Preclinical studies are essential for the development of all drug candidates. In general, CTAs contain fewer study documents than INDs, and hence require less preparation time.
Both IND and CTA submissions aim to enable clinical trials, but they have different requirements.
An IND can be opened with a study of any phase and it includes multiple forms specific to the FDA, all nonclinical study reports, nonclinical summaries, detailed CMC information, the protocol and Investigator’s Brochure (IB). Once an IND has been cleared by the FDA, multiple studies can be conducted under the same IND. For drugs that are in very early development, an exploratory IND, supported by limited nonclinical data, may be submitted to allow evaluation of up to five APIs simultaneously. Furthermore, some research studies may not require IND submission at all.
The EMA has set regulations differently as each interventional clinical study requires its own CTA. This, partly, helps explain why the documentation required for these submissions is not identical. For a CTA, the four main documents are the protocol, informed consent form, IB, and Investigational Medicinal Product Dossier (IMPD), which contains CMC data. In addition to these, other documents such as EU-specific forms, questionnaires and insurance certificates must be included.