Sangamo up 17% on HIV therapy news

Sangamo Biosciences shares jumped 17 percent Thursday as the Richmond biotech company continued to enjoy the glow of positive news surrounding its promising gene therapy to treat HIV, the virus that causes AIDS.

Astudy recently published in the prestigious New England Journal of Medicine touted the treatment’s promising performance in a small trial with 12 HIV-positive patients. The news drove up Sangamo’s stock $3.35 to close Thursday at $22.96 per share.

Gene therapy consists of modifying or correcting human genes and introducing them into the body. Sangamo’s own tech-

nology engineers a class of proteins — zinc finger DNA-binding proteins — to make other proteins that can edit DNA sequences and turn genes on or off.

For such a gene therapy to work on a wide scale, companies must develop a single injection, said Dr. Warner Greene, director of the Gladstone Institute of Virology and Immunology in San Francisco.

But “if we could achieve a true cure for HIV by definition, we would be getting people off of their anti-HIV medications, which would be a huge, huge advantage,” he said.

While the therapy still needs to undergo larger clinical trials and secure a host of regulatory approvals, a process that could take more than a decade, Sangamo currently holds a lead in the race to replace chronic drug treatment with gene therapies. The 85-employee company is also working to apply the technique to hemophilia and other genetic diseases.

Amilestone

“The publication of this study in the New England Journal of Medicine represents a milestone in the development of (zinc finger nuclease)-mediated genome editing as a new therapeutic approach,” Sangamo CEO Edward Lanphier said in a statement. “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.”

For the study, doctors injected a dozen patients with millions of immune cells reprogrammed by Sangamo to block a protein receptor that makes such cells vulnerable to HIV.

Doctors later took six patients off antiretroviral drugs. In four patients, the virus stayed at a stable level or decreased without drug therapy for at least 12 weeks.

Mixed effects

The treatment had mixed effects — one patient badly reacted to the transplant — but experts see the treatment as a first step for a therapy that someday could replace the drugs, which suppress but do not eliminate the virus.

Many patients see these drugs, which they must consume every day, as burdensome and costly. Sales of antiretroviral drugs in the United States and the five biggest markets in Europe reached $13.3 billion in 2011, according to Datamonitor.

Sangamo hopes the genetic therapies can treat other diseases such as hemophilia, a rare disorder in which blood does not clot normally. The company plans to apply for clinical trials this year.

Huntington’s disease

Sangamo is also focusing on Huntington’s disease, a neurologic disease without a treatment or cure, and sickle cell disease, a genetic blood disorder. Last October, Sangamo acquired the San Diego company Ceregene and its gene therapy for Alzheimer’s disease. Researchers are currently tracking a group of patients given the treatment and plan to present results next year.