A review on recent development of common cold therapeutic agents.

ABSTRACT

(1) The common cold is a frequently occurring illness caused by rhinoviruses. Inspite of its ubiquitous occurrence the disease has defied all efforts of finding a cure. The current approaches to the treatment of common cold can be divided into two important categories the antiviral and antiinflammatory; both of these leave a lot to be desired. Most of the rhinovirus serotypes use a single cellular receptor, i.e. the intercellular Adhesion Molecule-1 (ICAM-1) for attachment to the cells. This has lead to the development of blockers of this receptor in an effort to find a cure for the common cold. (2) Recently tremacarmra, a synthetic ICAM-1 glycoprotein has been investigated in human volunteers as an antiadhesion molecule towards an approach to common cold therapy. Two dosage forms of the compound-phosphate buffered saline spray and carboxymethyl cellulose-mannitol powder spray were administered intra-nasally in two modes--pre-inoculation (7 h prior) and post-inoculation (24 h after) time periods of rhinovirus type 39 challenge to different groups of human volunteers. Both the treatment modes produced a significant decrease in the symptoms score of clinical illness and concentration of interleukin-8 in the nasal lavage. Saline spray was found to be devoid of any side effects, whereas powder spray produced some nasal irritation initially. The encouraging results of clinical trial with tremacamra show that a cure for common cold is not far off. However, it remains to be seen what would be the impact of such synthetic protein administration on the immune response of the body, should such compounds be used repeatedly. Further, since all colds are not due to rhinovirus it would be wise to restrict the use of tremacamra during autumn and spring when rhinoviruses are known to be the causative organisms of common cold.