Toxicological Principles for the Safety Assessment of Food Ingredients
Chapter IV.C.7. Combined Chronic Toxicity/Carcinogenicity Studies with Rodents
Return to Redbook 2000 table of contents
This section of Redbook 2000 supersedes the 1993 "draft" Redbook Chapter IV.C.7. The FDA acknowledges that it is complicated and difficult to conduct a combined chronic toxicity/carcinogenicity rodent study particularly with an in-utero exposure phase. This is often due to difficulty in setting and administering appropriate dose levels for both types of studies concurrently. Additionally, the general objectives of these two types of studies are different. Nevertheless, when pre-chronic studies provide reasonable estimates of toxicity to predict the information (i.e., treatment doses) to be used in a single bioassay, a chronic toxicity study may be combined with a carcinogenicity study and reveal information about an ingredient's potential to be a carcinogen as well as the maximum dose that produces no adverse effects.
The FDA recommends that the petitioner/notifier consult with the FDA before conducting a combined study. Sponsors/submitters of petitions/notifications are also encouraged to become familiar with the Guidance for Chronic Toxicity Studies with Rodents (Chapter IV.C.5.a.), Carcinogenicity Studies with Rodents (Chapter IV.C.6.), In-Utero Exposure Phase for Addition to Carcinogenicity Studies or Chronic Toxicity Studies with Rodents (Chapter IV.C.8.), Reporting Results of Toxicity Studies (Chapter IV.B.2.), Pathology Considerations in Toxicity Studies (Chapter IV.B.3.), and Statistical Considerations in Toxicity Studies (Chapter IV.B.4.) during the development of study design.