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CTD(Common Technical Document)

Common Technical Document is the ICH-harmonized dossier structure that fixes what content belongs in each of five modules of a drug application, letting one technical package serve regulators across the ICH regions.

Usage Examples

  • Module 3 of the CTD is written once and reused, but Module 1 gets rebuilt for every region we file in.
  • That benefit-risk narrative belongs in CTD section 2.5.6, not buried at the back of the clinical summary.
  • We are CTD-ready on content; it is the eCTD publishing that is not booked yet.

What is CTD (Common Technical Document)?

Common Technical Document is the ICH-harmonized dossier structure that fixes what content belongs in each of five modules of a drug application, letting one technical package serve regulators across the ICH regions.

Common Technical Document exists because the same dossier used to be rebuilt three times for three regions. FDA's notice adopting ICH M4 states the CTD is intended to reduce the time and resources used to compile applications, ease the preparation of electronic submissions, facilitate regulatory reviews and communication with the applicant, and simplify the exchange of regulatory information among regulatory authorities.

Common Technical Document covers the organization of a marketing application across five modules: administrative information, summaries, quality, nonclinical study reports, and clinical study reports. CTD is a content standard, not a transport format, and its harmonization stops at Module 1, which ICH M4 reserves as a region-specific module that will not be harmonized. Modules 2 through 5 travel; Module 1 does not.

Common Technical Document is applied as a placement discipline, not a writing exercise. Each fact has one correct address: benefit-risk conclusions belong in the Clinical Overview at CTD section 2.5.6, and quality detail sits in Module 3 under the granularity rules FDA revised in October 2017. CTD-fluent teams settle where content lives before they argue about how it reads.

Not to be confused with

eCTD
eCTD is the electronic format that carries CTD content and adds file-level versioning; CTD is the content standard that says what goes where. A dossier can be correct as CTD content and still fail eCTD validation, and a clean eCTD can still have a study report in the wrong module.
ICH M4
M4 is the guideline, the CTD is the structure M4 defines. FDA adopted M4 in parts (organization, M4Q quality, M4S safety, M4E efficacy), each with its own revision and date, so "we follow the CTD" never specifies which version of which part you built to.
Module 1
Module 1 sits inside the dossier but outside the harmonized CTD. ICH M4 reserves it as region-specific and explicitly does not harmonize it, so an FDA Module 1 is not a starting point for another agency.
NDA or BLA
an NDA or BLA is the application itself, a legal filing type with its own evidentiary burden. The CTD is only the structure that application is organized in. Changing format never changes what the application must prove.

CTD obligations come from the ICH M4 parts FDA has adopted as guidance.

What you must do

  1. 1Organize new product applications, including biotechnology-derived products, in the harmonized CTD format used by the regulatory authorities in the three ICH regionsICH M4
  2. 2Build Module 1 separately for each region and never assume it transfers, because it is reserved as region-specific and is not harmonizedICH M4 Module 1
  3. 3Apply the current granularity rules to Module 2.3 Quality Overall Summary and Module 3 Quality as revised in October 2017, noting that Modules 4 and 5 were not changedICH M4 (October 2017 revision)
  4. 4Place benefit-risk conclusions in the Clinical Overview of Module 2 under CTD section 2.5.6, structured as therapeutic context, benefit, risk, and benefit-risk assessmentICH M4E(R2) section 2.5.6
  5. 5Track M4Q(R2) but do not rebuild the quality module against it, because FDA issued it as draft guidance on 21 January 2026 with comments due 23 March 2026ICH M4Q(R2) (draft)

Common mistakes

  • Treating the CTD as a formatting pass after the science is done

    placement decisions are content decisions. A study report filed under the wrong module, or a benefit-risk narrative outside section 2.5.6, reads to a reviewer as missing rather than misplaced. The information request that follows costs a review cycle, not an afternoon of repagination.

  • Reusing Module 1 across regions

    ICH M4 reserves Module 1 as a region-specific module that will not be harmonized. Teams who budget a single publishing pass for a multi-region program find a second forms set, a second regional structure, and a second validation profile waiting at the point in the timeline with the least slack.

  • Building the quality module against draft text

    FDA issued M4Q(R2) as a draft guidance on 21 January 2026, with comments due 23 March 2026. Restructuring Module 3 around draft text strands that work if the final version differs, and the operative requirement remains the October 2017 revision until FDA finalizes it.

When This Matters

  • Module 3 of the CTD is written once and reused, but Module 1 gets rebuilt for every region we file in.
  • That benefit-risk narrative belongs in CTD section 2.5.6, not buried at the back of the clinical summary.
  • We are CTD-ready on content; it is the eCTD publishing that is not booked yet.

Frequently Asked Questions

CTD is the content standard and eCTD is the electronic format that carries it. ICH M4 defines what belongs in each of the five modules; eCTD specifies how those files are structured, transmitted, and versioned. FDA requires eCTD for NDAs, ANDAs, and BLAs since 5 May 2017.

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