What Does Real World Evidence Tells? A Case Analysis in Breast Cancer Using Pharmaceutical Consultation Data

OBJECTIVES: Real World Evidence (RWE) use in both safety and effectiveness evaluations is recognized by EMA and FDA. There is extensive evidence of RWE use in oncology, but studies focused on Pharmaceutical Consultation (PC) and breast cancer (BC) are lacking. CDK4/6 inhibitors are novel oral agents in hormone receptor-positive metastatic breast cancer (MBC). The objective of this study was to evaluate RWE of these agents in MBC using PC data.

METHODS: This retrospective observational study included patients followed in PC between 2017 and 2021. Data were collected from the electronic health records (ERH) and from the structured PC database. Baseline demographic variables, histopathological variables and previous therapies were collected. The main clinical outcomes were Progression-Free Survival (PFS) and treatment tolerability. The analysis of possible confounding factors was performed with Chi-Square test for categorical variables and T-student test for continuous numerical variables, with subsequent multivariate analysis. Statistical analysis was done with Python 3.8.8.

RESULTS: The study included 32 patients with MBC (median age 68y; all-female; median time from diagnosis of 6 years), 13 treated with Palbociclib, 15 with Ribociclib and 4 with Abemaciclib. Majority of patients presented G2 Tumors (43.8%, p=0.69), BIRADS 2 at diagnosis (43.8%, p=0.27) and ECOG PS 0-1 (87.3%, p = 0.26). Estrogen receptors were positive in 93.6% of patients (p=0.34) and Ki67 were high grade (20-100%) in 37.5% of patients (p=0.31). All patients were Her2 negative. The majority of patients were treatment naïve (65.5%, p=0.92). PFS was 37 months for the total sample, 38 months for Palbociclib and 36 months for Ribociclib (log-rank, p = 0.65). Of the total sample, 26 patients (81%) presented at least one Drug Related Problem (DRP).

CONCLUSIONS: This study provides valuable evidence of the clinical results, comparable to those of clinical trials, and points to the importance and reliability of PC data as an RWE source.