With a few chemical tweaks and some dutiful protein partners, a new biotech from Flagship Pioneering thinks it has cracked the code to turn DNA into a brand-new class of therapeutics.
The Massachusetts venture firm today debuted Serif Biomedicines, a startup hoping to write a new chapter for DNA medicines that are safer and more accessible than gene therapies, with an initial investment of $50 million.
“We think this could be the first of a new category of medicine,” Jacob Rubens, Ph.D., Serif’s co-founder and CEO, told Fierce Biotech, akin to monoclonal antibodies, mRNA and RNA interference.
“When a foundational layer of biology becomes engineerable, new therapeutic categories are born that can redefine the possibilities for medicine,” Noubar Afeyan, Ph.D., founder and CEO of Flagship Pioneering and co-founder of Serif, said in an April 21 release. “Serif builds upon our experience in prior category-originating Flagship companies to establish Modified DNA as a practical and broadly applicable therapeutic platform.”
Flagship formed Serif in 2021, Rubens explained, with the goal to solve several problems that plague traditional gene therapy. Namely, the class of medicines provokes an immune response and is difficult to manufacture.
“DNA, when delivered via a gene therapy, is really a virus,” Rubens said, referring to the vectors used to carry the genetic material. Serif’s approach is to instead use modified DNA that is packaged inside of lipid nanoparticles. This DNA is accompanied by mRNA that, once inside the cell, is turned into proteins that shuttle the DNA into the nucleus, where it can itself be turned into a therapeutic protein.
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Engineering DNA into a new kind of drug candidate was no easy feat. Rubens estimates that the team tried thousands of different modifications to the molecule before settling on a formula that didn’t trigger the immune system. While Serif won’t be sharing more details until a later medical conference, Rubens told Fierce that the team uses circular DNA with certain chemical modifications.
“We have a single-stranded version and a double-stranded version,” Rubens said. “We’re not going to say exactly what those modifications are today, just because it’s something we’d rather keep close to our chest.”
It’s these modifications that inspired Serif’s name, which refers to decorative flourishes added to the ends of letters in certain fonts. The company currently has a team of around 50 employees, Rubens said.
The upcoming data include studies in primates that show “tolerability” and “functional and therapeutic effects” after systemic infusions of Serif’s modified DNA, according to the release.
With modified DNA, protein partners and cell-specific lipid nanoparticles all in place, Serif is ready to turn its tech into therapeutic programs once the scientific community has weighed in. Potential applications include protein replacement and in vivo T-cell engineering, Rubens said.
“We’re getting our scientific feedback from the community for the first time, and we don’t want to overpromise or under-promise exactly what the timeline will be,” the CEO said.
Part of Rubens’ preparations for launch has included building up manufacturing expertise and starting early conversations with potential pharma partners, he told Fierce. He anticipates Serif’s pipeline to include a mix of wholly owned and partnered assets.
“Partnerships are going to be an important part of our strategy,” Rubens said, inspired by other genetic medicine pioneers like Flagship’s Moderna and Alnylam Pharmaceuticals, whose founding, CEO John Maraganore, Ph.D., is now an advisor to Serif.
