Monday, March 24, 2008 marks World TB Day, which commemorates the date in 1882 when Robert Koch discovered Mycobacterium tuberculosis, the cause of tuberculosis (TB). World TB Day provides an opportunity to raise awareness of the disease and for TB-prevention organizations to support worldwide TB-control efforts. The
Christine F. Sizemore, PhD, Barbara E. Laughon, PhD, and Anthony S. Fauci, MD, experts from the National Institute of Allergy and Infectious Diseases and the National Institutes of Health, issued the following statement:
As we commemorate World TB Day, we recognize the important strides made in combating tuberculosis (TB) over the past several years, and, simultaneously, are reminded of the substantial challenges that lie ahead. Nearly one-third of the world's population is infected with Mycobacterium tuberculosis (Mtb), the bacterium that causes TB, and more than 14 million people are afflicted with TB disease, with high-burden countries showing a continued increase in the number of patients diagnosed. In 2006, an estimated 9.2 million new cases of TB emerged, of which approximately 700,000 occurred among individuals also infected with HIV. The same year, an estimated 1.7 million people died of TB, including 200,000 patients co-infected with HIV.
Recently, the World Health Organization (WHO) reported that the incidence of multidrug-resistant TB cases is on the rise. Among new cases of TB, an estimated 5 percent, or 500,000 annually, are multidrug resistant (MDR), with resistance to at least the first-line TB drugs isoniazid and rifampin. An estimated 10 percent of all MDR TB cases are extensively drug resistant (XDR); they do not respond to therapy with the most effective anti-TB drugs. The spread of drug-resistant Mtb strains to HIV-infected people poses significant challenges in countries with high rates of TB and HIV infection and threatens to reverse gains made in the control of these diseases.
Controlling the spread of TB and slowing the development of drug-resistant Mtb strains requires an integrative approach. NIAID works with domestic and international partners to support basic, translational and clinical research that helps us better understand TB and develop new diagnostics, treatments and prevention tools. In 2007, the Institute released the NIAID Research Agenda: Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis, which identifies research priorities in TB-related areas. The agenda also highlights the importance of fostering partnerships with public and private organizations to fuel the pipeline of available drugs, diagnostics, and preventive measures for TB.
Domestically, NIAID coordinates its work on TB with other NIH Institutes and Centers, the U.S. Centers for Disease Control and Prevention (CDC), the U.S. Agency for International Development (USAID) and other federal agencies. These interactions are facilitated through the Federal TB Task Force and the NIAID-CDC Joint Partnership Implementing TB Elimination Research. In addition, NIAID coordinates efforts with for-profit and not-for-profit agencies, as well as public-private partnerships. Internationally, through the Stop TB Partnership, NIAID collaborates closely with organizations that conduct and monitor disease and drug resistance surveillance, provide clinical care for TB patients (with and without concomitant HIV infection), and support research training and TB control programs throughout the world. Such partnerships must be strengthened and new opportunities pursued as we work to bolster efforts to control TB and halt the spread of drug-resistant Mtb.
Because of the profound effect of HIV co-infection on the course of TB and vice versa, we must better integrate the diagnosis, care and treatment of people who have HIV/AIDS, TB and other diseases. We are working to develop improved diagnostics that would allow HIV-infected people to be rapidly tested for Mtb and for TB patients to be tested for HIV infection so that appropriate treatment can be initiated as soon as possible. We also are working to better understand which TB drugs work most safely and effectively in HIV-infected individuals, particularly those receiving antiretroviral therapy. In addition, we are developing new, faster-acting anti-TB therapies.
Ultimately, controlling TB depends on effective prevention strategies, especially vaccines, and TB vaccine development is a critical goal of the NIAID research agenda. An ideal vaccine would be safe and efficacious for everyone, including those infected with HIV.
As partnerships for creating new drugs, vaccines and diagnostics are established, we continue to work with our partners to better understand the needs of TB-endemic countries and to assure that diagnostic, therapeutic and preventative tools that have been developed in wealthy countries are affordable and practical in resource-limited settings. We are working to improve communication among basic research scientists, manufacturers and clinical care providers so that the development of efficacious and appropriate intervention tools and strategies is guaranteed from the earliest stages of research.
Many important TB research programs are bearing fruit. For example, researchers from the United States and South Africa recently determined that little variation exists between the genomes of MDR- and XDR-TB strains. This study and others like it contribute to an understanding of factors contributing to drug resistance and provide new leads for diagnosing and treating drug-resistant forms of TB. SQ109, an anti-TB drug candidate developed through a partnership between NIAID and Sequella, Inc. was recently granted orphan drug status by the U.S. Food and Drug Administration and the European Medicines Agency for potential use against drug-susceptible and drug-resistant TB. NIAID has assisted in the preclinical development of another candidate drug, PA-824, currently in Phase II clinical trials sponsored by the nonprofit Global Alliance for TB Drug Development. In addition, NIAID recently formed a partnership with the Eli Lilly Foundation, the Infectious Disease Research Institute of Seattle, and others to further stimulate TB drug discovery. This effort is called the Lilly Not-for-Profit Partnership for TB Early Phase Drug Discovery.
Although significant progress has been made, much remains to be done. NIAID is working to better integrate individual resources to create efficient pathways that will rapidly lead to candidate drugs, diagnostics and vaccines. The most promising of these will be assessed in clinical trials of the highest quality.
Combating TB requires cooperation by scientists, manufacturers, funders, policy-makers, advocates, and, ultimately, healthcare providers and patients to work together on new approaches to this devastating disease. As we commemorate World TB Day this year, we commend the efforts of scientists, clinicians and volunteers who work tirelessly to contain the spread of TB and to improve the health of TB patients throughout the world, and hope that more individuals will join this most important global health endeavor."