submit original data." This shows the second aspect of the human food safety issue that stands in the way of "abbreviated" NADAS.

Although some of the efficacy issues may be resolved through the Drug Efficacy Study, it is FDA's position that human food safety data must be new and original. The sulfa notice indicates that in some cases actual clinical trials will be required to satisfy the human food safety requirements. Such studies are incompatible with the notion of an "abbreviated" NADA.

As noted earlier, FDA has permitted no new applicants since early 1975. Based upon this most recent Federal Register document, more than 10 years will have passed before the first "abbreviated" applicant (with its new human food safety data) will be able to come on the market.

3. An even more protracted proceeding has precluded any new interim marketers or abbreviated applications for various antibiotic drugs that are listed in 21 C.F.R. 558.15. Here again, the requirement for submitting applications and research commitments began in 1973; since that date, no new applications have been permitted pending FDA's resolution of the human food safety issues raised by many of the drugs listed in that section. As a result, there can be no abbreviated new drug applications for the products and combinations listed until the human food safety issues are resolved. This may not be for many more years, given the complexity of the issues relating to the safety of antibiotic residues in the human food chain.

The human food safety issues involving animal drugs can thus be seen to be complex, and their resolution time-consuming. These issues are an ongoing obstacle to the development of an abbreviated new animal drug application system. Unlike the human abbreviated new drug application system, where only data relating to manufacturing, good manufacturing practices and bioavailability are required, the new animal drug procedures require an independent demonstration of human food safety above and beyond efficacy and bioequivalence to the original drug product. These data are required to be original to each applicant, placing a significant economic burden on animal drug sponsors that does not exist with respect to human drugs.

The absence of any simplified system of demonstrating human food safety is a key reason why the time is not yet ripe for a statutory abbreviated new animal drug application provision.