Background and importance Over the last decade the number of clinical trials (CTs) has increased exponentially worldwide as well as their complexity.
The identification of possible interactions of the concomitant medication with the investigational drug is a key point to avoid bias in the study result, and to ensure patient safety.
The pharmacist, as a member of the investigational team, may also be involved in screening/randomisation of the subjects.
Aim and objectives To review the concomitant medication of patients who are candidates to start a CT in order to detect possible interactions.
Material and methods Descriptive study carried out in a tertiary university hospital over a 1-year period (September 2020–August 2021). All patients who were candidates to participate in an onco-haematology clinical trial that included an oral investigational drug were included. Information on pharmacological treatment was obtained through a clinical interview conducted in the pharmaceutical care consultation or by telephone. The inclusion/exclusion criteria relating to concomitant prohibited/authorised medication described in the protocol of each trial were applied.
We retrospectively collected: sex, diagnosis, concomitant medication, pharmaceutical interventions, type of intervention, how many of these were taking alternative medicine products, and number of screening failures.
Results A total of 410 patients (53.90% women) were interviewed. According to the diagnosis, 17.32% of the patients had lung cancer, 16.83% genitourinary, 16.10% neuroendocrine tumours, 14.88% breast cancer, 8.78% haematological tumours and 26.09% others. A total of 2262 drugs were reconciled, the median of which they took per patient (range) was 5 (0–16). Interventions were performed in 155/410 (37.80%) patients. Most of these (69.03%) were for suspension of treatment not authorised by protocol. 26.10% of the patients were taking alternative therapy at the time of screening. Finally, 20.49% were screening failures.
Conclusion and relevance The results of our study show that approximately 4 in 10 patients require at least one change in their usual treatment.
The involvement of the pharmacist in the assessment of interactions may play a central role in the research process, which can directly influence the inclusion of a patient in a clinical trial.
Conflict of interest No conflict of interest