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TB Immune to Drugs Proves Hard to Detect




 

Drug-resistant tuberculosis is going largely undetected in many countries, threatening progress made against the pernicious lung disease over the past decade, according to data in a World Health Organization report released Wednesday.

The number of people becoming ill with tuberculosis has been falling steadily for roughly a decade after a surge in the 1990s, with a 2.2% drop globally in 2011. About 8.7 million got sick and 1.4 million died in 2011, including 430,000 people who were infected with HIV, the virus that causes AIDS and makes individuals more susceptible to tuberculosis infection.

But those numbers are still huge, and only 19% of those infected with forms of the disease that are resistant to multiple tuberculosis drugs are being diagnosed, the WHO estimated. The agency cited a lack of funding and technology for appropriate diagnostic testing in countries where drug resistance is flourishing.

Because patients in many countries aren't tested fully for so-called multidrug-resistant tuberculosis, it is difficult to know how widespread that form of the disease is or whether the number of cases is rising, said Mario Raviglione, director of the WHO's Stop TB Department.

Fewer than 60,000 new cases of "MDR-TB" infection were reported in 2011, mostly by countries in Europe and Africa. That is only 19% of an estimated 310,000 people who were diagnosed with tuberculosis last year but actually had a drug-resistant form. There are about 650,000 cases of MDR-TB globally.

An estimated 6% of patients with MDR-TB in India and an estimated 3% of patients with MDR-TB in China were diagnosed, the WHO said. India, China, Russia and South Africa account for nearly two-thirds of drug-resistant cases, Dr. Raviglione said.

"India and China particularly need to accelerate detection, diagnosis and treatment of MDR-TB," he said. Moreover, "if these four countries don't move, we will always have slow progress."

Drug resistance is also deepening, with 84 countries now reporting cases of extensively drug-resistant tuberculosis - a form that is resistant to at least four core tuberculosis drugs. Cases of an even more resistant form of tuberculosis that defies all traditional treatment have been reported in India.

Such trends pose a grave challenge for global health officials as they try to contain one of the world's largest infectious-disease killers. Health officials said Wednesday that while they now have to rely on medicines developed half a century ago to battle the disease, the pipeline is finally filling with promising new diagnostic equipment and drugs.

But the WHO projected that funding would fall about $3 billion a year short of the $8 billion it says is needed annually from 2013 through 2015 to fight tuberculosis in developing countries.

"We are really now at a crossroads with tuberculosis; we finally have the technology and this is the time to push, but we're concerned about the financing gap," Dr. Raviglione said.

The new technologies include a rapid molecular test that can diagnose tuberculosis and a common form of resistance in 100 minutes - the first major advance in tuberculosis diagnostics in more than a century. The WHO said about 1.1 million of the Xpert MTB/RIF tests have been put to use in 67 countries. A group of donors including the U.S. government and the Bill & Melinda Gates Foundation in August struck a financing agreement with the manufacturer, Cepheid, CPHD -7.54% to help make the test more accessible by dropping the price of test cartridges in developing countries.

Tuberculosis drugs currently in use are about 50 years old, and standard treatment takes about six months, while treatment for drug-resistant forms takes around 20 months. The WHO said 11 new or repurposed tuberculosis drugs are in clinical trials that offer a new line of attack against drug resistance and could shorten treatment times. Among two drug candidates that are in late-stage trials and could be used to treat MDR-TB patients because they are entirely new compounds are Otsuka Pharmaceutical Co.'s delamanid and a drug known as TMC207, which is being developed by a subsidiary of Johnson and Johnson JNJ -0.79% . There are also 11 vaccine candidates in trials.

The "holy grail" of drug development is a drug regimen to which there is no resistance, said Mel Spigelman, president and chief executive of the TB Alliance, a nonprofit group that pushes for development of tuberculosis drugs. Another goal is testing regimens that allow doctors to determine exactly what drugs a strain of tuberculosis is resistant to, and then to match that diagnosis to treatment with specific drugs.

Dr. Raviglione said the WHO has formed a task force to sort out how to use the new drugs without fostering more drug resistance. "The risk is that they're misused, and the end result would be the development of resistance within months," he said.

Write to Betsy McKay at betsy.mckay@wsj.com



 


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Information in this article was accurate in October 18, 2012. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.