Expert shares fears of TB and AIDS resistance

September 17, 2007

The 2006 U.S. incidence rate for tuberculosis is the lowest since the start of national records. But unless we are careful how we give medications out around the world, we could create caldrons of TB drug resistance a plane-ride awa

Iseman has treated and studied TB for 40 years and has been editor of the International Journal of Tuberculosis and Lung Disease. He also has been part of the team treating Andrew Speaker, who made recent headlines by flying overseas after he was suspected of having extensively drug-resistant TB (XDRTB). The researcher spoke at the recent news symposium of the National Foundation of Infectious Diseases, in Washington, D.C.

Patient compliance

Asked about R.Ph.s' possible role in the evolving world of drug resistance, Iseman noted that, with TB, for example, some U.S. jurisdictions require pharmacists to report to a public health authority when they dispense more than a particular level of drugs used for the disease, even though physicians are obligated to report the diagnosis. And in some countries, he said, pharmacists become agents of DOT, with patients coming into the pharmacy several times a week.

Ample proof of the need for such control is already with us in the form of "manmade" drug-resistant TB, which was created by the lack of such strictures, Iseman said. "What is going on in the world now is that there are epidemics of highly drug-resistant TB that are almost like going back 70 years in time. These patients have TB that is resistant to all of the available, practical medications." In some cases, effective drugs are not available at all, and in others they are not available in most parts of the world, he said.

So the patients are destined to fail therapy, Iseman said, and "before they fail therapy, they will probably spread their drug-resistant TB to others." What makes this an incendiary situation, he explained, is the possibility that drug-resistant TB will get mixed with the AIDS population, as happened in this country: "The epidemic exploded and it was lethal."

Linked threats

But TB and AIDS are linked threats not only because they are so deadly in combination, but also because their drug-resistance science and history are analogous, Iseman stressed. "HIV antiretroviral therapy requires three-drug therapies or else the virus will mutate and escape the drugs." That's why, he said, with the "understandable, passionate desire to make antiretroviral therapy available around the world where people are suffering and dying of AIDS, we have to take exquisite care to be sure that the treatment is delivered reliably. Because we could, through unintended consequences, create extensively drug-resistant HIV. I can imagine a situation where, if we have drug-resistant HIV and drug-resistant TB, there is just no chance for people."