CTD vs eCTD: Understanding the Backbone of Global Drug Submissions

CTD vs eCTD: Understanding the Backbone of Global Drug Submissions

When I first started learning about Regulatory Affairs, one of the most important concepts I discovered was the Common Technical Document (CTD), the universal structure that organizes all the data required to approve a medicine.
But as the world of regulatory submissions evolved, a new standard emerged: the electronic Common Technical Document (eCTD).
Although they serve the same purpose, they differ dramatically in format, management, and regulatory impact.
In this post, I’ll simplify the difference between CTD and eCTD and explain why every Regulatory Affairs professional must understand both.

2. What is the CTD

The Common Technical Document, or CTD, is a paper-based or electronic-PDF submission format developed by the International Council for Harmonisation (ICH).
It standardizes how pharmaceutical companies present data for new drug applications (NDAs), marketing authorization applications (MAAs), or biologics license applications (BLAs).

The CTD is divided into five modules:
Module 1: Regional Administrative Information (varies by region and is not harmonized)
Module 2: Summaries and Overviews
Module 3: Quality (CMC – Chemistry, Manufacturing, and Controls)
Module 4: Nonclinical Study Reports
Module 5: Clinical Study Reports

Key takeaway: The CTD brought global harmonization and made it possible for companies to prepare one global dossier usable in the US, EU, and Japan, with only Module 1 adjusted for each region.

3. What is the eCTD
The electronic Common Technical Document, or eCTD, is the digital evolution of the CTD.
Instead of sending thousands of paper pages, companies now submit an XML-based electronic structure where every document, hyperlink, and version is traceable and easy to update.

The eCTD allows:

• Structured electronic navigation through metadata
• Hyperlinks between documents and cross-references
• Lifecycle management, meaning you can submit updates (new data, corrections, labeling changes) without resending the entire dossier
• Faster review for agencies such as the FDA, EMA

Key takeaway: The eCTD isn’t just a digital CTD. It’s a submission management system that tracks versions, simplifies reviews, and enables real-time communication with authorities.