MHRA Updates Guidance on Non-Investigational Medicinal Products in Clinical Trials

10th October 2025

MHRA Updates Guidance on Non-Investigational Medicinal Products in Clinical Trials

Summary: The Medicines and Healthcare products Regulatory Agency (MHRA) has published revised guidance on the use of non-investigational medicinal products (NIMPs) in clinical trials, effective from 28th April 2026. This updated guidance provides clarity on the regulatory requirements for NIMPs, which are medicinal products used in clinical trials but not as investigational medicinal products (IMPs). Key points include:

• Definition of NIMPs: A NIMP is a medicinal product used or to be used in a clinical trial, as described in the protocol, but not as an IMP.

• Authorisation Requirements: In most cases, NIMPs used in a clinical trial should hold a marketing authorisation. Where an authorised NIMP does not exist or where the sponsor cannot be reasonably expected to use it, the sponsor may use an unauthorised NIMP, ensuring that clear justification for this is given in the trial protocol.

• Examples of NIMPs:

  • Rescue Medications: Medicinal products identified in the protocol as those that may be administered to patients when the IMP does not have satisfactory efficacy or when the effect of the IMP is too great and is likely to cause an adverse reaction.

  • Challenge Agents: Medicinal products given to trial participants to produce a physiological response that is necessary before the pharmacological action of the IMP can be assessed.

  • NIMPs Used to Assess Endpoints: Medicinal products given to a trial participant as a tool to assess a relevant clinical trial endpoint.

  • Background Treatment: Medicinal products administered to each of the clinical trial participants, regardless of randomisation group, either to treat the indication which is the object of the study or as part of the standard of care treatment for a condition which is not the indication under investigation but is relevant for the clinical trial design.

• Documentation and Labelling: Sponsors must ensure that appropriate documentation is maintained for all NIMPs used in the trial, including details of manufacture and control. NIMPs must be labelled in accordance with the requirements set out in the guidance.

• Safety Reporting: Adverse events related to NIMPs must be reported in accordance with the safety reporting requirements outlined in the guidance.

This updated guidance aims to ensure that NIMPs used in clinical trials are appropriately authorised, documented, and monitored, thereby supporting the safe and effective conduct of clinical trials.

Link: Clinical Trials for Medicines: Non-Investigational Medicinal Products

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