Gilead Partners with Precision Bio in Search of Gene-Editing HBV Cure

Xconomy San Francisco — 

Gilead Sciences is turning to gene editing in its effort to develop a cure for hepatitis B virus infections—DNA-cutting enzymes that would eliminate the virus in the body, something current hep B drugs can’t do.

Foster City, CA-based Gilead (NASDAQ: GILD) is partnering with Precision Biosciences, a company that has used its proprietary gene-editing platform to develop products for both agriculture and human health. No upfront payments were disclosed, but if the alliance results in commercialized drugs, Durham, NC-based Precision stands to gain up to $445 million in milestone payments and royalties. Under the agreement, Gilead will fund the research and development.

The hepatitis B virus (HBV) causes a liver infection that can develop into a chronic condition. Chronic HBV infection affects an estimated 850,000 in the U.S., though the Centers for Disease Control and Prevention says that the number affected could be as high as 2.2 million. The CDC notes that the introduction of HBV vaccination led to a decline in the number of cases since the 1990s, but adds that the number has at times increased since 2012.

There are now eight drugs FDA-approved to treat chronic HBV infection, three of them once-daily pills from Gilead. The list of approved treatments also include interferon injections, which can cause side effects such as autoimmune disorders. Gilead says that while current HBV treatments suppress viral replication, they do not completely clear the virus. The persistence of a type of viral DNA, called covalently closed circular DNA (cccDNA), in patients’ livers, enables the virus to replicate if treatment is stopped, leading to relapse the company says.

Gilead is hoping that Precision’s gene-editing technology, called Arcus, will lead to a cure.

In early lab tests, Gilead says Arcus’s DNA-cutting enzymes have been shown to target and destroy the DNA of the virus and the cccDNA in human liver cells. If this approach works in humans, the companies say it could mean the elimination of all traces of the infection.

According to the agreement, Precision will be responsible for taking experimental hepatitis B therapies through preclinical development; Gilead will handle clinical testing and commercialization, if the drugs are approved by the FDA.

Other companies are pursuing new HBV treatments. Last week, shares of Arrowhead Pharmaceuticals (NASDAQ: ARWR) reached a four-year high after the biotech released encouraging preliminary data from a Phase 1 study testing its drug, ARO-HBV. The drug, from Pasadena, CA-based Arrowhead, which maintains R&D operations in Madison, WI, is meant to silence all gene products from the virus. The company believes this approach will then allow the body’s immune system to clear the virus, effectively curing the infection.

While CRISPR gene-editing techniques may be better known, Precision’s Arcus technology has caught the eye of other large pharmaceutical companies. The company has an alliance with Shire (NASDAQ: SHPG) focused on developing cancer immunotherapies. And the North Carolina company is also working to bring its own gene-edited cancer cell therapy into clinical testing, an effort that’s supported with a $110 million Series B round of financing closed in June.

Here’s more background on Precision’s Arcus gene-editing platform.

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