Potential factors correlating to the PMDA's decision to waive Japanese Phase 2 and 3 studies for oncology drugs New Drug Application in Japan.

Current status of oncology drugs approved in Japan without supporting Japanese Phase 2 and 3 clinical trial (J-P2/3) data and potential factors correlating to the decision of Japanese health agency Pharmaceuticals and Medical Devices Agency (PMDA) to waive J-P2/3 data were investigated. Approximately 15 % of 61 investigated recently-approved oncology drugs were granted a J-P2/3 waiver. Drugs that were designated as Fast Track in the United States tended to be granted a J-P2/3 waiver. The orphan drug designation in Japan was also suggested to be correlated with the decision of J-P2/3 waiver, even though the trend was not significant. Specific factors related to the clinical importance, such as the designation of US Fast Track status, may have a correlation with the likelihood of J-P2/3 waiver, suggesting that the clinical importance of the drug is common in both countries. If the key criteria used to determine the waiving of Japanese clinical trial data were clearly disclosed by the regulatory agency, the development of some clinically important oncology drugs could be further expedited.

The Relationship Between Development Start Lag and Approval Lag in Oncology Drug Development in Japan.

BACKGROUND: The delay of initiation of clinical development is considered a causes of delay of approval of drugs (drug lag) in Japan. METHODS: For oncology drugs newly approved between 2000 and 2012 in Japan, a possible impact of delay of initiation of clinical development (development start lag [DSL]) on delay of approval (approval lag [AL]) was investigated, focusing on the delay from the US timelines. The equation defining the relationship between the DSL and AL of 33 oncology drugs was calculated by using simulation models, then the Pearson coefficient of correlation between parameters was calculated. RESULTS: From the analysis of all drugs investigated, a positive relationship between the DSL and AL was suggested. However, the relationship seemed to have 2 phases, including a flat phase, followed by a linearly increased phase with a breakpoint at 2340 DSL days (approximately 6.4 DSL years). CONCLUSIONS: Shortening the DSL is important for reducing large AL, but it is not necessary to eliminate the DSL completely for the purpose of minimizing the AL.