OBJECTIVES: To analyze which factors may contribute to the efficacy-effectiveness gap in oncology drugs in which lower effectiveness, in clinical practice, was observed when compared with efficacy in their respective clinical trials (CTs).

METHODS: We conducted a retrospective observational study. We reviewed medical records of patients treated in a university hospital with aflibercept, cabazitaxel, pazopanib, pertuzumab and plerixafor (in which a lower effectiveness vs efficacy was identified) from inclusion in the hospital. Collected variables included patient characteristics and one outcome variable per drug (overall survival for aflibercept, cabazitaxel and pazopanib; progression-free survival for pertuzumab; >5x10 CD34+ cells in <4 apheresis days for plerixafor in Non Hodgkin lymphoma (NHL); and >6x10 CD34+ cells in <2 apheresis days for plerixafor in multiple myeloma (MM)). Outcomes and patients’ characteristics were compared to those of patients in CTs.

RESULTS: Data of 60 patients were analyzed: 11 received aflibercept, 12 cabazitaxel, 13 pazopanib, 8 pertuzumab, 8 plerixafor for NHL, and 8 plerixafor for MM. Effectiveness was between 10% and 80% lower (median 52%) than efficacy in CTs. Our patients presented worse ECOG performance status than those included in CTs. Those treated with aflibercept received also different chemotherapy regimens, those that received cabazitaxel had more frequently metastasis and higher basal prostatic specific antigen values. Patients treated with pazopanib, pertuzumab or plerixafor received different previous therapies compared to those in CTs.

CONCLUSIONS: Worse ECOG performance status of patients can contribute to worse outcomes with aflibercept, cabazitaxel, pazopanib and pertuzumab in real world. Concomitant treatments, previous therapies or metastasis could also contribute to the effectiveness-efficacy gap. More severe patients than those included in clinical trials are frequently treated in clinical practice, this factor can contribute to worse effectiveness results than efficacy in clinical trials. Effectiveness has to be measured and considered when selecting treatments.