The UK Medicines and Healthcare products Regulatory Agency (MHRA) has opened a consultation on a draft regulatory framework for rare disease therapies, addressing the evidentiary problem created by very small patient populations, limited natural history data and heterogeneous disease biology.
The consultation, published on 21 May 2026, follows MHRA’s earlier commitment to develop a bespoke rare disease pathway. It gives the proposal a more defined structure and invites comments before 30 July 2026.
MHRA’s starting point is that conventional development may not work well for some rare disease therapies. Randomised controlled trials may be impractical, clinically meaningful endpoints may take years to observe, and the evidence base may remain uncertain at the point when patients and clinicians seek access. The draft framework is intended to create a regulated route through that uncertainty, rather than requiring all evidence questions to be resolved before any authorised use.
The proposed mechanism is an Investigational Marketing Authorisation (IMA). MHRA describes this as a single authorisation combining clinical-trial permission with a continuously reviewed marketing authorisation. It would allow controlled early access where the available evidence supports a positive benefit-risk judgement, while further clinical and real-world data continue to be collected.
The framework is aimed at rare disease therapies typically affecting around 1 in 50,000 people or fewer in the UK, a prevalence which aligns with NICE’s ultra-rare disease definition. MHRA also points to individualised therapies and other products where small numbers, variable disease course or long-term follow-up requirements make conventional evidence generation difficult.
The draft proposal comments on the link between the regulatory route and reimbursement and commissioning. An IMA would not itself guarantee funding, but may support initial reimbursement consideration where evidence is still developing. The proposal encourages early engagement with NICE and NHS England and discusses managed access, conditional reimbursement and periodic review as possible ways to handle residual uncertainty.
The caveat is that the route depends on wider system capacity. MHRA identifies national data infrastructure, disease registries, four-nation coordination and managed-access capability as practical requirements. Without those elements, an investigational authorisation could create regulatory permission without a workable access pathway.
The proposal therefore sets out a more integrated model for selected rare disease therapies. Licensing flexibility, HTA assessment, commissioning decisions and post-authorisation evidence generation would need to operate as linked parts of the same lifecycle, rather than as sequential steps.
Source: Medicines and Healthcare products Regulatory Agency
Link: Draft rare disease therapies regulatory framework
Date: 21 May 2026
