Why drug manufacturers don’t work on TB drugs

WHO-commissioned study pinpoints 4 barriers

It may not be on the agenda, but you can be sure that one study that will loom large at next month’s TB drug development conference will be an analysis of the pharmaceutical industry’s reluctance to work on new TB drugs. (See related story, below right.)

The analysis was performed by Diana Chang Blanc, a technical officer in the vaccines and biologicals division of the World Health Organi zation. Paul Nunn, former chief of research at WHO’s now-defunct Global TB Programme’s TB Research Unit, had asked Blanc to survey drug companies, ask them whether they had any work under way in new TB drug development, and — if the answer was "no" — find out why not.

In the end, Blanc says she talked to 36 representatives from 19 companies. Of those 19, only five had any TB work under way, two of which have since abandoned their work. Still in the running are Merck Pharmaceuticals, with a single collaboration with an academic partner; Hoechst-Marion-Roussel Pharmaceuticals, which continues to work on rifapentine, an old drug recently approved for use against TB; and Glaxo Wel l come, which funds a series of modest public- private research-oriented partnerships.

Chang says she found there were four main reasons drug companies say they don’t want to work on TB. One is the oft-cited cost — $500 million per drug — of bringing a new product to market. "A drug company’s responsibility is to its shareholders, and if the market analysis for a new drug shows less than $200 million a year in sales, they won’t touch it," says Blanc.

Another related perceived barrier is insufficient market size, she says. "Only 5% of TB cases are in the industrialized world. The remaining 95% are perceived as being unable to pay."

Fear they’d have to give drugs away for free

Industry spokesmen also told Blanc they feared that if they invented new anti-TB drugs, public-sector advocates would force them to sell the drugs at less than cost or simply give them away for free. "They also confessed off the record to fears of having to deal with AIDS activists, since AIDS and TB are synergistic diseases," says Blanc. "And that’s something they said they strongly dislike doing."

In addition, drug companies told Blanc they were confused about DOTS, the WHO’s programmatic strategy for improving patient access to and compliance with existing drug regimens; after all, industry reps asked Blanc, because DOTS is touted by WHO as "a cure for TB," why should industry scramble to invent another "cure"?

"Clearly, we in the public sector have to be careful about how we frame messages about DOTS," says Blanc. "We also have done a lot of shouting about people dying, and a lot of finger-pointing. The truth is we need a new paradigm because what we’ve been doing doesn’t work."