OBJECTIVES : Many oncology drugs contain in their drug label the requirement to test for specific biomarkers prior to administration. This requirement sometimes relates to the mechanism of action of the drug, which interacts directly or indirectly with a certain biomarker. This is also known under the concept of a treatment-by-biomarker interaction. The presence (or absence) of a biomarker is thus deemed crucial for the effectiveness of the drug in the patient. With this research, we wish to examine the available evidence for this treatment-by-biomarker interaction and by consequence, the requirement to test for this specific biomarker as stated in the European Medicine Agency’s (EMA) drug labels for oncology drugs.

METHODS : We searched the Pharmkgb drug annotation database to identify approved oncological drugs with the requirement to test for specific biomarkers due to a treatment-by-biomarker interaction claim. Public assessment reports of the EMA were then consulted to identify available clinical trials, which support the interaction claim.

RESULTS : We identified five oncological drugs, which obtained information to assess the treatment-by-biomarker interaction. In total, 12 clinical trials were analysed of which six trials obtained significant (p ≤ 0.05) results to support the treatment-by-biomarker interaction.

CONCLUSIONS : The EMA drug label specifies for some oncology drugs the requirement to test for specific biomarkers. This requirement sometimes relates to a treatment-by-biomarker interaction. The evidence to prove the existence of this interaction was examined in this research. We could only identify 12 randomized clinical trials, which were accordingly designed to prove this interaction, of which six obtained significant results. The treatment-by-biomarker interaction claim in the majority of oncology drugs approved by EMA is established via the mechanism of action of the drug reasoning rather than by randomized clinical trial evidence.