As the news emerged of Richmond, CA-based Sangamo Biosciences’s progress toward a gene therapy treatment for HIV infection, the media buzzed and investors boosted the company’s share price by 17 percent Thursday.
For the first time, Sangamo (NASDAQ: [[ticker:SGMO]]) had tried its gene-editing platform on human subjects, and it found encouraging signs in small early stage trials that the treatment could be adapted to push down the population of HIV virus to low or even undetectable levels.
The grabber in the story is that such a treatment might someday allow HIV-infected patients to stop taking antiviral drugs daily for the rest of their lives—eliminating both side effects and a big expense for the healthcare system.
So it’s natural to wonder how such developments would affect the companies taking in billions of dollars a year from sales of those HIV drugs.
The improved prospects for an HIV “functional cure” might have led some investors to turn around and shed shares in Foster City, CA-based Gilead, the world’s largest maker of HIV drugs, whose share price dropped more than 3 percent to $79.92 on Thursday and lost a bit more ground to wrap up the week at $79.58 on Friday. Antiviral drugs made up $9.34 billion of Gilead’s $10.8 billion in product sales in 2013. Gilead’s slide coincided with an overall decline in biotech indexes. It also came amid news from a Boston HIV/AIDS conference, including data from other HIV drug developers as well as Sangamo, that may have affected trading.
But some investors who have been closely following Gilead might have seen the price dip as an opportunity to snap up more shares in the company, which is also one of the industry’s most broad-based and well-funded new developers of cancer therapies.
While Gilead has continued to nurture its HIV and antiviral franchise—in December it gained FDA approval of the new chronic hepatitis drug sofosbuvir (Sovaldi), and won expanded FDA approval of its once-daily HIV combination drug, Complera—the company has also been buying up oncology companies and assets since at least 2010. And the acquisitions are beginning to bear fruit. Gilead announced in October that a late-stage trial of one of its leading cancer compounds, idelalisib, was halted early because the drug was already showing significant efficacy as a treatment for chronic lymphocytic leukemia. Even with last week’s price dip, Gilead shares are still up more than 75 percent over the past 12 months.
Gilead’s forward-looking moves to become a diversified pharmaceutical company may insulate it from an erosion of HIV drug revenue—if and when an effective gene therapy becomes approved, and accessible. Sangamo’s promising results came from tiny, early stage trials, and the company has said it needs to refine its ZFN gene-editing treatment procedures in future studies to enhance the chance of a cure.
But Sangamo’s moment in the spotlight is one recent reminder that gene therapy is finally emerging as a viable technology that could transform the treatment of HIV, cancer, and a host of other conditions. If the method proves out, it could shoulder aside some maintenance drug therapies by attacking genetic mechanisms closer to the root causes of a range of diseases. Sangamo is trying to do this with its proprietary toolkit of zinc finger proteins for altering the sequences of targeted genes. ZFN stands for zinc finger nucleases, which are molecular tools for homing in on specific small sections of genes and clipping them out.
“Our goal is to use this powerful technology to engineer genetic cures for diseases that have thus far been treated as chronic conditions, including HIV and a wide range of monogenic diseases,” said Sangamo CEO Edward Lanphier in a company release on the first of several studies unveiled this week.
The first paper, published in the New England Journal of Medicine on Wednesday, detailed the results of Sangamo’s inaugural trial of its ZFN gene-editing platform in HIV patients. Through genetic engineering of blood cells called T-cells, Sangamo is trying to mimic the natural immunity to a common HIV strain that a few rare individuals are fortunate enough to inherit with their own genes.
To create its treatment, Sangamo disabled a gene called CCR5 in T-cells from blood samples withdrawn from 12 HIV-positive trial participants. In most people, the CCR5 gene makes the cells susceptible to HIV infection. The modified T-cells with disrupted CCR5 genes were then infused back into the trial subjects.
In such Phase I trials, the first goal is to establish that previously untested treatments are safe. Sangamo reported that its treatment, called SB-728-T, was
