Analysis of Safety-Related Regulatory Actions for New Drugs in Japan by Nature of Identified Risks

Characteristics on Drug Safety Measures in Japan Stratified by System Organ Classes and Therapeutic Categories in Relation to the Approval Date

Revisions of drug package inserts (PIs) may be made immediately after approval or after considerable clinical experience; however, it is unclear whether there is a relationship between the characteristics of these safety measures and the period since drug approval. Here, we analyzed 209 cases of safety measures (revisions of the PIs) taken in Japan over 5 years (FY2014 to FY2018). The median, minimum, and maximum period from approval date in Japan to PI revision date was 6.29 years (interquartile range 2.68-15.53 years), 0.16 years, and 59.69 years, respectively. The cases were classified into four groups depending on types of adverse reaction and therapeutic category in relation to the national approval date and international birth date, resulting in the grouping together of particular adverse reactions and therapeutic drugs. For example, "Hepatobiliary disorders", "Blood and lymphatic system disorders", "Respiratory, thoracic and mediastinal disorders", "Antineoplastics", "Chemotherapeutics", and "Other agents affecting metabolism" were associated with the group of safety measures taken early after approval of a drug soon after the international birth date, suggesting that careful attention at an earlier stage after approval is necessary for these adverse reactions and drugs. Understanding such features of PI revisions makes pharmacovigilance planning more appropriate, contributing to the implementation of rapid and proper safety measures after drug approval.

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.

Analysis of Global Drug Development Pathways and Postmarketing Safety in Japan: Local Studies May Reduce Drug-Related Deaths

Recent International Conference on Harmonization (ICH) guidelines provide pharmaceutical companies with regulatory justifications to pursue various global drug‐development pathways, in some of which “local” dose‐ranging and/or pivotal phase III studies are skipped. We examined the association between the clinical development pathway and postmarketing safety in Japan for 177 new molecular entities approved between 2004 and 2013 focusing on dose setting histories for each drug. The risk of drug‐related deaths was higher when companies did not conduct local (i.e., Japanese) dose‐ranging studies and/or pivotal studies. Even when local dose‐ranging studies were conducted, the risk remained higher in some drugs for which the approved dose in Japan was set equal to that in the United States. Drugs developed under a bridging strategy tended to show lower risks. These results suggested that local clinical studies may play a substantial role in achieving optimization of postmarketing drug use in each local target population.