Alice Tembe, CNS Special Correspondent, Swaziland
(CNS): In the light of the outcry of the high pill burden, severe toxicity and high treatment non-adherence rates, and many more challenges associated with the treatment of TB, in particular of multidrug-resistant tuberculosis (MDR-TB), innovative drug therapies are beginning to be explored. One of them - inhaled TB drugs - were presented at the 46th Union World Conference on Lung Health held recently in Cape Town.
Professor Anthony Hickey, a Senior Research Pharmacologist at RTI International Research Triangle Park, was of the opinion that inhaled drug therapy for TB should not be approached with any fear and the duration to get it to commercial production should not be too long, considering that it is not, and will not, be an entirely new and blind search for effective options.
There is a history of inhalation therapy in the late 1940s when the streptomycin drug started showing signs of resistance. The inhalation therapy was however abandoned only to resurface in the 1980s in trials for HIV drugs until 2010 when tobramyanin was rolled out. But then, after this, it seems the trail died again,even though there were indications of effective responses. Needless to say, there is already a model to follow for researchers, as outlined by this history on inhaled therapies, from the stages of formulation of the drug, dosage development, device development for administration, and the steps towards product approval. These were the sentiments shared by Professor Anthony Hickey.
It has been noted already that oral or injectable drug therapy are probably the cheaper way to administer TB drugs. However, it is also evident that these approaches have not been the most favorite among patients and even health care professionals. Inhalation therapies may actually be more expensive to take to the ordinary person but as shared by Dr Stefano Giovagnoli, Assistant Professor in Pharmaceutical Sciences at the University of Perugia, Italy, there are great health benefits that the inhaled therapy brings.
Firstly, for lung delivery there can be cellular targeting in high concentration of TB bacilli. This may possibly rapidly reduce transmission of the TB bacilli due to high airway concentration of drug delivery. Secondly, there will be lower systemic exposure, thus minimizing side effects, especially like damage to the liver, since the drugs will be administered directly to the lungs. Thirdly, inhaled dosages can be easily manipulated to be lower or higher as needed. This means that dosage can be easily adjusted in case of children and adults, as well as for prophylactic doses. Lastly, there can be systemic onset of action, thereby accelerating high surface area for absorption.
The advantages of inhaled drug therapy could be endless. It would accentuate other health benefits and long term research and management of TB. Unlike injections, inhalers are non-invasive and also eliminate needle based risks of cross infection, especially for patients with HIV and hepatitis; and eliminate the pain associated with injectables for MDR-TB treatment, especially in underweight adults and children.
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