Methods and findings
SORE THROAT, COMMON COLD, COMMON COLDS, SECONDARY
This was a double-blind, randomized, parallel-group, placebo-controlled study conducted at 10 German sites to evaluate the efficacy of the medical device ColdZyme, a glycerol mouth spray containing cold-adapted cod trypsin for a naturally occurring common cold versus placebo spray. Adults experiencing a minimum of three common colds during the previous year, but otherwise healthy, were enrolled to begin treatment with the mouth spray or placebo six times daily at first sign of a common cold. Jackson’s symptom scale and the 9-item Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21) quality of life (QoL) domain and a sore throat scale were recorded daily by subjects, as well as any use of allowed rescue treatment.Between January and April 2019, 701 subjects were enrolled and randomly assigned to the ColdZyme group (n = 351) or the placebo group (n = 350). Of the 701 subjects, 438 (62.5%) subjects developed symptoms typical of common cold, and all 438 started study treatment (n = 220 in the ColdZyme group and n = 218 in the placebo group). The demographic profile of the treatment groups were comparable with 68.1% female and almost all subjects being Caucasian (98.4%). The age ranged between 18 and 70 years with a mean age of 41.3 (±14.4) years.There were no differences between the groups in primary and major secondary endpoints, however, the assessment using the WURSS-21 QoL domain and Jackson score suggests a slightly faster recovery with ColdZyme as symptoms and complaints affecting the quality of life were shortened by about 1 day. The beneficial effect of ColdZyme was particularly noticeable on the fifth day of the common cold. A positive difference between treatment groups was also seen for the subjects’ assessments of global efficacy of the investigational product A robust safety profile for ColdZyme was demonstrated throughout the study.