Efficacy and Safety of Zihua Wenfei Zhisou Granule in Treatment of Postinfectious Cough: A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Phase II Clinical Trial.

Objective: To evaluate the efficacy and safety of Chinese medicine (CM) Zihua Wenfei Zhisou Granule (ZWZG) in postinfectious cough (PIC) patients with CM syndrome of wind-cold invading Fei (Lung, WCIF).

Methods: This is a multicenter, randomized, double-blind, parallel-group, placebo-controlled phase II clinical trial. PIC patients with WCIF syndrome were recruited from the Respiratory Departments in 6 hospitals across China between March 2019 and December 2020. Eligible patients were randomly assigned to group A (ZWZG-matched placebo 15 g), group B (active ZWZG 15 g), and group C (active ZWZG 10 g plus ZWZG-matched placebo 5 g) in a 1:1:1 ratio. All medications were taken orally 3 times daily for 14 consecutive days. The primary outcomes were cough relief rate and cough disappearance rate. The secondary outcomes included time to cough relief, time to cough disappearance, and changes in cough symptom score (CSS), cough Visual Analog Scale (VAS) value, Cough-Specific Quality of Life Questionnaire (CQLQ) score, and CM syndrome score from baseline (day 0) to post-treatment (day 14). Adverse events (AEs) in each group were recorded.

Results: A total of 198 patients were included in the full analysis set (FAS) and safety analysis set (SS), while 183 were enrolled in the per-protocol analysis set (PPS). In the FAS population, the cough relief rate was 47.76%, 90.77% and 84.85% in groups A, B, and C, respectively; while the cough disappearance rate was 31.34%, 72.31% and 68.18%, respectively. The cough relief rates and cough disappearance rates in groups B and C were significantly higher than group A (P<0.0001). Both the median time to cough relief and cough disappearance in groups B and C were shorter than group A (P<0.0001). Compared with group A, groups B and C showed significantly greater improvements from baseline to post-treatment in CSS during daytime and nighttime as well as VAS (P<0.05). There were no significant differences in changes from baseline to post-treatment in CQLQ and CM syndrome scores among 3 groups (P>0.05). Results in the PPS population were consistent with those in the FAS population. Groups B and C showed lower incidence in AEs than group A (P<0.05), while there was no significant difference between groups B and C (P>0.05). No drug-related severe AEs were reported.

Conclusions: ZWZG can increase cough disappearance rate and cough relief rate; and it is beneficial in shortening cough duration and reducing cough severity and frequency in patients suffering from PIC. It is safe and generally well tolerated. (Registration No. ChiCTR1900022078).