This year began on an optimistic note for scientists, policy makers and those most affected by tuberculosis, with the licensing of a drug that represents the first new approach to treating the disease in more than 40 years. This year’s World TB Day gives us an opportunity to reflect on the progress we have made in confronting this ancient but persistent disease, as well as the challenges that remain. This year, with budget issues threatening the immediate future of medical research, the approval of a new tuberculosis treatment sheds light on the path ahead.
The newly licensed drug, known as bedaquiline or Sirturo, is important because it has shown promising results against tuberculosis that has become resistant to other treatment – often called multidrug-resistant (MDR) tuberculosis. I served on the [U.S. Food and Drug Administration] FDA advisory panel that recommended approval of the drug and I was happy that the agency concurred. However, we need not just one, but several new drugs to put together in successful combination if we are to avoid the mistakes of the past and avoid a future where tuberculosis is again a highly fatal, untreatable disease. Now is the time to put our foot on the accelerator, not the brakes.
In the middle of the last century, tuberculosis was considered conquered. Today, it is the world’s second leading infectious disease killer, taking nearly 2 million lives each year. Furthermore, a frightening proportion of new cases of tuberculosis in China, Eastern Europe, India, Russia and South Africa are resistant to current first-line drugs. With air travel, cross-cultural exchanges and immigration, patterns of resistance are steadily making inroads in the United States as well. HIV has fueled tuberculosis across Africa, Asia and Eastern Europe, while the drugs and diagnostics have become increasingly outdated. The disease, in short, has evolved faster than the tools developed in the last century to fight it. Now, it is estimated that more than 1,000 people infected with HIV die every day from tuberculosis, a curable disease.
While the development of Sirturo offers promise of less-prolonged and less-harmful treatment regimens for people with highly drug-resistant forms of tuberculosis, new companion drugs are also needed to prevent even further drug resistance from occurring. It is hoped that these new drugs can be used in place of existing slow-acting and toxic treatments for the most common forms of tuberculosis and be safe in children, pregnant women and other adults, to prevent ongoing suffering, mortality and transmission across the globe.
In addition to the need for new drugs to treat tuberculosis, we need new tools to diagnose and to prevent the disease. The tuberculosis diagnostic test commonly used around the world, which is more than a century old, involves looking through a microscope at a specimen gathered from a patient coughing into a cup. This method catches only about half of all tuberculosis cases and is poorly effective in detecting tuberculosis in people with HIV or children. The good news is that there is a promising new test available, called GeneXpert MTB/RIF. U.S. government funding through the [U.S. National Institutes of Health] NIH helped develop and test the new diagnostic, and [U.S. Agency for International Development] USAID and [U.S. Centers for Disease Control and Prevention] CDC funding is helping hardest-hit countries scale up use of this new breakthrough test. But, without steady investments, these efforts will falter.
Ultimately, a vaccine that is effective against all types of tuberculosis in adults as well as children is the key to permanently winning the battle against the spread of tuberculosis. A recent trial for a vaccine candidate continues.
The science and global support required to conquer tuberculosis has gained momentum over the past 3 decades but will stall without continued, robust U.S. leadership, including commitment to funding to get the job done. We already know that the progression of tuberculosis — to more drug-resistant, even incurable, strains — will not stand still while science pauses. Tuberculosis bacteria know well the concept of “sequestration”; they are masterful at sequestering in the body awaiting a vulnerable moment to cause disease. Without intervention, budget sequestration will serve to put the brakes on our progress, just at a time of great promise. World TB Day prompts us to respect the seriousness of a disease with such longevity and remember that we can pay now or expect to pay for a much longer time, with a more formidable foe.