Determining the Need for a Companion Diagnostic (CDx) in Precision Medicine Clinical Trials

Precision Medicine Clinical Trials - Companion Diagnostic Determination

In drug development, especially with the rise of precision therapies, determining whether you need  a Companion Diagnostic (CDx) is crucial. As therapies become more tailored, the role of CDx becomes essential for identifying the right patients, improving treatment efficacy, and mitigating adverse reactions. The decision to develop and implement a CDx involves not only understanding the technical and regulatory complexities but also evaluating whether your organization has the resources and expertise to handle the challenges.

Companion Diagnostic in Precision Medicine Clinical Trials

This blog outlines key considerations for determining whether your assay qualifies as a CDx and conducting a CDx clinical study. It highlights critical questions sponsors should ask regarding large financial cost and impact, regulatory strategies, clinical operations, and quality management systems (QMS) alignment. These insights help assess whether your organisation has the resource and expertise to conduct a CDx clinical study ensuring success in the highly regulated and intricate landscape of drug development.

Rapid progress in precision therapies introduces many challenges for Pharma Sponsors in their drug development programmes. The need to develop a Companion Diagnostic (CDx) brings an additional burden, particularly since In Vitro Diagnostic (IVD) and Companion Diagnostic (CDx) development may not be a core competency of most pharma organisations. An understanding of the regulatory and clinical compliance landscape is essential for pharma sponsors implementing CDx in their clinical trials. Increasingly, pharma are also taking on the responsibility of sponsoring CDx studies in parallel to their early phase clinical trials.

Is my assay a Companion Diagnostic (CDx)?

An assay is considered a CDx if it is essential for the safe and effective use of a corresponding medicinal product. This includes identifying patients who may benefit from the drug, or be at risk of serious side effects. In some jurisdictions (e.g. US), CDx may also be used to monitor the response to treatment for the purpose of adjusting the treatment to achieve improved efficacy or safety.

Our assay is a Companion Diagnostic (CDx), what next?

Prior to planning CDx development, Sponsors should consider their bandwidth for development by considering the following questions:

• Do we have sufficient funds to support a CDx development?

To develop a CDx assay might involve a high financial cost that could have a high impact on an organisation. This might not always possible for some smaller sponsors.

• Do we understand the regulatory requirements for using a CDx in a precision medicine clinical trial in our countries of interest?

It is important to recognise that the regulatory requirements for using a CDx to enrol patients in a clinical trial vary from one country to another. For example, in the United States (US), the Investigational Device Exemption (IDE; 21 CFR 812) governs the use of 'Investigational Use Only' devices including within clinical trials of medicinal products. In the European Union (EU), IVDR has increased the regulatory burden for testing EU samples with specific pathways for CDx studies. In addition to this, implementation of IVDR performance study requirements can also vary between the different EU countries.

• Do we have the clinical operations processes to support CDx clinical investigations/performance studies?

There are a number of key criteria and responsibilities that a CDx study sponsor must consider, including site qualification and selection, regulatory and ethics approvals, monitoring of testing sites, safety reporting, and study reporting. It is expected that CDx study Sponsors have adequate processes in place to conduct the study in compliance with Good Clinical Practice (e.g. ISO 20916).

• Examples of other questions to consider in precision medicine clinical trials:

• Do we need to amend the scope of our quality management systems (QMS) ? and
• How do we identify the gaps?
• If certified, do we need to inform the accreditation body and work through the process for an updated certificate?

It is important that, if a Pharma Sponsor implementing a CDx in their drug Clinical Trial, is unsure of any answers to these key questions that they seek external support from a specialist team of regulatory and clinical experts who have successfully delivered a number of CDx development projects.

Download our more comprehensive whitepaper – “Implementing a CDx in your Drug Development Programme”

ARC Regulatory  offers full regulatory, clinical and pharma sponsor delegation services for IVD and CDx Studies. Find out more about our IVD/CDx Clinical Study Sponsor Delegation Service Package