Startup Homology Medicines Launches With $43 Million Series A, To Be Led By Three Former Shire Execs

Startup Homology Medicines Launches With $43 Million Series A, To Be Led By Three Former Shire Execs May 2, 2016
By Mark Terry, Breaking News Staff

Lexington, Mass.-based Homology Medicines launched today with a $43.5 million Series A preferred stock financing. The round was co-led by 5AM Ventures and ARCH Venture Partners. They were joined by Temasek, Deerfield Management, and ARCH Overage Fund.

In addition to the funding, Arthur Tzianabos will join the company as chief executive officer, Sam Rasty, will be chief operating officer, and Albert Seymour will be chief scientific officer.

Tsianabos spent nine years at Shire , where he was actively involved in the development, approval and launch of drugs for rare genetic disorders. Rasty was also at Shire as vice president and head of new products at the company’s Rare Diseases Business Unit. Seymour was previously senior vice president and global head of research and nonclinical development at Shire.

Homology Medicines will focus on a new gene editing technology, which the founders claim are a better version of CRISPR-Cas9. None of the company’s work has been published, although one of the company’s investors indicates it will publish findings soon.

Currently there are three primary types of gene editing, and CRISPR-Cas9 is considered the easiest to use. Gene editing allows scientists to make genetic changes in almost any living thing, which is very practical in research settings, but has significant potential in treating genetic diseases. CRISPR-Cas9 hasn’t made it to human trials yet, but is being developed by Editas Medicine, Intellia Therapeutics and CRISPR Therapeutics.

Another type of gene editing is called zinc finger nucleases, which is being utilized by Sangamo BioSciences . Sangamo is using the technology in a Phase II trial to treat HIV, and will soon be starting two more trials, one in hemophilia B.

Another type of gene editing is TALEN, which is slated to be tested in a clinical trial this year by Pfizer and French company Servier in leukemia.

Homology claims its method will have advantages over gene editing and gene therapy, and is currently being dubbed homologous recombination. In homologous recombination, a chromosome swaps one short sequence of DNA for another similar one. A chromosome is a tightly coiled structure of DNA and certain proteins. In normal humans, there are 46 chromosomes, 23 matching pairs inherited from each parent.

Tzianabos told Xconomy that the company plans to use the technology to “flip in a gene that’s normal for a gene that’s abnormal.” It’s similar to gene therapy, in that Homology will engineer a section of “healthy” DNA, load it into an adeno-associated virus (AAV), which is commonly used in gene therapy.

In gene therapy, the AAV slips into the cell and expresses the protein the new DNA section is programmed for, until the cell dies. Homology’s approach differs in that the AAV enters the cell, releases its engineered DNA, which then changes places with the faulty gene. Then, if the technology works, when the cell divides, the two new cells will have the healthy gene, not the problematic one.

Dana Carroll, a geneticist at the University of Utah, speaking with Xconomy, points out that the concept isn’t new, but there are advantages and disadvantages to this approach. One of the advantages is there’s less risk of the gene editing creating unanticipated mutations in the target DNA. The biggest problem, however, is efficiency and getting the desired gene swap in a volume to generate enough healthy cells and proteins.

Tzianabos says the efficiency issue is marked by the company’s “big leap,” which is AAVs discovered by Saswati Chatterjee, a virologist at the Beckman Research Institute at the City of Hope in California. Chatterjee is the scientific founder of Homology. ”The kind of efficiency rates we’re seeing will allow us to translate into something that we believe is going to be clinically meaningful for patients.”

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