Key Insights: Advanced Therapy Medicinal Products (ATMP) guidance development

Published 13 July 2026

In this month’s Key Insights, we explore the British Pharmacopoeia's (BP) developments in Advanced Therapy Medicinal Products (ATMP).

We will cover: 

  • the BP's advisory role in supporting ATMP development
  • new guidance on replication competent virus (RCV) testing and genomic titre/vector copy number measurement
  • stakeholder consultations on AAV empty capsids and what they mean for the field
  • key analytical and quality challenges the BP is working to address in ATMP development
  • how to contribute to shaping future BP guidance and standards

The BP's approach to ATMP guidance

As a rapidly evolving field, Advanced Therapy Medicinal Products (ATMP) development often extends beyond the scope of established pharmacopoeial standards. The BP ATMP guidance has therefore been developed as an advisory resource, offering expert recommendations, examples and points for consideration, rather than setting mandatory requirements. 

This approach complements existing standards and regulatory frameworks while providing the flexibility needed to support innovation. The BP continues to play a leading role in supporting the development and quality control of ATMPs. As these innovative medicines move from research into clinical use, the BP aims to provide high quality guidance, to support their development and use.

You can view and download the guidance on the Advanced Therapy Medicinal Products Guidance page of the BP website.

Recent publications and stakeholder consultations

Two key milestones in this work are:

A replication-competent virus is a virus that can reproduce itself; in gene therapy, viral vectors are designed not to do this, so manufacturers test for any replication-competent contaminants that may have been accidentally created during production. 

This RCV guidance provides a framework for the detection and control of replication competent viruses across commonly used vector systems, including adeno-associated virus (AAV) and lentiviral vectors. It supports manufacturers and developers by outlining considerations for sampling strategies, method validation, and the selection of appropriate analytical approaches, reflecting the increasing complexity of viral vector-based therapies.

Genomic titre is a measure of how many viral particles containing genetic material are present in a sample, and vector copy number indicates how many copies of the therapeutic gene are inside each cell.

Alongside this, the BP has demonstrated engagement with stakeholders through successful public consultations on follow up parts to the already published characterisation of the capsid particle population for AAV products guidance. These consultations, covering, Encapsidated DNA Characterisation, and Capsid Protein Characterisation, have both provided valuable opportunities for industry, NHS and academia to contribute to evolving guidance. 

Recent expert discussions have focussed on resolving over 200 technical comments from 13 responders and refining the guidance’s to ensure it is both scientifically robust and practically applicable, before publication, later this year.

These activities reflect the BP’s commitment to addressing key analytical and quality challenges associated with ATMPs, particularly in areas such as:

  • characterisation of vector-related impurities (e.g. empty versus full capsids)
  • advanced molecular and sequencing approaches for product characterisation
  • ensuring safety through improved detection of replication-competent viruses

Shaping the future of ATMP standards

More broadly, BP ATMP work continues to evolve in response to emerging technologies and stakeholder needs. Stakeholder input remains central to this work, and the BP encourages continued engagement from across the ATMP community to help shape future guidance and standards.

If there are areas of ATMP development where you or your organisation would benefit from new or enhanced British Pharmacopoeia guidance, particularly at the forefront of emerging technologies and best practice, please do get in touch. 

We welcome input from across the community to help shape future standards. You can contact us at biolstandards@mhra.gov.uk.