5. Clinical Trial Design

Many medicinal product candidates fail at each development phase and will not be taken further. Biomarkers, including genomic biomarkers (DNA and RNA measurements), should reduce this failure rate.

The most common reason for using genomic biomarkers in clinical trials is to improve patient selection. That is, only patients with certain DNA and/or RNA variations will be able to take part. The table below lists common methods for selecting patients for clinical trials using DNA and/or RNA variation, with examples.

Selection method


Exclude patients likely to have an adverse reaction .

Exclude HIV  patients who are at risk  of an allergic reaction because of the HLA-B*5701  genetic variant .

Select patients who are likely to respond (also avoid exposing other patients to a new medicine who are unlikely to benefit ).

Select melanoma patients with ‘BRAF ’ mutations for trials involving medicines called ‘kinase inhibitors’.

Select patients who have a particular disease sub-type (or severity) of interest in the trial.

Select patients with breast cancers that over-express the Her2/neu protein.