A total of 67 trials (including 4 phase Ⅰ, 20 phase Ⅱ, 26 phase Ⅲ, and 11 phase Ⅳ trials) were conducted among children age ranging from 0 to 18 years. Ten trials included both adults and children as subjects, and 179 trials (including all 160 bioequivalence trials) included only adults as subjects. A simple regression model revealed that the overall average annual growth rate of the number of trials was 43.30% (P=0.0000). As shown in figure 1, the number of trials included had been significantly increased since 2017. In addition, a simple regression model based on the number of phases I to IV trials showed an average annual growth rate of 22.12% (P=0.001).
Geographical locationof the trials with indications for children in China
The geographical distribution of the sponsors of the 256 trials was shown in figure 2. More than 40% of the sponsors were located in the eastern China. The geographical distribution of the principal investigator involved in the 256 trials was shown in figure 3, and the trial institutions were mainly distributed in the east, the north and the central China, with Beijing, Jiangsu and Shanghai as the major ones.
Distribution of the studied drugs and its dosage form
The types of research drugs involved in the 256 trials and the distribution of the main dosage forms were shown in figure 4. The drug types mainly included were the chemical drugs, accounting for 76.17%. Based on the age of indications, there were 102 drugs used for children under 18 years age, i.e. children-specific drugs (39.84%), in which 3 drugs were used for premature infants and newborns, namely caffeine citrate, porcine lung surfactant and hepatitis B vaccine, and 11 drugs were used for only infants. The remaining 154 (60.16%) drugs were indicated for both adults and children. Considering the dosage forms of the 195 chemical drugs, tablets were the main ones, followed by capsules, injections and granules. The other dosage forms were shown in fig. 4 included syrup, powder, oral solution membrane and needle-free percutaneous injection administration system, respectively. All traditional Chinese medicine/natural drugs were special drugs for children, and their dosage forms mainly included granules and patches. Of the 40 kinds (15.63%) of biological products, 33 were specific drugs for children, mainly in the form of injections.