What We Do

Tuberculosis

Strategy Overview

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Better vaccines, drugs, and diagnostics are needed to reduce the burden of TB, which remains one of the leading causes of death worldwide.

our goal:

to accelerate the decline in tuberculosis incidence worldwide.

The Challenge
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At A Glance

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The global TB mortality rate fell by 45 percent between 1990 and 2012, but TB remains one of the leading causes of death worldwide, with almost 9 million new cases reported each year.

The TB vaccine used today provides limited protection for newborns and children and no protection against pulmonary TB in adults, which accounts for most of the TB cases worldwide.

The foundation is working to better understand the basic science behind the TB epidemic to help improve the approaches to developing and deploying better vaccines, treatment regimens, and diagnostic tools.

Our TB strategy is led by Gilla Kaplan, director, and is part of the foundation’s Global Health Division.

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Over the past two decades, significant progress has been made in the fight against tuberculosis (TB). Between 1990 and 2012, TB mortality worldwide fell by 45 percent. Due to coordinated global efforts and the use of the directly observed therapy short-course (DOTS) strategy, the recommended treatment for TB developed in the 1980s, 56 million people with TB were successfully treated between 1995 and 2012, saving 22 million lives. An estimated 1.3 million lives were saved through increases in collaborative treatment of TB and HIV between 2005 and 2011.

Despite this progress, TB remains one of the leading causes of death worldwide. In 2012, an estimated 8.6 million new cases were reported and 1.3 million people died from the disease. In recent years, TB control efforts have taken on increased urgency due to the emergence of multidrug-resistant TB (MDR-TB), a form of the disease that is resistant to frontline drugs, and extensively drug-resistant TB (XDR-TB), which is also resistant to some second-line drugs. MDR-TB has emerged in nearly every country in the world, with an estimated 450,000 new cases in 2012. These forms of the disease are especially difficult and costly to treat and are a consequence of years of inadequate diagnosis and treatment. The TB epidemic in countries with a high rate of HIV has also accelerated. In 2012, about 320,000 people died who were co-infected with TB and HIV.

Current approaches to preventing, diagnosing, and treating TB are inadequate. The TB vaccine used today provides limited protection for newborns and children and no protection against pulmonary TB in adults, which accounts for most of the TB cases worldwide. The most commonly used diagnostic tool, the microscope, detects only half of all cases and is labor-intensive for health providers and requires special skills. Finally, while the standardized DOTS treatment regimen has had significant success, it requires the patient to take a complex combination of pills every day for six to nine months, assumes that a healthcare worker will supervise the full duration of treatment, and has significant side effects. The result is that many patients end treatment prematurely.

The Opportunity
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The past decade has seen substantial new investments in addressing the TB epidemic, and a number of new tools are in development. New drugs, diagnostic technologies, and eventually a vaccine could vastly improve the worldwide response to TB. But more research and development is needed to ensure that these tools are as effective as possible and are affordable and simple to use. A more effective vaccine would be the single most powerful tool to reduce the incidence of TB. Even a partially effective new vaccine could, by some projections, decrease TB incidence by 39 to 52 percent by 2050.

However, the first candidate vaccine developed and tested in Phase III trials failed to protect infants against the disease, and finding a new, efficacious vaccine could take many years. It is therefore critical to also develop short- and medium-term strategies that can help reduce the rate of TB infection. For example, new TB diagnostic tools can reduce treatment delays and make it more likely that the disease will be caught before the patient transmits TB to many others. In addition, a simpler, shorter-course drug regimen would improve treatment success rates because patients would be more likely to complete it.

The drugs and diagnostic technologies that are currently in clinical development can reach those who need them most only if they are affordable and can be deployed efficiently. Substantial financial resources for research and development are needed, and investments from developed and TB-endemic countries, pharmaceutical companies, and foundations must be sustained.

Our Strategy
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The Bill & Melinda Gates Foundation’s TB strategy addresses many of the factors associated with the TB epidemic.

A new vaccine would provide the most effective way to decrease the incidence of TB, so our top priority is to explore innovative and accelerated approaches to vaccine development. However, the combined deployment of vaccines, diagnostics, and drugs is essential to addressing the epidemic.

We are also focusing on the development of shorter, simpler treatment regimens. Patients who do not complete their treatment as prescribed are likely to continue to transmit TB to others and may develop drug-resistant strains that can take up to two years to treat with more expensive, second-line drugs.

Another area of focus is the development of faster and more accurate diagnostic tools, which would lead to earlier treatment and fewer transmissions of the disease. But tools that can be used to detect TB more efficiently as well as diagnose drug-resistant TB, such as the GeneXpert device, can improve treatment outcomes and save millions of lives only if they are implemented rapidly and effectively where they are most needed. We are therefore funding operations research in India, China, and South Africa, which together have nearly 40 percent of the world’s TB cases; South Africa alone has one-fifth of all African TB cases and significant numbers of people with HIV and TB co-infection.

We also advocate for adequate financing to combat TB. We support efforts to raise critically needed funding for research and development. And we work with global financing institutions such as the Global Fund to Fight AIDS, Tuberculosis and Malaria and UNITAID to reduce the cost of innovative technologies and accelerate their adoption.

Areas of Focus
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More Effective Drug Regimens

TB can rapidly develop resistance to a single drug, so treatment will always require a combination of drugs. However, conventional drug development requires that new TB drugs be evaluated separately in clinical trials, so new drugs can be tested in combination only after they have been approved individually. This means that developing more effective TB regimens could take decades. To address this obstacle, we have joined with partners to create the Critical Path to TB Drug Regimens (CPTR) initiative, which brings together leading international pharmaceutical companies, public health experts, nongovernmental organizations, and U.S. and other regulatory authorities to expedite testing of promising TB drug candidates in combination and to identify new regulatory pathways and other means of accelerating the drug development process.

We are currently helping to fund clinical trials of a new TB drug regimen called PaMZ, which could significantly shorten treatment time and dramatically reduce the cost of treatment. Earlier clinical studies of PaMZ have shown its promise in treating MDR-TB as well as forms of TB that respond to existing drugs.

Our efforts to radically shorten the course of treatment also include our TB Drug Accelerator program, which aims to identify new ways to target bacteria that are resistant to current drug regimens, develop new tools for drug discovery, and discover new drugs that can lead to accelerated treatment regimens.

New Diagnostic Tools

The microscopy room at a hospital specializing in tuberculosis and respiratory diseases in New Delhi, India.

Of the estimated 8.6 million new cases of TB worldwide each year, almost 3 million are unreported. We are developing less expensive, more effective diagnostic tools that can reach more of the TB patient population and can be used at the point of care rather than requiring processing by a distant lab. Part of this effort involves research into new biomarkers of TB infection and treatment responses that will improve detection and clinical management of TB.

One new technology we have funded, the GeneXpert device, has led to an increase in overall TB case finding and has the potential to more effectively guide proper treatment. Our investments in the next generation of molecular diagnostics include a new TB diagnostic tool from the device manufacturer Alere that promises to be less expensive, require less training, and detect TB and drug resistance with a single sputum sample.

Improved Vaccines

We are investing in the development and regulatory approval of more effective TB vaccines. However, the mechanisms of vaccine-induced protection against TB are poorly understood, and there are no known biomarkers that can predict the efficacy of a TB vaccine candidate. This means vaccine development currently involves lengthy and costly trials.

To address these challenges, we created the TB Vaccine Accelerator program, which works to identify promising vaccine concepts that are alternatives to those currently in the pipeline and have a high potential of improving our understanding of TB and leading to more effective vaccine development.

Innovative Delivery Approaches

We are conducting pilot studies to modernize TB control in India, China, and South Africa and using the findings to disseminate the most effective approaches globally. One of our projects focuses on finding cost-effective ways to deploy a more rapid and accurate diagnostic tool in South Africa and to ensure that it is linked to appropriate treatment. In India, we have supported efforts to bring together the Indian government, the World Health Organization (WHO), USAID, and the World Bank to support innovative TB control efforts. We are also engaging the private sector in India to promote TB diagnosis and treatment research and development. Through our advocacy work in China, MDR-TB has been classified as a “highly reimbursable disease” under the country’s health insurance schemes, which means that Chinese patients with this condition will be more likely to receive financial assistance in paying for their treatment.

We also collaborate with global health partners such as the Global Fund to Fight AIDS, Tuberculosis and Malaria; WHO; and UNITAID to make the most of their resources and investments and thereby reduce the cost of innovative technologies, attract enough manufacturers to ensure stable and affordable prices for new TB technologies, and accelerate adoption of effective new approaches to fighting TB.

Advocacy

Staff members at the Coptic Mission Hospital in Lusaka, Zambia, which has special programs to treat TB and HIV.

We advocate for greater political commitment and funding for fighting TB, particularly for research and development in the later phases of clinical trials. We believe that strengthening partnerships with donor governments and multinational institutions, the pharmaceutical and biotechnology industries, and governments of TB-endemic countries is critical to fighting the disease. These partnerships can lead to greater investment in research and development as well as in the delivery of existing and new tools.

 

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