Treatment adherence to oral chemotherapy in patients with locally advanced or metastatic non- small cell lung cancer: Protocol for a hospital pharmacy-based real-world study.

Objective: This article describes a study protocol for evaluating adherence to oral chemotherapy (OCT) in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) in Spain.

Methods: This multicenter, observational, prospective study will be conducted by six hospital pharmacists from six Spanish hospitals. The study will include men and women aged 18 years or older with a diagnosis of locally advanced or metastatic NSCLC who are being treated or have been prescribed OCT. Once included, the patient will be active and prospectively followed up for 3 months, including four study visits to record information on sociodemographic variables, antineoplastic treatment and adherence, pharmaceutical care, clinical variables, and patient-reported outcomes (PRO) (the 3-level version of EQ-5D, the EORTC Core Quality of Life Questionnaire, the Brief Illness Perception Questionnaire, the Treatment Satisfaction with Medicines Questionnaire, and the PRO version of Common Terminology Criteria for Adverse Events). Twelve months after patient inclusion, we will record information on the disease progression status and dispensed prescriptions. The primary outcome is the percentage of treatment adherence that will be calculated based on the pill count as follows: the difference between the number of pills dispensed minus the number of unused pills will be divided by the number of days of treatment multiplied by the number of pills/day prescribed by the oncologist; this quotient will be multiplied by 100 to obtain the percentage of adherence. Based on the that pill count reconciliation, those with a percentage adherence greater than80% will be primarily categorized as adherent. Secondarily, treatment adherence will be also calculated based on the proportion of days covered and the 4-items Morisky Green Levine Medication Adherence Scale. To analyze the impact of patients' and treatment characteristics on adherence, bivariate analyses will be performed using different adherence cut-off points. To evaluate the impact of adherence on treatment efficacy as evaluated by progression-free survival, we will be using the Kaplan-Meier method and compare it with the log-rank test and univariate Cox regression analysis.

Conclusions: We expect that our study will provide initial information on key aspects of adherence to OCT (measurement, facilitators, and barriers) and its relationship with patients' and clinically relevant outcomes in the setting of NSCLC, and that this information will help in designing pharmaceutical interventions to improve adherence.