SDTM: DIFFERENCE BETWEEN EX AND EC DATASETS

SDTM: DIFFERENCE BETWEEN EX AND EC DATASETS

Clinical trial study designs can range from open label to blinded. In open label studies, subjects and investigators know which product, each subject is receiving. Whereas, in blinded studies, the subject, investigator, or anyone assessing the outcome is unaware of the treatment assignment(s) to reduce potential for bias. To support standardization of various collection methods and details, as well as process differences between open-label and blinded studies, two SDTM domains based on the Interventions General Observation Class are available to represent details of subject exposure to protocol-specified study treatment(s). Exposure (EX) and Exposure as Collected (EC)

If the collected exposure information is not exactly same as the protocol specified study treatment administration details, then these should be mapped to different domains. Ie, Protocol specified exposure details should be mapped to EX domain and exposure as collected information should be mapped to EC domain.

The below examples describe different scenarios for making use EX and EC datasets meaningfully.

Example 1

This is an example of a double blind study comparing Drug A (two 250-mg tablets once daily) vs, Drug B (two 100 mg tablets once daily). For this study, the CRF information given is,

Subject A001 took 2 tablets from Bottle A from 2014-01-01 to 2014-01-15 and Subject A002 took 2 tablets from Bottle B within the same timeframe but missed dosing by subject’s mistake on 2014-01-11.

Since this is the blinded study, in the CRFs, it is not revealed that which drug is taken by subjects rather given the information of bottle number. When mapping this to SDTM, these information will get into EC dataset.

The corresponding SDTM EC dataset will be as follows:

sdtm

sdtm

Note: The reason for dose missing (Subjects mistake) should be mapped to SUPPEC.

Suppose, after unmasking done on this study and it is revealed that Subject A001 received Drug A and Subject A002 received Drug B. ie, Subject A001 took 500 mg of Drug A tablets daily and Subject A002 took 200 mg of Drug B tablets daily.

This can be mapped to EX domain as follows:

sdtm

sdtm

Here, the dose Subject A002 did not take on 2004-01-11 is not represented as a record in the EX dataset, because it is reflected as a gap in time between Row 2 (EXENDY relative day 10) and Row 3 (EXSTDY relative day 12).

Example 2

This is an example of an open-label study design where Drug A (10 mg/mL solution) is administered across 3 injection sites to deliver a dose of 3 mg/kg.

As per protocol 3 mg/kg dose Drug A should be delivered to each subject. So, for the subject A001 who has a weight of 50 kg, the dose should be delivered is 150mg. Here, the study is designed to administrate Drug A solution (10 mg/mL) through 3 injection sites. To deliver 150mg dose, 15 mL solution should be administrated to this subject and is given through 3 injections (administrated 5 mL each).

CRF information for the subject ABC3001 is given below:

 

Visit3
Date2014-01-01
Injection 1
Volume Given (mL)5
LocationABDOMEN
SideLeft
Injection 2
Volume Given (mL)5
LocationABDOMEN
SideCenter
Injection 3
Volume Given (mL)5
LocationABDOMEN
SideRight

 

This collected data will be mapped to EC dataset and is as follows:

sdtm

sdtm6

When considering EX domain for this case, a single EX record will be reflected because the sponsor considered the 3 injections as a single administration (as per protocol, the drug administrated to the subject is Drug A of dose 3mg/kg).

The following shows the corresponding EX dataset:

sdtm

sdtm

Note: If the sponsor chose to represent the laterality values, then it can be done by following General Assumption for handling multiple values for non-result qualifier variables.

 

 

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