Clinical Research: Phase 1 - Phase 4

Biomarker Method Validation in Rare Disease Drug Development

While drug discovery has seen major advances over the last few years — especially in the domain of rare disease research — the number of new drug approvals has not kept pace with increasing development costs. However, the innovative use of biomarkers has the potential to change that trend.

Biomarkers in Rare Disease Research

Biomarkers are objectively measurable characteristics that can be used as indicators of normal biological processes, pathological processes or physiologic responses to a drug or other intervention. Some familiar biomarkers include blood pressure and lipid profiles.

Biomarkers offer rare disease drug developers some distinct advantages in cutting costs while engaging in rigorous research:

  • Biomarkers can serve as surrogate endpoints. Not having to depend on clinical endpoints significantly shortens study length.
  • They reduce the samples size necessary for statistical significance. Rare disease research is often hindered by a lack of available patients.
  • Patients likely to respond to a drug can be more easily identified.
  • The concrete, objective nature of biomarkers reduces uncertainty in regulatory decisions.

Challenges of Biomarker Method Validation

For biomarkers to be useful, researchers must understand exactly what is being measured and its biological relevance. Unfortunately, biomarkers and their measurement methods can be challenging to validate.

The following must be addressed before a biomarker can be integrated into study design:

  • Establishing normal ranges. Most biomarkers are found within the general population with presentations varying by a host of factors, including gender and age. For example, hemoglobin levels that are normal for a woman can indicate anemia in a man.
  • Quantifying and interpreting biomarkers. These characteristics can be heterogeneous between patients with the same condition and may possess significant chemical diversity within classes of compounds.
  • Ensuring measurement methods are robust enough for regulatory approval. All methods must conform to a high standard of scientific rigor.

Fit-for-Purpose Method Validation

We’ve found that a fit-for-purpose approach to biomarker method validation is crucial for its success. This means that assay validation for drug development should be tailored to meet the intended purpose of the biomarker study.

This includes careful planning, design and vetting with regulatory agencies through the following steps:

1. Establish assay acceptance criteria.

Any acceptance criteria must be determined based on:

  • The predefined needs of the study rather than the capabilities of the assay itself.
  • The nature of the assay methodology and data generated using that assay.
  • The variability of the biomarker within and between study populations.

2. Develop a biomarker work plan.

Before assay development can commence, the study objectives, intended use of assay data, and level of data documentation all must be carefully defined.

3. Create standardized procedures for sample collection and handling.

In clinical research, sample integrity must be maintained from collection through analysis. This requires well-defined protocols that take into account short-term, long-term, freeze/thaw and bench-top stability.

4. Perform method validation.

This final step is an iterative fit-for-purpose process in and of itself that goes through multiple phases. Continuous reassessment of data and optimization of the assay method is key.

Once sufficiently validated, biomarker measurement and evaluation methods can be used with confidence by rare disease researchers and drug developers. Read our white paper,

Read our white paper, Fit-For-Purpose: A Strategic Approach to Biomarker Method Validation for Rare Disease, for the full story.