Characteristics of Drugs Approved in Japan without Conducting
Confirmatory Clinical Trials
Abstract
Aims: The aim of this study was to investigate the characteristics of
drugs for which the requirement of confirmatory clinical trials for
approval was waived in Japan. We also aimed to identify factors and
formulae to predict the waiver of confirmatory clinical trials. Methods:
Data on approved drugs and their characteristics were mainly extracted
from the Japan Pharmaceuticals and Medical Device Agency database. The
seriousness of the disease, existence of available treatments, and
number of patients were considered as candidate factors. The influence
of each factor on receiving a waiver was determined using logistic
regression analysis comparing drugs approved with and without
confirmatory clinical trials as the binary response variable. The
predictive formula was derived from the results of the logistic
regression analysis. A receiver operating characteristic curve was used
to evaluate the accuracy of the prediction. Results: The drugs
categorised as anti-neoplastic agents, use of the cost accounting method
in the drug pricing system, ‘orphan’ designation, and Accelerated
Approval designation in the United States emerged as significant factors
in the logistic regression analysis, predicting a waiver for
confirmatory clinical trials (P < 0.001). These factors were
then used to establish a predictive model to ascertain whether
confirmatory clinical trials would be necessary for a new drug,
exhibiting good sensitivity (0.754) and specificity (0.785), and high
accuracy for newly approved drugs. Conclusion: The identification of key
factors that can predict waivers of confirmatory clinical trials may
accelerate the development of clinically important drugs and improve
patient access globally.