developing biodegradable polymer nanoparticles that can be self-assembled at low cost, and at a large commercial scale, Langer says. These particles can be made in the same size and shape of a virus, which looks like a foreign invader to the immune system.

But that’s only half of the equation. Selecta’s particles can be designed to specifically target a type of white blood cell, antigen-presenting cells, that are critical for exposing bits of pathogens to both B and T cells of the adaptive immune system. Vaccines of old haven’t had the potential to be aimed this specifically, or made to be this potent. Selecta’s method could be applied to vaccines that prevent infectious disease, or those that mount a therapeutic immune response to ward off an existing disease. The new method doesn’t require any weakened forms of virus as a delivery vehicle, which means the new vaccines have potential to be safer, Langer says.

“We haven’t seen anything like it,” Langer says.

Bob Langer

Bob Langer

Langer, of course, isn’t doing this all by himself. Selecta’s executive chairman is Bob Bratzler, the former CEO of Coley Pharmaceutical Group, the cancer immunotherapy company that was bought by Pfizer in November 2007. Omid Farokhzad of Harvard Medical School is a co-founder, and the board includes George Siber, the former chief scientific officer of Wyeth Vaccines—the company that developed the blockbuster pneumoccocal vaccine for infants (Prevnar). OrbiMed’s Carl Gordon is joining the Selecta board in connection with the financing.

Selecta is still awfully coy in public about what it plans to do with the new money. Bratzler wouldn’t say what the company’s lead vaccine candidate is designed to treat, or whether it will be a therapeutic or prophylactic vaccine. Animal tests have shown that Selecta’s method can stimulate a prolific antibody response, which translates into high rates of effectiveness. The company does say that its first clinical trial is scheduled to begin in 2011.

This idea of specifically engineered vaccines sounds similar to a Seattle-based company called Immune Design, which is backed by Versant Ventures, Alta Partners, and The Column Group. The company is making synthetic adjuvants—compounds that boost an immune response to vaccines—while specifically targeting them to antigen-presenting cells using a viral delivery mechanism from David Baltimore’s lab at Caltech. One key difference, Bratzler says, is that Selecta doesn’t use the viral delivery mechanism.

“We’re the only company with a fully integrated synthetic vaccine approach,” Bratzler says.

While that may not matter much in early demonstration projects, the Selecta approach is thought to have advantages for a commercial product, Langer says. By using the biodegradable nanoparticles that can self-assemble, the vaccine compounds are easy to manufacture. The Selecta vaccines also ought to be easy to handle and transport, potentially through freeze-dried packaging, Langer says.

The high degree of potency also allows Selecta to think about different ways of delivering the vaccines, Bratzler says. It’s possible that some vaccines that currently require multiple booster shots could be given in a single shot. Selecta is also thinking about topical delivery through the skin, and through mucosal membranes that line nasal passages, he says.

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