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One day after the release of a Nature Medicine paper warning of the potential hazards of testing CRISPR-Cas9 gene editing in humans, Homology Medicines, a startup advancing a different genetic surgery technique, has just grabbed a big round of funding to make its own clinical push.

Homology, of Bedford, MA, wrapped up an $83.5 million Series B round this morning. A wide group of investors led by Deerfield Management provided the funding, bringing the companys total amount raised to a whopping $127 million since it was formed last year.

Homology is making the bold claim that its underlying science, technology it calls AMEnDR, is a better version of existing gene editing methods, among them the CRISPR-Cas9 technology that has taken the scientific research world by storm and has led to the formation of three now publicly traded companies, Editas Medicine (NASDAQ: EDIT), Intellia Therapeutics (NASDAQ: NTLA), and CRISPR Therapeutics (NASDAQ: CRSP).

CRISPR gene editing is a two-part biological system that researchers can use to help irreversibly alter DNA. The three companies are involved in a high-stakes race to use the technology to develop human therapeutics, with the first clinical trials expected to begin next year. Yet one of the fears involved in bringing the technology to human trials is the possibility of off-target effectsa genetic surgery error that causes irreparable damage, like cancer. One of the fields pioneers, Feng Zhang of the Broad Institute of MIT and Harvard, just co-authored a paper in Nature Medicine urging caution about the rush to move forward. Zhang and colleague David Scott argued that researchers should analyze patients DNA before giving them CRISPR-based drugs, citing the myriad differences between each persons genetic makeup.

Homology isnt using CRISPR, like its publicly traded rivals. Instead, its recreating a natural biological process known as homologous recombination, which cells in humans and other species do to repair DNA damage or, in the case of bacteria, to improve their genetic diversity. In homologous recombination, one chromosome essentially swaps one short DNA sequence for another similar one. Homology aims to engineer a piece of healthy DNA, pack it into a type of adeno-associated virus, or AAVa delivery tool commonly used in gene therapy and gene editing technologiesand infuse it into the body. The virus carrying the DNA locks on to the cell that needs a genetic fix, enters it, and releases its DNA payload. The healthy DNA then swaps places with the faulty gene inside the patients cells. If and when the cells divide, the new cells would carry the fixed gene, not the faulty one. One potential benefit of this approach is there may be less likelihood of an off-target error, like mutations in the target DNA that cause cancer, than with CRISPR.

Thats the hope, but the technology hasnt been tested in humans as of yet. With the new cash, however, Homology is getting a shot to try. In a statement, Homology CEO Arthur Tzianabos said the funding will help Homology bring its first drug candidate toward the clinic, though he didnt specify how long that might take. The company is focusing on rare diseasesno surprise given Tzianabos, chief operating officer Sam Rasty, and chief scientific officer Albert Seymour all worked with one another at rare disease giant Shire (NASDAQ: SHPG). According to its website, the company will develop therapies for inborn errors of metabolism, and Duchenne muscular dystrophy and cystic fibrosis are among its potential targets as well. (Duchenne and cystic fibrosis are early targets of CRISPR-based medicines as well.)

Fidelity Management and Research, Novartis, Rock Springs Capital, HBM Healthcare Investments, Arch Venture Partners, Temasek, 5AM Ventures, Maverick Ventures, Vida Ventures, Vivo Capital, and Alexandria Venture Investments also took part in the funding. Heres more on Homology, and gene editing with CRISPR-Cas9.

Ben Fidler is Xconomy's Deputy Biotechnology Editor. You can e-mail him at bfidler@xconomy.com

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Homology Med Bags $83.5M More, Fueling Push For Gene Editing ... - Xconomy