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Gilead Gains Genome-Editing Hepatitis B Therapy

Hepatitis-B virus

Hepatitis-B virus (, Pixnio)

13 September 2018. Biopharmaceutical company Gilead Sciences is acquiring a genome-editing technology for treating hepatitis-B, a viral disease affecting the liver. The deal is expected to bring Precision Biosciences in Durham, North Carolina, developer of the technology, at least $445 million if all parts of the agreement are fulfilled.

Hepatitis-B is a life-threatening viral infection of the liver, which if it becomes chronic, can cause cirrhosis — scarring of liver tissue — and liver cancer. The hepatitis-B virus is spread through blood or contact with other bodily fluids, such as from mother to child in pregnancy. World Health Organization says hepatitis-B is a global public health problem affecting some 257 million people now living with the disease and causing some 887,000 deaths in 2015. Another problem with hepatitis-B is there are few, if any, immediate symptoms of the disease, and it can go undetected for decades. While a vaccine is readily available to prevent hepatitis-B, there are now no complete cures.

Precision Biosciences offers a genome editing system called Arcus for medical and agricultural applications using its own synthetic enzymes. The company produces these synthetic enzymes, known as homing endonucleases to zero-in on specific DNA sequences, usually those with long strings of 12 to 40 base pairs that occur on rare occasions in the genome. The enzymes are small in size, says the company, making them precise editing tools, minimizing off-target breaks. Its homing endonucleases, says Precision, can also perform various editing tasks at the target site, including insertions and edits as well as deletions.

Gilead and Precision say current treatments suppress replication of the hepatitis-B virus, but do not clear the virus from the system. For the virus to replicate and advance the disease, the virus forms a closed circular DNA pattern, which Precision says can serve as the target for its genome-editing enzyme. The company says tests at Gilead’s lab show its genome-editing enzymes can target this circular DNA, including when integrated with human liver cells.

According to the agreement, Precision will be responsible for identification, development, and preclinical testing of enzymes for editing hepatitis-B viral DNA. While the deal does not have an upfront payment, Gilead will fund all research and development of these enzymes, and be responsible for clinical studies and commercialization. Precision will be eligible for milestone payments under the agreement totaling $445 million, as well as subsequent royalty payments on sales of products from the collaboration.

Gilead Sciences, in Foster City, California is developing biologic treatments for a wide range of disorders, including a treatment for the hepatitis-B virus, or HBV, currently in early-stage clinical trials as well as other liver diseases. Derek Jantz, Precision’s chief scientist, says in a joint statement, “Precision is pleased that initial studies with our Arcus platform have established an important role for genome editing in their HBV program. This is an excellent application for our technology, which has made notable progress toward therapeutic in vivo editing in relevant models over the last year.”

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