« on: August 04, 2010, 05:11:34 PM »
A 17-year-old Cambridge biotechnology firm is betting $35 million in new financing on the success of its budding gene therapy program.
This spring, Genetix Pharmaceuticals reinvented itself as the developer of treatments for two rare and devastating genetic disorders.
Left untreated, both diseases — the blood disorder beta-thalassemia major and the brain-wasting disease Adrenoleukodystrophy, or ALD — are fatal. And existing treatments can be as dangerous as the diseases.
Enter gene therapy. If it works safely, it will overcome current treatment risks, providing effective, enduring care.
Gene therapy has advanced substantially since 1999, when it gained notoriety after an 18-year-old named Jesse Gelsinger died in a research study. Recently, gene therapy has been shown to be effective in a handful of small human trials.
“I think that things have changed pretty dramatically for gene therapy over the last couple of years,’’ said Dr. Katherine A. High, an investigator with the Howard Hughes Medical Institute and director of the Center for Cellular and Molecular Therapeutics at Children’s Hospital of the University of Pennsylvania. High has acted as a consultant to Genetix. “I think that this is a good time to be getting into gene therapy, from a company’s standpoint.’’
High and Dr. Stephen A. Sherwin, chairman of BIO, the biotechnology industry’s national trade organization, both compared gene therapy to the development of monoclonal antibodies. It took two decades for monoclonal antibody therapy to advance enough to help patients. Now, there are dozens of monoclonal antibody drugs for diseases from cancer to rheumatoid arthritis.
“I believe that same story, however unlikely it might look to some today, will be told in due course for gene therapy,’’ said Sherwin, who does not have a financial interest in Genetix.
The premise of gene therapy is that well-functioning genes can be substituted for missing or mutated ones — producing the crucial protein the patient is lacking.
Because viruses are so good at getting around cellular defenses, these replacement genes are delivered to affected cells via a virus.
But those viral vectors have been tricky to manage. They triggered a fatal immune response in Gelsinger and have sparked leukemia in other patients.
But in recent years, researchers have developed viral delivery systems they believe can safely deliver replacement genes to cells that need them.
Genetix is using an HIV virus that has been defanged so it cannot cause AIDS, but will deliver the corrected gene. Called lentivirus, it can “infect’’ stem cells in the blood. When those cells divide to produce red blood cells, the corrected gene is passed on to its daughter cells and all future cell generations.
The virus itself dies, and researchers say it is a safe way to deliver drugs.
“If you are successful in getting enough genes into enough of those cells, you can have the presence of your therapeutic genes for the remainder of the life of the organism,’’ said Mitchell H. Finer, Genetix’s chief scientific officer.
Another viral vector, adeno-associated virus, or AAV, works better for cells that do not divide after early childhood, and is being tested by other companies in diseases of the central nervous system, including the eye.
Genetix’s therapy is done on a patient’s own cells — which are withdrawn, tinkered with, and reinserted — so there’s no risk the immune system will reject the fix. And because the virus is inserted into cells that have been removed from the body, it does not travel beyond the bloodstream once the cells are put back, Finer said.
So far, there have been no major side effects from the ALD treatment, which was first given to a 7-year-old boy three years ago, said Dr. Nathalie Cartier, the French scientist who led the study and is now a consultant to Genetix. The boy and two other patients who are about the same age are doing as well on the gene therapy treatment as they would have with the bone marrow transplant that is the standard of care for ALD, she said, but they were not good transplant candidates.
The major challenges facing Genetix, Finer and Cartier said, are demonstrating continued success in clinical trials, maximizing the amount of the corrected gene that gets into the cells, and developing a safe production process that can produce the therapy on a scale large enough to treat many more patients. “What it really comes down to is manufacturing and quality control,’’ Finer said.
Genetix’s president, Nick Leschly, said the new funding will allow the company to expand clinical trials already underway in Europe and to scale up production. Assuming all goes well, Leschly said, the gene therapy developed for these two diseases could work for many other genetic diseases.
“Just ALD and thalassemia alone more than justifies our investment,’’ he said. But “when you start looking at these other opportunities, then this is a giant platform.’’
Genetix’s original investors, TVM Capital, Forbion Capital Partners, and Easton Capital Investment Group, all contributed to the second round of financing.
New to this round were Third Rock Ventures, a Boston venture capital firm where Leschly is a partner, and Genzyme Ventures, a fund the biotechnology giant Genzyme Corp., of Cambridge, uses to invest in companies that work in its areas of interest.
Alan Walts, managing director of Genzyme Ventures, said his company decided to invest in Genetix because of the smaller company’s “innovative product for a very rare disease.’’
“The ultimate goal is that Genzyme would be able to be in a position to talk to the company about either a product license or an acquisition — whatever would be appropriate at the time,’’ Walts said.
“If the product works, if the trial is successful, we would love to have the opportunity to talk to them about commercializing the product.’’
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