Unique characteristics of regulatory approval and pivotal studies of orphan anticancer drugs in Japan

Randomized Controlled Trial Data for New Drug Application for Rare Diseases in Japan

BACKGROUND

High-quality evidence is often not obtained in the clinical trials of rare diseases because these trials tend to be smaller in size and non-controlled. We investigated the potential factors associated with the need for randomized controlled trials (RCTs) in the clinical data package for new drug applications for rare diseases in Japan.

METHODS

This study focused on 130 drugs with orphan drug designation approved in Japan between April 2004 and March 2020.

RESULTS

Multivariable regression analysis showed that the prevalence (odds ratio [OR] 3.21, 95% confidence interval [CI] 1.18-8.6) and the type of primary endpoint (OR 6.66, 95% CI 2.41-18.37) were associated with the need for RCTs in the clinical data package in Japan.

CONCLUSIONS

Our findings highlight the importance of adequate understanding of the target disease in new drug development for rare diseases.

Safety-Related Regulatory Actions and Risk Factors for Anticancer Drugs in Japan

INTRODUCTION

The approval of anticancer drugs in Japan has increased to meet high medical demand. To maximize the benefits of anticancer drugs, adverse drug reactions (ADRs) must be properly managed. However, in some cases, clinically significant safety issues are detected after launch, and safety-related regulatory actions (SRRAs) are implemented.

OBJECTIVES

We aimed to determine the characteristics of SRRAs for anticancer drugs approved in Japan and to identify factors related to the drug development and regulatory approval process associated with the occurrence of an SRRA.

METHODS

We defined an SRRA as the issuance of a 'Yellow Letter', 'Blue Letter', or an official notification by the Ministry of Health, Labor and Welfare. Anticancer drugs approved in Japan as new active ingredients from April 2004 to July 2016 were analyzed using publicly available information. The Kaplan-Meier survival curve was plotted to estimate the probability of the occurrence of an SRRA, and the Cox proportional hazards model was used to identify risk factors associated with the occurrence of an SRRA. Independent variables were selected using backward/forward stepwise selection according to Akaike's Information Criterion.

RESULTS

An SRRA was implemented for 38 of 63 anticancer drugs. Approximately 70% of SRRAs occurred within 2 years after approval, and the median time between approval and the occurrence of an SRRA was 1.6 years (interquartile range 0.94-2.4). No Yellow Letter was issued during the follow-up period; however, one Blue Letter was issued for 'acute lung injury and interstitial pneumonia' for sorafenib. According to official notifications, 'clinically significant adverse reactions' was the most revised section of package inserts (62%). The probability of an SRRA at the 1-, 2- and 3-year follow-up was 15.9% (95% confidence interval [CI] 6.4-24.4%), 41.3% (95% CI 27.8-52.3%), and 56.8% (95% CI 41.8-68.0%), respectively. Monoclonal antibodies were associated with a low risk of occurrence of an SRRA (hazard ratio [HR] 0.29, p = 0.019), while the large number of patients in pivotal studies (per 100 patients) was associated with a high risk of occurrence (HR 1.07, p = 0.012).

CONCLUSIONS

The high-risk period for the occurrence of an SRRA for anticancer drugs in Japan was within 2 years after approval. Among the factors related to the drug development and regulatory approval process, anticancer drugs in the form of non-monoclonal antibodies, and whose pivotal studies included a large number of patients, were more likely to be associated with an SRRA. Postmarketing follow-up should therefore be carefully performed, especially in the first 2 years after approval and for non-monoclonal antibody anticancer drugs. Moreover, postmarketing follow-up is crucial, even if large-scale pivotal studies for regulatory approval have already been performed.

The drug lag and associated factors for orphan anticancer drugs in Japan compared to the United States

The approval of orphan anticancer drugs in Japan has increased to meet high social demand. Drug lag, namely the approval lag of new drugs, is recognized as a social issue in Japan. We investigated the approval lag and its components, submission lag and review-time lag, between Japan and the United States (US) to reveal whether an approval lag still exists, and to identify potential factors that may contribute to reducing the approval lag. Anticancer drugs approved in Japan between April 2004 and November 2017 were investigated using publicly available information. Results showed that the median approval lag of orphan anticancer drugs in 2016-2017 was 727.0 days (interquartile range, IQR, 310.0-1054.3). The approval lag was significantly correlated with the submission lag (correlation coefficient = 1.00, P < 0.001) but not with the review-time lag (correlation coefficient = -0.16, P = 0.22). The submission lag was significantly longer for orphan anticancer drugs than non-orphan drugs (median, 712.5 days [IQR, 186.0-1448.3] vs. 387.0 days [92.8-1096.0], P = 0.023). External collaboration in drug development was associated with a longer submission lag (coefficient = 762.1, P = 0.017), while breakthrough therapy designation in the US was associated with a shorter submission lag (coefficient = -832.8, P = 0.035). In conclusion, we revealed that an approval lag for orphan anticancer drugs still existed in 2016-2017. A submission lag for orphan anticancer drugs was the main component affecting the approval lag, and was longer than that for non-orphan drugs. External collaboration in drug development may be a potential factor in reducing the submission lag for orphan anticancer drugs.