In pharmacovigilance, consistency isn’t a luxury – it’s a necessity.

But when it comes to safety labelling, there’s been a gap between inclusion and understanding.

Whilst we all use MedDRA terminology, there hasn’t been a single, agreed way to present adverse reactions in product labelling such as the SmPC. Every company has, in effect, developed its own system for grouping related MedDRA terms – which means similar safety information can look very different from one product to the next even within the same Class of Products.

Recognising this issue, CIOMS has developed a new concept: MedDRA Labelling Groupings (MLGs).

Why MLGs matter

For years, Standardised MedDRA Queries (SMQs) have been the backbone of signal detection. They help identify potential safety signals by grouping similar medical terms into a single concept term – but they weren’t built for communicating those findings consistently into labelling.

MLGs aim to close that communication gap.

They provide a structured, harmonised way to group near-synonymous MedDRA Preferred Terms (PTs) that describe the same clinical concept when used in product labelling.

In simple terms, MLGs move Pharmacovigilance/Regulatory from how safety issues are detected to how they are described – ensuring consistency and clarity across companies, products, and regulatory submissions.

What’s in the CIOMS 2024 report

The CIOMS working group, active since 2019, recently published its guidance:

Introduction to MedDRA Labeling Groupings (MLG): A Standardized Approach to Grouping Adverse Reactions in Product Safety Labels.

Source: CIOMS Publications

Some key takeaways:

• Purpose: To create a shared convention for grouping related MedDRA terms in safety labelling.
• Principles: Combine PTs that mean essentially the same thing into one MLG.
• Example: Terms such as Abdominal pain, Abdominal discomfort, and Abdominal tenderness could be presented under one umbrella term, with a supporting footnote listing the underlying PTs.
• Status: MLGs are not yet created centrally. Rather the CIOMS Working Group has created principles and conventions for the development of MLGs. An owner & developer is needed to bring forward the production of MLGs and to maintain them.
• Maintenance: Once in place, MLGs should be reviewed regularly (every six months) to stay aligned with the latest MedDRA version.
• Regulatory impact: The MLG framework doesn’t change legislation – it simply aims to make labelling more consistent and transparent.

What this means for pharmacovigilance and regulatory teams

For safety and regulatory professionals, the introduction of MLGs represents a meaningful step forward.

By adopting this approach, companies could:

• Improve clarity and comparability across product labels
• Reduce ambiguity in how similar reactions are described
• Provide clearer, more practical safety information for clinicians and patients
• Strengthen alignment between pharmacovigilance outputs and labelling communication

It’s a pragmatic development that supports better science and better communication – without creating unnecessary complexity.

PharSafer’s perspective

At PharSafer®, we see the introduction of MLGs as a welcome evolution in how pharmacovigilance information is shared providing a more coherent approach to labelling.

With over two decades of experience supporting global clients across both pre- and post-marketing safety, PharSafer understand the importance of clear, compliant, and consistent communication – and how initiatives like this can help the industry speak a more unified language.

Looking ahead

The CIOMS MLG framework signals a move toward greater harmonisation in safety communication – one that will take collaboration, consistency, and continued interpretation across the industry.

Looking to strengthen your own labelling or safety framework?

Partner with PharSafer® – specialists in global pharmacovigilance, regulatory intelligence, and safety strategy.

📩 Get in touch to learn how to align your labelling and safety systems with evolving international standards and best practices: https://pharsafer.com/contact-us/

If you have any questions or require further guidance, please contact us directly: enquiries@pharsafer.com 📧

Brought to you by the PharSafer Global Regulatory Intelligence Group.