The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) is a joint initiative involving both regulators and pharmaceutical-based industry representatives of the US, EU, and Japan to have scientific and technical discussions for drug registration and testing procedures required to assess and ensure the safety, quality and efficacy of medicines.

The ICH Efficacy (E) 3 is a harmonised ICH Guideline for Clinical Study Report (CSR) that was finalised in November 1995, which represents the integrated full report of the efficacy and safety data for an individual study with a therapeutic or diagnostic agent. It consists of a synopsis, core report and appendices. Additional direction was provided in the form of a question and answer (Q&A) supplement that was published in 2012that clarified few ambiguous issues. The ICH E3 guideline aims to allow the medical writer to draft the CSR that is complete, unambiguous, well-organized, and easy to review. It is a guideline and not a rigid requirement or a template. There may be a chance of presenting information that is missing, redundant, or suboptimal presentation, if the E3 is just used as a template without meaningful interpretation. The E3 guideline doesn’t give information on how the study results need to be drafted for certain type of studies (e.g., exploratory studies, pharmacokinetic studies, and studies with combination products). Hence, modifications and adaptations to the structure presented in the guideline for better presentation and communication of information is encouraged by the ICH, as long as important deviations from E3 are explained.

The CSR integrates the clinical and statistical descriptions, presentations, and analyses into a single integrated report, incorporating tables and figures. This integrated report not only outlines the original plan of the protocol, but also describes anything which was performed different from the originally planned, including any protocol deviation and violation. By reading the CSR, one can understand why and how the study was conducted, the types of data collected and analyzed, the results obtained in the study, and the nature and extent of the conclusions that are drawn from the results. The CSR is located within the Module 5 of Common Technical Document. The synopsis is a stand-alone document written to be read, understood and interpreted on its own without the other sections of a CSR. In the core report, there can be variations of the presentation of demographic baseline information (either be presented in the safety and efficacy sections or in a new section preceding the efficacy and safety results sections), pharmacokinetic or quality of life results (could be placed in the efficacy and safety results sections, or they could be placed in new, appropriately identified results sections). There are various appendices like protocol, case report form, audit certificate, statistical analysis plan, listings etc. that need to be added.

Some of the studies conducted during product development may be terminated in between and may warrant an abbreviated CSR instead of full CSR submission to the regulatory authorities. In this case, ICH E3 may not be that useful as it provides information only on the structure and content of full CSRs. Hence, for abbreviated CSR submission, a guideline issued by the United States Food and Drug Administration may be used. Nowadays, there are requirements of disclosure of clinical study results; the CSR is the first document that gets disclosed. Hence, another guideline Clarity and Openness in Reporting (CORE) Reference E3-based was published and includes detailed content suggestions and practical suggestions for developing CSRs that will require minimum redaction and modification prior to public disclosure.