Efficacy and safety of Qing-Feng-Gan-Ke Granules in patients with postinfectious cough: study protocol of a novel-design phase III placebo-controlled, double-blind randomized trial.
BACKGROUND
Postinfectious cough (PIC) is a common condition that affects millions of people worldwide every year. There is Western medicine for this condition but the treatment effect is often incomplete. Traditional Chinese medicine (TCM) has been increasingly prescribed for patients with PIC. Preliminary trials on Qing-Feng-Gan-Ke-Granules (QFGKG) conveyed promising results in treating PIC. This protocol describes an ongoing phase III randomized controlled clinical trial, designed according to a novel methodology of "one study, one primary outcome", with the objective of evaluating the efficacy and safety of QFGKG in patients suffering from PIC.


METHODS
This is a multicenter, phase III, randomized, double-blind, parallel-group, placebo-controlled clinical trial, comprising two simultaneously conducted study parts, part A and part B, intending to investigate two primary outcomes, i.e. time to cough resolution and cough symptom score, respectively. A total of 480 patients, aged 18 to 65 years, who complain of an ongoing persistent cough that has been lasting ≥ 3 weeks, will be recruited from six participating sites and then randomized to receive QFGKG 12.0 g twice daily or placebo 12.0 g twice daily. Each part will enroll 240 patients, with 180 patients being allocated to the QFGKG group and 60 to the placebo group.


CONCLUSIONS
Although traditional Chinese medicine is a structured intervention that has shown some promise in treating persistent cough, existing unconvincing evidence has noted limitations. This is a rare well-designed and rigorously-controlled, randomized, double-blind trial to evaluate the effects and safety of a Chinese herbal medicine in patients with postinfectious cough, providing tangible benefits for clinical research. Results of this trial are inclined to be conjectured as more truthful by implementing separate study parts that specifically estimate exclusive primary outcome. It will not only provide robust clinical evidence on the efficacy and safety of QFGKG for postinfectious cough, but will also provide a critical piece of information on the availability and superiority of a novel methodology for future clinical trials. The current trial is ongoing with recruitment of the predetermined number of patients being in progress.


BACKGROUND
The two parts of this trial were separately registered with the Chinese Clinical Trial Registry: ChiCTR-TRC-13003278 (part A); and ChiCTR-TRC-13003337 (part B).
Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu, Sichuan Province, 610041, China. lovekk_cool@126.com.
Wei
W
Liu
Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu, Sichuan Province, 610041, China. 81489337@qq.com.
Hongli
H
Jiang
Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu, Sichuan Province, 610041, China. zhruim-001@163.com.
Ruiming
R
Zhang
Department of Respiratory and Critical Care Medicine, Tangdu Hospital of The Fourth Military Medical University, 1 Xinsi Road, Xi'an, Shaanxi Province, 710038, China. jinfag@fmmu.edu.cn.
Faguang
F
Jin
Department of Respiratory Medicine, Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, 445 Bayi Avenue, Nanchang, Jiangxi Province, 330006, China. llj6505@163.com.
Liangji
L
Liu
Department of Respiratory Medicine, The Second Affiliated Hospital of Tianjin University of Traditional Chinese Medicine, 816 Zhenli Street, Tianjin, 300150, China. longyou@eyou.com.
Youyu
Y
Long
Department of Respiratory Medicine, Affiliated Hospital of Inner Mongolia Medical University, 1 North Tongdao Street, Hohhot, Inner Mongolia, 010000, China. cuiliying306@hotmail.com.
Liying
L
Cui
Department of Respiratory Diseases, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, 19 Renmin Road, Zhengzhou, Henan Province, 450000, China. lisuyun2000@yahoo.com.cn.
Suyun
S
Li
Department of Respiratory Medicine, The First Affiliated Hospital of Guangxi University of Traditional Chinese Medicine, 89-9 Dongge Road, Nanning, Guangxi Province, 530023, China. jackvictor666666@163.com.
Yunqing
Y
Zhong
Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu, Sichuan Province, 610041, China. maobing2013@yeah.net.
Bing
B
Mao
D000293:Adolescent; D000328:Adult; D000368:Aged; D003371:Cough / Q000188:drug therapy*; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D008875:Middle Aged; D055815:Young Adult
D004365:Drugs, Chinese Herbal