NEW DRUG FOR TB

Bayer AG's Avelox, set to become the first new type of medicine for tuberculosis in 30 years, may shorten treatment time by two months and slow the development of deadly, drug-resistant strains. Combining the antibiotic with three other therapies might cure the disease in four months instead of six, according to research funded by the Gates Foundation and the U.S. government. As a result, the number of patients who stop treatment too early may fall, slowing the spread of a disease that infects about 2 billion people, scientists say.
TB approval for Avelox, already used to treat pneumonia, may help contain lethal multidrug-resistant TB, the germ carried by Atlanta lawyer Andrew Speaker when he boarded a flight to Paris in May. Doctors at an infectious disease meeting this week in Chicago will hear results of a clinical trial. The findings will be crucial to the drug's approval as early as 2011.
The chemical structure of the drug, also known by the generic name moxifloxacin, can attach to both fatty and watery molecules, allowing it to penetrate TB efficiently, he said.
The Seattle-based Gates Foundation, the world's largest charitable fund, has given $140 million to the Global Alliance to develop new TB drugs. Without that support and direction, along with funds from the U.S. Food and Drug Administration for trials of Avelox, new TB drugs would never get approval, public researchers said. The market is small and treatment trials are so expensive and lengthy that most companies won't touch them.
Most patients carry TB in a dormant, non-infectious form. Even when active, the germ grows slowly, dividing about once a day, compared with other bacteria that might replicate every 20 minutes. The plodding pace gives antibiotics few opportunities for bacterial sabotage, and the organism also has a fatty outer coat that keeps most drugs out entirely.
Multi-drug resistant TB affects about 400,000 people worldwide. Speaker, the lawyer who put hundreds of airline travelers at risk of exposure by taking transatlantic flights, underwent surgery in a Denver hospital to remove infected tissue. Public health officials have spent decades trying to find the best ways to make sure TB patients finish their typical six- month treatments, which once lasted at least 18 months. Skipping doses allows resistant strains to thrive and spread to other people, said David Ashkin, the tuberculosis controller for Florida. Ashkin confines dozens of TB patients to a secure hospital in Lantana annually to make sure they take all their drugs and don't spread germs.
`Six months of therapy is very hard for some patients, with a shorter regimen, more people might complete therapy.'' About a third of patients drop out in the final two months of treatment, the TB alliance's Spigelman said. His group will use Gates Foundation support to begin testing four-month treatment with the Bayer drug later this year. He plans eventually to test whether other drug combinations can beat TB in three months or even two.
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