A Randomized, Double-Blind, Placebo-Controlled Pilot Clinical Study on ColdZyme® Mouth Spray against Rhinovirus-Induced Common Cold

Abstract

Common colds incur significant costs in terms of sick leave and personal discomfort for affected individuals. This study investigated the performance of ColdZyme® Mouth Spray (ColdZyme), a protective barrier against common cold, in rhinovirus-inoculated healthy volunteers. This randomized, doubleblind, placebo-controlled pilot study was conducted on 46 healthy volunteers inoculated with rhinovirus 16 via the nose. Subjects self-administered ColdZyme or placebo 6 times daily for 11 days. Symptoms were recorded daily in a diary. Rhinovirus 16 in nasal and oropharyngeal samples at days 0, 3, 4, 6, 7 and 10 were quantified by RT-qPCR. The primary outcome measure was the reduction in viral load in oropharyngeal samples. Rhinovirus 16 was only detected in 35 out of 46 inoculated subjects. Exploratory analysis measuring the total viral load (i.e., area under the curve (AUC)) for days 3 - 10 in successfully inoculated subjects found that ColdZyme treatment resulted in a lower total viral load in the oropharynx (p = 0.023). In subjects who experienced symptomatic common cold, irrespectively, if virus were detected, treatment with ColdZyme resulted in a reduction in the number of days with common cold symptoms from 6.5 to 3.0 days (p = 0.014) in comparison to placebo. ColdZyme reduced virus infection in the oropharynx and reduced the number of days with common cold symptoms and highlights the possible importance of the oropharynx in common cold infections. Suitable outcome measures for a feasible study on ColdZyme are total viral load in the oropharynx in subjects having detectable virus present in nasal or oropharyngeal samples.