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SEND

Purpose

The The purpose of the SDTM Trial Design Model in the SENDIG provides a standardized way to describe those aspects of the planned conduct of a nonclinical study, as shown in the study design diagram examples within this section. The Trial Design Model in the SENDIG is equivalent to the Trial Design Model within the SDTMIG for clinical trials. is to represent a brief, clear description of the overall plan and design of studies of tobacco products. Trial Design datasets contain study-level, rather than subject-level, information. Note that generally the term "trial" is equivalent to "study" in the nonclinical context. In addition, "subjects" are equivalent to "animals."
The Trial Design Datasets will allow:

  • Clear and quick understanding of the design of nonclinical studies (or trials)
  • Comparison of the designs of different studies (or trials)
  • Comparison of planned and actual treatments and sponsor-defined groups for subjects (or animals) in a study (or trial)

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Trial Design Concepts

A nonclinical study is a scientific experiment, typically involving animal subjects, which is intended to address certain scientific questions that are the objectives of the study.

Branch:

In a study with multiple Arms, the protocol plans for each subject to be assigned to one Arm. The time within the study at which this assignment takes place is often the point at which Arms with common Elements diverge into uncommon or nonshared Elements, and is referred to as a branch point. Many studies have a single branch point. Subjects are assigned to an Arm all at the same time. For other studies, there may be two or more branches that collectively assign a subject to individual Arms. The process that makes this assignment may be a randomization, but this is not always the case, as branch points are protocol-defined.

Element:

An Element is a basic building block in the study design. All Elements are related to the administration of planned interventions, which may involve treatment or no treatment, during a period of time. Elements for which the planned intervention does not involve treatment would include screening, washout, and recovery.

Epoch:

As part of the design of a study, the planned periods or phases of subjects' participation in the study are divided into Epochs. Each Epoch is a period of time that serves a purpose in the study as a whole. Typically, the purpose of an Epoch will be to expose subjects to a treatment, or to prepare for such a treatment period (e.g., pretreatment or screening period, wash out previous treatments) or to gather data on subjects after a treatment has ended (e.g., recovery phase). It is possible for Epochs to span multiple Elements for some or all Trial Arms present on a study. For example, there may be two sequential (but different) treatment Elements planned for a group; the sponsor might choose to include both of these in a single treatment Epoch.

Treatments:

The word "treatment" may be used in connection with Epochs or Elements, but has somewhat different meanings in each context:

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datasets based on the Trial Design Model describe the planned design of the study and provide the representation of the study product in its most granular components, as well as the representation of all sequences of these components as described in the protocol. 

Guidance in this section is applicable to TIG Nonclinical and Product Impact on Individual Health use cases only.In this section, the term "trial" is equivalent to "study". The TIG guides implementation of the Trial Design datasets described in the following table for use cases as indicated. 

Metadataspec
NumDatasetDescriptionUse Case(s)
1Trial Arms (TA)

Represents each planned arm in the study including the sequences of elements in each epoch for each arm. The TA and TE datasets are interrelated and provide the building blocks for subject-level information.

  • Nonclinical
  • Product Impact on Individual Health
2

Trial Elements (TE) 

Represents the elements used in the study including unique codes for each element, element descriptions, and the rules for starting and ending an element. The TA and TE datasets are interrelated and provide the building blocks for subject-level information.

  • Nonclinical
  • Product Impact on Individual Health
3Trial Visits (TV)Represents the planned order and number of visits in the study within each arm 
  • Product Impact on Individual Health
4Trial Inclusion/Exclusion (TI)

Represents the inclusion and exclusion criteria for the study


  • Product Impact on Individual Health
5Trial Summary (TS)

Represents key summary characteristics for the study

  • Nonclinical
  • Product Impact on Individual Health
6Trial Sets (TX)

Represents planned sets of subjects (e.g., in vivo studies) or sources of information (e.g., in vitro studies) that result from combinations of experimental factors defined for the study 

  • Nonclinical

Trial Arm:

A Trial Arm is a planned path through the study based upon a planned sequence of Elements. This path covers the entire time of the study. Each sponsor-defined protocol group may contain subjects from several Arms, one Arm, or part of an Arm. Each subject is assigned to one and only one planned Arm.

Trial Design:

The design of a study is a plan outlining the activities subjects will experience and what data will be collected during the course of the study in order to address the study's objectives.

Trial Group:

A group describes the sponsor-defined protocol structure commonly used in nonclinical studies, where study subjects are allocated to study groups within the study protocol. These groups may be defined for a variety of experimental purposes. Groups are frequently defined to separate subjects receiving different treatments, but there may be other considerations involved in the design of any particular study. For purposes of SEND, a Trial Group is a collection of subjects which have been designated with the same sponsor-defined protocol group code. A Trial Group consists of one or more Trial Sets.

Trial Set:

A Trial Set is a collection of subjects that have a common set of parameters defined in the protocol, where those parameters include experimental parameters (such as diet restriction), treatment parameters, and/or sponsor-defined attributes (such as control group designation). There should be no planned parameters of interest that could further subdivide a Trial Set. Each subject must be assigned to one and only one Trial Set. Each Trial Set should be assigned to a single Group. Each Set should be assigned to a single Trial Arm.

Trial Summary:

As part of the Trial Design datasets, Trial Summary provides important or key study-level information.

SDTM

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  • Because epochs cut across arms, an epoch treatment is at a high level that does not specify anything that differs between arms. For example, in a 3-period crossover study of 3 doses of drug X, each treatment epoch is associated with drug X, but not with a specific dose.
  • A study cell treatment is specific to a particular arm. For example, a parallel trial might have study cell treatments placebo and drug X, without any additional detail (e.g., dose, frequency, route of administration) being specified. A study cell treatment is at a relatively high level, the level at which treatments might be planned in an early conceptual draft of the trial, or in the title or objectives of the trial.
  • An element treatment may be fairly detailed. For example, for an element representing a cycle of chemotherapy, element treatment might specify 5 daily 100 mg doses of drug X.

The distinctions between these levels are not rigid, and depend on the objectives of the trial. For example, route is generally a detail of dosing, but in a bioequivalence trial comparing IV and oral administration of drug X, route is clearly part of study cell treatment.

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