Oncogenicity studies duration

Because of their size and duration and the corresponding costs involved, oncogenicity studies... 

Statistically, oncogenicity studies have a low sensitivity because of the small numbers of animals that are used. However, complex statistical analysis, which should include a judgement on whether the tumour was the cause of death, duration to death and trend analysis can reveal valuable information about the risk to man of taking the product therapeutically. 

If oncogenicity studies have been conducted by the oral route and another clinical route is to be used in man, the need to repeat such studies should be assessed critically. Oncogenic potential is related to the concentration of the carcinogen at its site of action. Thus, if the oral route results in adequate exposure of the lung, there should be no need to perform additional inhalation oncogenicity studies. Inhalation studies of 1-3 months duration should be performed to assess possible local effects on respiratory tissue and also to gain pharmacokinetic data. 

Because of their size and duration and the corresponding costs involved, oncogenicity studies are usually conducted towards the end of the development of a pharmaceutical when clinical efficacy has been established and the majority of the toxicity studies have been completed. The requirements in USA, Japan and Europe for clinical trials and marketing are compared in Table 3.4. 

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