Randomized clinical trials and real life studies: Comparison of baseline characteristics of patients in oral target therapies for renal cell carcinoma

Introduction: Pivotal Randomized Controlled Trials (RCTs) constitute scientific evidence in support of therapeutic choices when a drug is authorized in the market. In RCTs, patients are selected in a rigorous manner, in order to avoid bias that may influence efficacy assessments. Therefore, patients who take the drug in Real Life Studies (RLSs) are not the same as those participating in RCTs, which, in turn, leads to low data transferability from RCTs to RLS. The objective of this study was to evaluate the differences between RCTs and RLS, in terms of patient baseline characteristics.

Materials and methods: Our study includes all oral target therapies for RCC (Renal Cell Carcinoma) marketed in Europe before March 31, 2019. For each treatment, we considered both RCTs and RLSs, the former gathered from Summary of Product Characteristics published on the European Medicine Agency (EMA) website, and the latter yielded by our search in relevant literature. For each drug considered, we then compared the baseline characteristics of patients included in the RCT samples with those of the samples included in the RLSs using the Chi-squared and Mann-Whitney tests.

Results: We considered six medicines, for a total of 9 pivotal RCTs and 31 RLSs. RCTs reported the same type of patient baseline characteristics, whereas RLSs are more varied in reporting. Some patient baseline characteristics (metastases, previous treatments, etc.) were significantly different between RCTs and RLs. Other characteristics, such as ECOG Performance Status, brain metastases, and comorbidities, liver and kidney failure, are comprised in exclusion criteria of RCTs, though are included in RLS.Discussion and Conclusion: While evaluating equal treatments for the same indications, RCTs and RLSs do not always assess patients with the same characteristics. It would be necessary to produce evidence from RLSs so as to have an idea of treatment effectiveness in patients groups that are not eligible or underrepresented in RCTs.