TWN Info Service on Health Issues (March 07/04)

26 March 2007

Drug-resistant TB treatment barely succeeds

Even as WHO released a report which said that the global TB epidemic had levelled off since 1993, Medecins Sans Frontieres released statistics showing that even under optimised conditions, treatment will succeed in barely half of patients with multi-drug resistant TB. Some patients go on to develop extensively drug resistant TB. The article below reports on both views.

It is reproduced with permission from South-North Development Monitor (SUNS) #6217, 23 March 2007.

With best wishes
Evelyne Hong

Health: Treating drug-resistant TB, a losing battle?

By Kanaga Raja, Geneva, 22 March 2007

Multi-drug resistant and extensively drug-resistant tuberculosis are the tip of an iceberg of failing strategies to curb tuberculosis, and the World Health Organization needs to take the lead in developing new strategies against the disease, the international medical humanitarian organization Medecins Sans Frontieres (MSF) warned Thursday.

This grim warning from MSF comes even as the World Health Organization released a report on Thursday in which it maintained that the global tuberculosis (TB) epidemic had leveled off for the first time since the WHO declared the disease a public health emergency in 1993.

The Global Tuberculosis Control Report 2007 of the WHO said that the percentage of the world's population struck by TB peaked in 2004 and then held steady in 2005.

The WHO however acknowledged that the spread of extensively drug-resistant TB (XDR-TB) poses a serious threat to progress and could reverse recent gains.

"We have a clear plan on how to control XDR-TB, but countries are moving far too slowly on implementing this plan. Funding is an issue as well - it will take an additional $650 million globally to implement control of both XDR-TB and multi-drug-resistant TB (MDR-TB) in 2007 alone," said Dr Mario Raviglione, Director of the WHO Stop TB Department.

"Beyond that, because of the threat of XDR-TB, research to identify new diagnostics, drugs and vaccines is more vital than ever," the WHO official added.

MSF released statistics on Thursday showing that even under optimised conditions, treatment will succeed in barely more than half of patients with multi-drug resistant tuberculosis (MDR-TB).

As insufficient research and development on new drugs and diagnostics has left health staff without the right tools to treat the disease, some patients will go on to develop extensively drug-resistant tuberculosis (XDR-TB) regardless of the quality of care they are offered. The situation is particularly alarming when treating people co-infected with TB and HIV, said MSF.

"When resistance emerges to the major TB drugs, we're forced to go back to using older less effective ones," said Dr. Jessica Adam, a doctor in MSF's programme in Uzbekistan. "This means a much longer, much more expensive treatment course that can cost up to $15,000, and especially relying on drugs that are toxic: the side effects are simply horrible."

MSF said that since 1999, it has invested considerable resources, and provided rigorous support to treat 570 patients with MDR-TB in Armenia, Abkhazia, Georgia, Cambodia, Kenya, Thailand, Uganda, and Uzbekistan.

Despite these efforts, only 55% of these patients completed the 18-24 month course of treatment. The remaining 45% died, did not improve on treatment, or defaulted because of side effects, isolation, and other difficulties in tolerating the treatment.

Diagnosing MDR-TB is also extremely difficult, said MSF. Most resource-poor settings do not have access to the necessary sophisticated equipment. But even in the best of settings that do, it can take up to eight weeks to get a result. In patients co-infected with HIV who are already sick, such delays can mean the difference between life and death.

"In places where we see a lot of HIV/AIDS, the risk of MDR-TB spreading like wildfire is a terrifying, but all too likely prospect," said Dr. Liesbet Ohler from MSF's programme in Mathare, a slum near Nairobi.

"Treating MDR-TB and HIV simultaneously is incredibly frustrating because of drug interactions and the potential for many strong side effects, let alone the number of pills patients have to take everyday. With the tools we have today, we're fighting a losing battle."

Last year's XDR epidemic in South Africa sparked international concern about the extent of the crisis and the urgency of finding solutions, MSF said, stressing that concrete actions need to be taken now. The WHO needs to take the lead to develop new strategies against the disease.

Despite the urgency of the situation, MSF said that current research efforts are not keeping pace with the need for better tests, drugs and vaccines. An analysis conducted by MSF of the TB research and development pipeline found that none of the compounds under development today will be able to deliver the drastically shorter treatment that is needed to curb the disease.

Similarly, the diagnostics under development will not be simple enough to use in resource-limited settings and will not reliably detect the disease. There is a critical funding gap for research and development for TB with around $900 million needed annually but only $206 million being invested, said MSF.

"MDR-TB, and now XDR-TB are the tip of an iceberg of failing strategies to curb TB. We desperately need new tools and we need them now - we cannot just sit and wait," said Dr. Tido von Schoen-Angerer, Director of MSF's Campaign for Access to Essential Medicines.

"There is no quick ready-made solution, but that is not an excuse not to act. One important step is to have all TB drugs in development tested in trials with MDR patients: this would be a quicker way to see whether new compounds are efficacious for patients with regular TB and give those with MDR a chance for a better treatment. At the moment, only one company has stated that it is planning to conduct an MDR trial while others sit on the fence. WHO needs to ensure that these trials will happen," he added.

Meanwhile, according to the WHO Global Tuberculosis Control Report, the global tuberculosis epidemic is leveling off, with the percentage of the world's population struck by TB peaking in 2004 and holding steady in 2005.

The WHO said that although the rate at which people developed TB in 2005 was level or even declined slightly compared to 2004, the actual number of TB cases continued to rise slowly. The reason for this difference is that world population is expanding.

The pace at which new TB cases developed in 2005, however, was slightly lower than global population growth. The number of cases in 2005 was 8,787,000, up from 8,718 000 in 2004. An estimated 1.6 million people died of the disease in 2005, 195,000 of them people living with HIV.

The WHO said that more than 90 million TB patients were reported to the organization between 1980 and 2005.

The WHO report noted that facilities to diagnose and treat MDR-TB, including XDR-TB are not widely available yet, and that the scale of the XDR-TB problem globally is not yet known.

The WHO also highlighted an overall funding gap for TB control. Although funds for TB control have risen substantially since 2002, reaching $2 billion, an additional $1.1 billion will be needed to meet the 2007 funding requirements set by the Global Plan to Stop TB (2006-2015). A total of $56 billion - half of which should be funded by endemic countries and the other half by donors - is needed for the 10-year plan, but current funding commitments indicate a gap of at least $31 billion.

The WHO report also found that the WHO Regions of the Americas, South-East Asia and the Western Pacific are now on track to meet their 2015 Global Plan Targets (to halve 1990 TB case numbers and deaths from the disease by 2015); while the African, Eastern Mediterranean and European regions are not.

The WHO said that its 2005 targets of 70% case detection and 85% cure were narrowly missed globally: case detection was 60% and treatment success was 84%.