Managing MedDRA Version Updates in Clinical Trials

Why MedDRA Versions Are Updated

The Medical Dictionary for Regulatory Activities (MedDRA) is updated twice a year—typically in March and September. These updates ensure that the dictionary evolves with medical science, incorporating new terms, restructuring hierarchies, and refining definitions. For sponsors, CROs, and regulators, version updates improve data accuracy, harmonize coding, and support signal detection across therapeutic areas.

Updates may include new Preferred Terms (PTs), modifications to System Organ Classes (SOCs), or reclassification of existing terms. For example, emerging conditions such as “COVID-19 pneumonia” were added in recent versions. Sponsors must adopt these updates in a timely manner to remain compliant with regulatory expectations. Agencies such as the FDA, EMA, and PMDA require that safety data submissions specify the MedDRA version used for coding.

Failure to manage version updates can result in inconsistent datasets, delayed submissions, and inspection findings. Thus, implementing structured processes for MedDRA updates is essential for regulatory compliance and pharmacovigilance.

Impact of Version Updates on Clinical Trials

Each MedDRA update can affect ongoing trials in several ways:

• New terms: Coders gain access to updated LLTs and PTs reflecting current medical knowledge.
• Retired terms: Certain LLTs may be deprecated, requiring recoding of existing events.
• Hierarchical shifts: PTs may be reassigned to different SOCs, changing how aggregate analyses are performed.
• Cross-study comparisons: Trials coded with different versions may produce inconsistent datasets unless reconciled.

For example, if “Myocardial infarction type 2” is added as a PT in a new version, coders must reassign prior cases coded under general “Myocardial infarction” PTs to ensure consistency in safety analyses.

Version changes may also impact DSURs, PSURs, and aggregate reports. Regulators often question whether sponsors have adequately managed version transitions when inconsistencies appear in safety datasets.

Case Example: MedDRA Version Transition in an Oncology Trial

Consider a Phase III oncology trial using MedDRA version 23.0. Midway through the trial, version 24.0 introduces new PTs for immune-related adverse events, including “Immune checkpoint inhibitor colitis.” The sponsor must:

1. Update the safety database to MedDRA v24.0.
2. Recode historical events from general terms like “Colitis” to the new PT where appropriate.
3. Train coders on the new version and updated coding conventions.
4. Document the reconciliation process in the Trial Master File (TMF).

This case illustrates how timely adoption of new versions ensures accurate pharmacovigilance and regulatory compliance, particularly in emerging therapeutic areas.

Regulatory Expectations on MedDRA Version Management

Regulatory agencies expect sponsors to demonstrate traceability and consistency in handling MedDRA updates. Common expectations include:

• Version documentation: Submissions must clearly state the MedDRA version used for coding.
• Transition management: Sponsors should document how and when version updates were implemented.
• Reconciliation: Safety datasets must be reconciled to avoid inconsistencies across versions.
• Training: Coders must be trained on new terms, structures, and conventions introduced in each update.
• Audit readiness: Regulators may review version transition logs during inspections.

Inspection findings often highlight failures in version management, such as continued use of outdated versions or lack of documentation on recoding decisions. For global compliance, sponsors should align coding practices across all regions, ensuring FDA, EMA, and CDSCO submissions use harmonized MedDRA versions.

Best Practices for Handling Version Updates

To effectively manage MedDRA updates, sponsors should adopt the following practices:

• Establish SOPs: Define clear procedures for adopting new MedDRA versions.
• Plan updates: Implement updates immediately after March and September releases.
• Reconcile datasets: Perform systematic recoding of historical cases impacted by new or retired terms.
• Train coders: Provide refresher training with examples of new terms and hierarchical changes.
• Audit processes: Maintain version control logs, reconciliation records, and coding decision documentation.

For instance, a sponsor may maintain a version reconciliation log that documents all PTs changed during an upgrade, along with rationale for recoding decisions. Such logs serve as valuable inspection artifacts.

Challenges in Managing Updates

Despite best practices, challenges remain:

• Resource burden: Updating databases and training coders requires time and staff.
• Cross-study consistency: Reconciling coding across multiple ongoing trials can be complex.
• Regulatory timelines: Version updates often coincide with critical submission deadlines.
• Automation risks: Auto-recoding features may misclassify terms without manual review.

These challenges highlight the importance of proactive planning, sponsor oversight, and hybrid manual/automated reconciliation processes.

External Resources and References

Coders and safety professionals should leverage external resources to stay aligned with regulatory expectations. The ISRCTN Registry often references MedDRA coding standards in trial protocols, demonstrating global alignment on terminology usage.

Key Takeaways

Handling MedDRA version updates is a critical pharmacovigilance function. Clinical teams must:

• Adopt new MedDRA versions promptly after release.
• Reconcile coding across trials to maintain consistency.
• Document transitions, rationale, and recoding decisions in audit-ready logs.
• Train coders on new terms and hierarchical changes.
• Maintain inspection readiness by aligning global submissions to the same version.

By managing MedDRA updates systematically, sponsors ensure accurate safety data, regulatory compliance, and reliable pharmacovigilance across global clinical development programs.

Understanding MedDRA and Its Importance in Clinical Trials

Introduction to MedDRA

The Medical Dictionary for Regulatory Activities (MedDRA) is an internationally standardized medical terminology developed under the auspices of the International Council for Harmonisation (ICH). It is the global standard for coding adverse events, medical histories, indications, and procedures across clinical trials and post-marketing surveillance. Regulators such as the FDA, EMA, MHRA, PMDA, and CDSCO require the use of MedDRA for consistent reporting of adverse events.

MedDRA provides a common language that allows harmonized reporting of clinical and safety data across companies, regions, and regulatory submissions. This prevents misinterpretations that could arise if sponsors used different medical terminologies. For example, one sponsor might describe an event as “heart attack,” while another uses “myocardial infarction.” MedDRA coding ensures both are standardized under the same Preferred Term (PT) for regulatory analysis.

The dictionary is used throughout the product lifecycle: from early phase clinical trials to post-marketing pharmacovigilance. In safety reporting databases such as the FDA FAERS and the EMA EudraVigilance, MedDRA ensures that safety signals are consistently captured and analyzed across millions of case reports.

Why MedDRA Is Used in Clinical Trials

MedDRA is not just a vocabulary; it is a regulatory requirement and an analytical tool. Its use offers several key benefits:

• Regulatory compliance: All IND, NDA, BLA, and CTA submissions must use MedDRA coding for adverse events.
• Consistency: Ensures uniform representation of medical concepts across trials, preventing duplication or misclassification.
• Signal detection: Facilitates statistical analyses to identify potential safety issues across large datasets.
• Global harmonization: Enables cross-regional reporting under FDA, EMA, and WHO guidelines.
• Audit readiness: Provides clear documentation and coding traceability during GCP and pharmacovigilance inspections.

For example, in oncology trials, adverse events such as “low white blood cell count” are coded under the MedDRA PT “Neutropenia.” This standardization enables consistent analysis of hematological toxicity across multiple compounds and studies.

Structure of MedDRA and Its Application

MedDRA is hierarchical, consisting of five levels:

1. Lowest Level Terms (LLTs): Lay or specific terms entered by investigators (e.g., “heart attack”).
2. Preferred Terms (PTs): Standardized terms for analysis (e.g., “Myocardial infarction”).
3. High Level Terms (HLTs): Group of related PTs (e.g., “Ischemic coronary artery disorders”).
4. High Level Group Terms (HLGTs): Broader groupings (e.g., “Coronary artery disorders”).
5. System Organ Class (SOC): Highest level, grouping by organ system (e.g., “Cardiac disorders”).

By applying this structure, sponsors ensure that adverse events can be reviewed both in detail (PT-level) and broadly (SOC-level). Regulatory reviewers use SOC-level summaries to evaluate system-wide toxicities, while safety physicians use PT-level data for case-level assessments.

A sample MedDRA coding workflow might look like this:

This process demonstrates how MedDRA transforms site-reported terms into standardized codes for regulatory use.

Challenges and Limitations of MedDRA Use

While MedDRA brings enormous benefits, it is not without challenges:

• Ambiguous terms: Investigators may use vague language like “unwell,” which requires careful coding to avoid misclassification.
• Version updates: MedDRA is updated biannually (March and September). Sponsors must reconcile coding across versions, which can affect ongoing trials.
• Training needs: CRAs, coders, and safety teams must be trained regularly on MedDRA use and version changes.
• Auto-coding risks: Automated systems can misclassify terms if not reviewed by trained coders, especially for complex events.
• Consistency across teams: Large sponsors with multiple coding teams must maintain coding conventions to avoid discrepancies.

For example, if one coder selects the PT “Headache” for the term “Migraine” while another selects “Migraine,” analyses of central nervous system toxicity could be distorted. SOPs and coding guidelines are critical to mitigate such risks.

Regulatory Expectations and Inspections

Regulatory authorities expect sponsors to demonstrate traceability in MedDRA coding. During inspections, common findings include:

• Incorrect coding of investigator-reported terms.
• Lack of documentation explaining coding choices.
• Failure to update coding after MedDRA version upgrades.
• Inconsistent coding across related studies.

To prepare, sponsors should maintain coding conventions documents, perform regular coding reviews, and reconcile data after each MedDRA update. Training logs for CRAs and coders are often reviewed by inspectors as proof of competency.

Best Practices for MedDRA Implementation

To maximize the benefits of MedDRA and ensure regulatory compliance, clinical teams should adopt these best practices:

• Establish clear SOPs for coding workflows and version updates.
• Use hybrid coding: auto-coding for straightforward terms, manual coding for complex/ambiguous cases.
• Conduct regular coding consistency checks and audits.
• Train CRAs, coders, and pharmacovigilance staff on MedDRA fundamentals and updates.
• Reconcile coded data across studies and ensure alignment in DSURs and PSURs.

For example, a sponsor may implement quarterly coding review boards to evaluate difficult terms and ensure consistent PT selection across all trials.

External resources such as the WHO International Clinical Trials Registry provide references to safety reporting standards, reinforcing the need for harmonized MedDRA use worldwide.

Key Takeaways

MedDRA is the global standard for adverse event coding and is indispensable for regulatory compliance, data integrity, and safety signal detection. Clinical teams must:

• Understand the hierarchical structure of MedDRA (LLT → PT → HLT → HLGT → SOC).
• Apply consistent coding practices to avoid misclassification.
• Ensure timely updates with each new MedDRA version release.
• Train staff regularly to maintain competency in coding practices.
• Maintain audit-ready documentation and coding conventions.

By implementing robust MedDRA processes, sponsors and CROs ensure that safety data is reliable, regulators receive accurate submissions, and patient safety remains at the core of clinical research.