SEND, short for Standard for Exchange of Nonclinical Data, is the CDISC standard for the exchange and submission of nonclinical study data. It organizes tabulation datasets from preclinical investigations into a uniform structure that is modeled after SDTM. SEND thus concerns data from animal and laboratory studies prior to or alongside clinical development, not data from study participants.
This supports the technical comparability of nonclinical findings across project and organizational boundaries.
Nonclinical Data in Standardized Tabulations
The SEND Implementation Guide describes how data from single-dose and repeat-dose toxicology, carcinogenicity, and respiratory and cardiovascular safety pharmacology studies can be structured. Further guides address specific types of investigations, such as developmental and reproductive toxicology, genetic toxicology, or studies conducted under the Animal Rule. The starting point is nonclinical findings, observations, and measurements, which are converted into standardized datasets.
In the data flow, SEND is positioned after the execution and evaluation of individual nonclinical studies, but before electronic exchange with other organizations or regulatory submission. Its tabular form allows studies from different laboratories and sponsors to be brought to a comparable review level. The standard does not change the GLP status of an experiment and does not replace study planning or toxicological interpretation.
Relationship to SDTM and Conformance Rules
SEND is based on the SDTM model but is concretized with nonclinical domains and implementation specifications for its own application area. CDISC develops each SEND Implementation Guide in relation to a specific SDTM model. This common model basis creates related principles for organization, variables, and metadata, without equating clinical and nonclinical datasets.
CDISC also publishes conformance rules that support the technical review of SENDIG datasets. Such rules can detect format or structural deviations but do not fully assess whether a dataset correctly represents the entire technical scope of a study. Therefore, knowledge of study design, species, dose groups, time points, and endpoints remains essential for delivery.
Nonclinical studies generate heterogeneous data: animal identifications, test articles, dose groups, macroscopic and microscopic findings, and safety pharmacology findings must be interpreted in the correct study context. SEND provides the structure for transmitting such information, including metadata. However, the actual toxicological conclusion is drawn from study data, study report, and scientific evaluation, not solely from a data format.
For exchange, the complete description of the datasets is particularly important. The FDA specifies Define-XML for the metadata of submitted SEND datasets. A technical package must therefore explain, in addition to the tables, which variables, controlled terminology, and origin-related rules were used. This allows data reviewers to classify the nonclinical content without knowledge of local laboratory designations.
Distinction from SDTM, Preclinical Development, and GLP
SDTM describes clinical tabulation data from human studies; SEND is aimed at nonclinical animal and laboratory studies, which investigate, for example, the toxicological properties of an active substance. Both standards use related model principles but serve different data spaces and submission contexts. A SEND dataset is therefore not an alternative designation for an SDTM dataset.
Furthermore, SEND is neither a study phase nor a quality standard. Preclinical development refers to the development phase involving nonclinical investigations. GLP, Good Laboratory Practice, regulates quality requirements for specific types of studies. In contrast, SEND defines a data format and the associated structure with which the results of such a study can be provided.
The selection of a SENDIG depends on the study type and the findings to be submitted. If multiple nonclinical study types are combined, each data delivery must be checked against the relevant guide and the intended metadata.
Careful pre-screening before submission reduces technical queries during regulatory review.
Relevance for clinical trials
Although SEND primarily concerns nonclinical development, it influences clinical programs through the regulatory preparation of an investigational medicinal product. Toxicological studies, with their metadata, animals, dose groups, samples, and findings, must be available in a way that allows a regulatory authority to understand the safety basis. Relevant project tasks include coordination of data transfers with nonclinical service providers, review of data delivery plans, quality control of SEND packages, and integration with regulatory submission documents. During transitions to first-in-human planning, they can also ensure that nonclinical safety data and their descriptions are consistently referenced in the relevant dossiers.
Full-service CROs like Mediconomics support SEND-related work through coordination of data transfers with nonclinical service providers, review of data delivery plans, quality control of SEND packages, and integration with regulatory submission documents. During transitions to first-in-human planning, they can also ensure that nonclinical safety data and their descriptions are consistently referenced in the relevant dossiers.
Frequently Asked Questions (FAQ)
Are data from a clinical Phase I study delivered in SEND?
No. Human studies are generally structured according to SDTM for tabular submission. SEND refers to nonclinical investigations.
Is SEND only for toxicology?
The core area includes several nonclinical study types, including general toxicology and safety pharmacology. CDISC also provides additional guides for specific data types.
Does a SEND format make a GLP inspection superfluous?
No. SEND standardizes data exchange. Compliance with GLP and the evaluation of study conduct are neither replaced nor automatically proven by it.
Regulatory References
- CDISC Standard for Exchange of Nonclinical Data – defines the basic structure of nonclinical tabulation data.
- CDISC SEND Implementation Guides – concretize SEND for general and specific nonclinical study types.
- CDISC SEND Conformance Rules – support the technical conformance review of SEND datasets.
- FDA Study Data Technical Conformance Guide – assigns SEND to nonclinical toxicological tabulation data.
