Global Experts Call for Early Drug Discovery Against MDR-TB

by VR Sreeraman on Nov 6 2007 6:37 PM

The looming threat of an untreatable strain of tuberculosis emerging as the disease becomes ever more drug resistant will occupy the minds of some 3,000 experts at a conference in Cape Town this week.

Though curable, more than 1.5 million people die of tuberculosis every year and growing numbers of patients do not react to standard drugs, the International Union Against Tuberculosis and Lung Disease said in a statement ahead of its 38th world conference on lung health starting Thursday.

"Despite international efforts, the increasing incidence of multi-drug resistant tuberculosis (MDR-TB) and extremely drug-resistant tuberculosis (XDR-TB) threatens to push that number higher," it said.

The five-day conference, which will draw delegates from more than 100 countries, is being held as 37 countries world-wide have recorded cases of XDR-TB -- a near incurable form of the disease.

"There is an urgent need for a TB vaccine and new drugs and diagnostic tools," said the organisers.

No new TB drugs have been developed in more than 40 years and existing methods of testing are too slow to combat the extreme form of the disease as the link between HIV and TB claims an ever-increasing number of lives.

Harvard TB researcher Carole Mitnick told a press conference in Johannesburg last week that an estimated 500,000 new MDR-TB cases were reported globally every year.

"So why hasn't anything been done? The perception has been that the treatment for MDR-TB is too hard and too toxic, therefore the alternative in resource-poor settings has been to just isolate people, hope that they don't transmit to anyone else, and let them die."

Dr Eric Goemaere, head of the Doctors Without Borders mission in Khayelitsha, Cape Town, explained that patients with MDR-TB failed to react positively to drugs that are usually prescribed in the initial stages of the disease.

"When they develop resistance to ... four drugs they become XDR which basically means there is hardly anything left to treat them (with)."

Resistance to TB drugs could develop when patients failed to take their medication as prescribed, or through direct transmission from person to person.

Tuberculosis was the leading cause of death among about 24.7 million HIV-positive people living in sub-Saharan Africa, said the union.

"TB is curable and HIV is manageable with appropriate treatment, but without either, patients will die."

A third of the world's 40-million people with HIV/AIDS are also believed to have TB.

Ahead of the conference, a United States-based medical technology company announced Monday it would slash the price of a tuberculosis diagnostic tool for poor countries with high TB burdens.

Developing nations would be able to purchase the BD BACTECTM MGITTM 960 system at around three dollars per test -- a fifth of the price paid by the United States and Europe, BD vice-president Krista Thompson told AFP.

Thirty-nine countries would benefit from the cut price for technology the company claimed was more accurate and quicker at diagnosing TB and its drug resistant strains.