Why do you think development of new antibiotics is not very attractive venture for the pharmaceutical companies?

Answer 1

Development of new antibiotics no longer attractive for pharma industry

Bacteria become pathogenic under varied circumstances especially when the host defenses become weak due to whatever reasons e.g. poor nutrition. Louis Pasteur, Joseph Lister and others began linking these bacteria to disease and today the discipline of infectious disease has become the greatest ever challenge facing the scientific world. Discovery of Penicillin by Sir Alexander Flemming - its impact and value - was realized as a great breakthrough in the world of life sciences during and after World War II. Advances in medical technology increased our success in combating the bacterial diseases with the manufacture of a variety of antibiotics - tetracycline, streptomycin, ampicillin, amoxicillin etc. and so on - indeed once labelled as the wonder drugs. But today these wonder drugs and their development is no longer an attractive venture for the pharmaceutical companies - why?

Due to ever changing environment - external and/or internal - these bacteria evolved their own mechanism of defense that helps them survive the adversaries of the environment. One theory that shook the entire scientific world and stood the test of the time is the so called 'Theory of natural selection' by Charles Darwin with the core concept that struggle for existence leads to origin of new species and strains. Such species and strains become well equipped to handle the disturbances in their environment including the milieu interior of the human body. During their struggle for existence, these organisms - prokaryotes as well as eukaryotes acquire ever emerging newer mechanisms of resistance that help them overcome the adversaries in environmental conditions by evolving through the process of adaptation - a process of acquiring or developing newer characters which help them survive the adverse environment conditions, and, indeed this 'survival of the fittest', then, leading to emergence of newer species and strains.

By analogy, whenever an antibiotic is administered to eradicate the disease producing pathogenic bacteria, it tends to eliminate not only the pathogenic bacteria but also in the process inflicts damage to the non-pathogenic bacteria, especially 'commensals' that leads to serious disturbances in the milieu interior. At this stage comes struggle for existence for these microbes. Every living being on the planet earth, be it a microbe or human being is, hitherto, provided with defense mechanisms exclusive to the 'one life' itself. This defense arsenal, in microbes exists in the form of resistance mechanisms that lead to microevolution at a fairly rapid rate. Of these, the R-plasmids are the most significant. Exposure of a bacterial population to a specific antibiotic, in the laboratory designed system or within a living system, kills the antibiotic sensitive bacteria but not those that possess R-plasmids or resistance mechanisms. Theory of natural selection predicts that under these circumstances an increasing number of bacteria inherit genes for the antibiotic resistance (microevolution). This resistance, in turn, must spread for the benefit and survival of the entire affected bacterial population to maintain its population dynamics and equilibrium in the given ecosystem.

To this spread of resistance far and wide across the globe at a very rapid rate, contribute the unique mechanisms of reproduction (which these tiny microbial microscopic lives are naturally endowed with) - such as transformation, transduction and conjugation processes. So, the new species or the strains are now well adapted 'survival of the fittest' and spreads rapidly to restore its own population equilibrium in the vast ecosystem - an ecosystem for these inhabitants of earth that recognize no man made regional demarcations or boundaries. What is the net result?

The antibiotic that triggered all these events now becomes less and less effective, virtually ineffective, undergoing its natural elimination from the market usage culminating into huge economic losses for the pharmaceutical industry, a loss that could run into billions of dollars. The cow gives no more milk - it is dry and dumping this cow (the ineffective antibiotic) needs more investment than the money spent on its manufacture. The problem gets further compounded by the fact that there exist no universally acceptable guidelines to affect the judicious use of antibiotics. The net result is indiscriminate use of these wonder drug - the plethora of antibiotics manufactured all across the globe with the hope that one day at least, it will help, if not eliminate but contain the spread of eradicable bacterial diseases.