An Analysis of Guidance for Proper Usage Documents for Oncology Drugs in Japan

Abstract

Pharmaceutical companies in Japan often provide a unique document called the Guidance for Proper Usage (GPU) to medical oncologists, in order to promote the proper use of an approved drug. The aim of the study was to examine the content of and current trends in the efficacy and safety data provided in GPU documents, in order to understand what pharmaceutical companies regard as important information for an oncologist to ensure proper usage of oncology drugs in Japan. Furthermore, this study analysed the influence of route of administration (oral or injection), drug class (cytotoxic or other), type of malignancy (haematological or solid malignancy) and the period of GPU publication (before and after April 2004) on the content of the GPU document. For the 103 oncology drugs approved for use in Japan, 59 GPU documents, covering 50 drugs, were distributed to medical oncologists and were compared by multivariate analysis over two consecutive time periods, from October 1994 to March 2004 and April 2004 to December 2010. For each document, we determined the total number of pages and the proportion of pages that provided drug and toxicity information and the results of registration trials, including postmarketing surveillance. The median number of pages in the GPUs was 48 (range, 11–98). The proportion of pages providing toxicity information, drug information (e.g. warnings, contraindications, instructions, and directions for indications and usage, dosage and administration) and the results of registration trials were 30%, 26% and 11%, respectively. After April 2004, the publication of GPU documents doubled, and the proportion of pages discussing the results of registration trials significantly increased (p = 0.002). The proportions of pages discussing toxicity information and the results of registration trials in molecular-targeted drugs were significantly greater than those for other types of drugs (p < 0.001 and p = 0.008, respectively), while the proportion of pages discussing drug information was significantly lower (p = 0.001). The number and length of GPU publications distributed by pharmaceutical companies in Japan has increased since 2004. Significant changes in content have included a reduction in the amount of information about drug administration and an increase in information on the results of pharmaceutical company-sponsored registrational trials. A further study is warranted to evaluate how often oncologists actually access GPU documents and what type of information could be most useful in medical practice in Japan.