Xconomy - Excellent Review of Competitive Landscape in Sickle Cell

http://www.xconomy.com/national/2015/08/18/100-years-but-only-one-drug-sickle-cell-patients-wait-for-help/

Sangamo Excerpt:
Another gene editing program for sickle cell is in the works from Sangamo Biosciences (NASDAQ: SGMO) of Richmond, CA. Sometime in the second half of 2016, Sangamo and its development partner Biogen (NASDAQ: BIIB) will ask FDA permission to start human trials with its program.
To do its gene editing, Sangamo uses a system called zinc finger proteins, which it owns. No one else can use zinc fingers without a license, and Sangamo, with 20 years of development under its belt, is the only company to advance a gene-editing product into human trials, for HIV.

CRISPR Excerpt:
CRISPR/Cas9 hasn’t been around as long as zinc finger proteins, and the technology has a major hurdle to overcome: making sure the molecular “scissors” it uses are making DNA cuts in the right places. Right now, the methods used to detect off-target cuts simply aren’t sophisticated enough. And all it takes is one cut in the wrong place to trigger a tragic unintended consequence. The fear dates back to gene therapy experiments fifteen years ago, in which genes meant to heal kids with severe combined immunodeficiency—the so-called “bubble boy disease”—inserted themselves in the wrong place and triggered cancer. Being more precise with gene editing tools, like CRISPR/Cas9, is still a goal, not a reality.
“Our ability to find off targets isn’t great right now,” says Corn. “No matter how bullish you are, the field [of gene therapy] has been bitten by kids getting leukemia. That should keep everyone in the hematopoietic field up at night.”