Extremely Drug-Resistant Tuberculosis Threatens Western Health Care System

Tuberculosis (TB) is one of the most prevalent bacterial infectious diseases worldwide. World Health Organisation (WHO) estimates that every third person in the world is now infected. Mycobacterium tuberculosis, the microorganism causing the infection is transferred through air. TB usually causes lung infection, but can also affect kidney, brain and spine. If untreated, it can lead to death.

Tuberculosis is a global health threat

Twenty years ago, WHO declared the spreading TB infection as global emergency. Significant funds and resources were invested into the management of TB and development of novel drugs but, as it stands now, TB became even more dangerous and widespread.

Multidrug resistance in TB is defined as the lack of response to the treatment by two powerful antibiotics – rifampicin and isoniazid. These antibiotics are used as a first line of treatment. Resistance can develop as a result of using just one drug for the treatment of TB infected patients (monotherapy) and poor adherence to drug regiments. Ones MDR strain emerges, it can be transmitted within the community.  MDR resistant TB has to be treated with the second line therapy which involves more drugs, longer duration of treatment and lower success rate.

Multidrug resistant and extremely drug-resistant forms of tuberculosis

MDR form of TB was very unusual 20 years ago, but now it is reported virtually everywhere. In some regions of Central Asia and Eastern Europe MDR represents a very significant proportion of new TB cases (9 to 32%). But the most alarming recent development is the emergence of new, so-called extremely drug-resistant (XDR) form of TB. This form does not respond to rifampicin, isoniazid, fluoroquinolones and at least one of the injectable second line treatments. Such level of resistance makes this form of TB practically untreatable. 84 countries around the globe have already reported at least one case of XDR TB.

Global efforts and new political vision are needed to tackle the emergence of untreatable tuberculosis

In the modern world, drug discovery and development is a domain of multinational pharmaceutical companies. The business is money driven – successful drug can be extremely profitable and bring billions of dollars to the inventors. Unfortunately, drug development is also a very expensive process. On average, introduction of one new successful drug costs well in excess of US$ 1 billion these days. When starting a new drug development process, pharmaceutical companies must be sure that their huge investments will be at least compensated by the future sales. Unfortunately, this is not the case when disease is more common in poorer countries.

Tuberculosis Problem Is Typical For Neglected And Orphan Diseases

A number of diseases prevalent in the Third World are considered now as so called orphan or neglected diseases. TB might be common worldwide, but with only 98 patients in the US in 2011 it is considered as orphan disease which is unlikely to bring any profits to those who invest money into developing cure for this condition. Many other well-known infections belong to the same category.

Malaria, leprosy, river blindness and sleeping sickness do not have effective treatments. These diseases are more common in sub-Saharan Africa and tropical parts of Asia and Latin America. Most countries in these regions are too poor to afford providing any new expensive patented medicine to their citizens.

There is also a significant number of rare diseases (such as some genetic disorders) which suffer the same problem as infectious diseases of Third World. When the potential market for a new drug is measured by only few thousands of patients, there is no financial incentive to spend hundreds of millions of dollars to the development of this drug.

Threat of multidrug-resistant tuberculosis to the Western health care system

It is obvious that the lack of financial incentive prevents the profit-driven pharmaceutical companies from entering the markets for orphan and neglected diseases. This is the area of significant global concern. Now, when the global movement of people is fast growing, the national borders don’t protect from the spread of infections any longer. Tuberculosis is one of such infections.

Unfortunately, the response of most governments around the world to this threat has been so far complacent and mostly neglectful.

Call for urgent political action

Under these circumstances, new political decisions must be made. And it is very important that these decisions are made as soon as possible. Money for new drug development should be found from non-commercial sources. Drug development takes many years. If it doesn’t start now, there will be no hope for tackling the XDR form of TB once it spreads. TB treatment and management strategy requires good rethinking. Even in many Western countries, the detection of multidrug resistant strains of M. tuberculosis is not done as a matter of routine. These results in prescribing wrong drugs to the patients, leading to unnecessary and avoidable negative effects to the health and further promoting the rise of drug resistant TB strains.

A series of articles dedicated to the growing problem of TB was published in March this year in The Lancet. The articles written by established academics, medical professionals and dignitaries highlight the need for urgent action and outline what needs to be done. They suggest a number of action points that has to be acted upon in the near future. From the professionals’ point of view, situation is still manageable at present time. But if the resources are not found and political decisions are not made, TB is bound to shake the foundation of modern healthcare.

Bright spots in TB drug development

Despite the lack of commercial interest in the development of TB drugs, some work in this area is being performed. In December 2012, U.S. Food and Drug Administration (FDA) has approved a drug called Sirturo. This is the first treatment for TB approved in the last 40 years, which is based on a completely new mechanism of action and targets the MDR form of the disease. Introduction of Sirturo is an important step in improving the management and treatment of TB, but clearly much more needs to be done to improve the general global situation.