Updated on 4 May 2012
What do you think are the major obstacles that are hindering the complete eradication of TB from the world?
TB is a disease where there is huge medical need and not enough research activities. TB is an old disease that has been with mankind for quite some time and there have been few very good drugs. These drugs are about 40 years old and usaghe of the drugs for such a long time has led to increase in the number of resistances and thus these drugs do not work anymore. There is a family of TB, which is recent, called TDR, that is Total Drug Resistance where nothing works. And we are seeing an increased number of patients showing this type of resistance. TDR was not much apparent nine years ago but now it has exploded all over the world.
Moreover, you have to work for six to eight months with a combination of drugs to treat TB and as you can imagine this is extremely difficult to sustain in countries like India or Africa. It is very difficult to have people to take the drug everyday at the right time, in the right combination for nine months. Especially since these drugs work quite well, the patients feel no symptoms after two months and they stop taking the drugs. What happens during this time is that you kill the selective bacteria and you have kept the more resistant ones. This leads to resistance.
Another thing that makes everything very slow in TB is that the bacteria grow very slowly and it takes week to do an experiment. And this problem is faced even in the in-vivo testing cos when u see that these drugs will kill the bacteria in a dish u need to verify that in an animal model and that takes even more time. So the turn around time is several weeks and this has nothing to do with modern science. Modern scince cannot make the bacteria grow faster. So that remains the bottleneck. That is why after one year we are only in the very early part of the pipeline.
What are your most important concerns that continue to be associated with the treatment of TB?
Clearly, the concern with new drugs is how to control them such that they will never be used in an inappropriate manner. For example, if a new drug or a new antibiotic is used alone and is not used in combination with another drug, then there is a high probablity that within a year or so there will be resistance from the microbe. It takes 15 years to make a new drug and we lose it in one year due to inappropriate usage. Once you have developed a drug, you should use it in a way such that you will not loose it immediately. Another concern is the cost of drug development in TB. Developing a drug for the poor people is not cheaper than developing a drug for the rich people. The science and the technology involved is the same.
How are these concerns being addressed?
The World Health Organization (WHO) is addressing the drug control problem. It is trying to tell the people that if you continue to use TB drugs inappropriately, you will be unable to control the problem.
What do you think is the future of Tuberculosis drug development?
The future is to use the techniques that have never been used for TB before. So the breakthrough really is to explore new chemistries, to adress the disease and to kill the bacteria with weapons that have never been seen before. The real breakthrough will now come by applying all our knowledge to find new chemical classes and bring them into this field of research.