UK medicines regulator consults on a tailored regulatory framework for rare disease therapies

The MHRA has launched a public consultation on a proposed Rare Disease Therapies Regulatory Framework, marking a significant shift in how therapies for very rare conditions will be developed and authorised in the UK.

The consultation, published on 21 May 2026, is open until 30 July 2026, and is particularly relevant for pharmaceutical companies, biotech developers and other stakeholders involved in rare disease innovation.

The challenges for rare disease medicine development

Rare diseases affect more than 3.5 million people in the UK, yet only a small proportion currently have an approved treatment, with the current system not well tailored to enable appropriate medicines to be developed. 

The MHRA recognises that traditional regulatory pathways are often not workable in this space due to specific challenges:

• very small and heterogeneous patient populations
• limited natural history data
• the practical difficulty of conducting standard randomised controlled trials. 

The proposed framework is intended to address these barriers and enable earlier access to promising therapies.

A new “Investigational Marketing Authorisation” pathway

At the centre of the proposal is a new, flexible route to authorisation: the Investigational Marketing Authorisation (IMA).

Features of the IMA include:

• being technology agnostic, to include innovative cell and gene therapies as well as repurposed established medicines
• combining clinical trial approval with a staged pathway towards marketing authorisation
• allowing earlier, controlled patient access while further evidence is generated
• supporting the use of adaptive trial designs and real world data in evidencing safety and efficacy. 

For developers, this represents a move towards a more iterative, lifecycle-based regulatory model, rather than the usual sequential process. The MHRA will require clinical trials to meet ICH requirements, so that the data collected can support the approval of new therapies internationally.

The existing incentives available for tackling rare disease through orphan designation would be available for appropriate medicines alongside the IMA.

Greater flexibility – while maintaining regulatory scrutiny

While the framework introduces greater flexibility, the MHRA is clear that standards of safety, quality and efficacy will not be reduced. 
Instead, the approach is intended to be risk-proportionate, recognising the realities of rare disease development while maintaining robust oversight.

Notably, the proposals also place significant emphasis on:

• ongoing patient engagement and informed consent; and
• clear communication of uncertainty and benefit–risk to patients and families. 

Why manufacturers should engage

The consultation is explicitly aimed at ensuring the proposed system is workable in practice, and the MHRA is calling for input from industry on key areas such as:

• eligibility criteria for the new pathway
• evidence expectations (including real world data)
• interaction with existing routes (for example, orphan designation and ILAP)
• the practical operation of the staged authorisation model. 

For manufacturers, this is an opportunity to help shape a framework that could materially affect development timelines, evidence-gathering strategies and market access for rare disease products. 

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