Presence of bone metastases (BM) is a factor of poor prognosis in metastatic renal cell carcinoma (mRCC). Radium-223 is a bone targeted active short half-life a-emitter approved in prostate cancer. Its activity in mRCC osteolytic lesions is unknown.
The proof of concept study EIFFEL is a French multicentric phase I/II designed to assess the value of Radium-223 for treatment of mRCC bone lesions. Main objective is to identify the most-successful dose among 4 activity levels: 27.5, 55, 82.5, 110KBq/kg. Primary endpoints are the 6 weeks dose-limiting toxicity (DLT) for escalation cohort and conditional efficacy upon whole-body MRI (WB-MRI) and NaF-PET scan for expansion cohort. In order to optimize the precision of the results, 4 innovative methods were implemented in a context of early phases: 1) a continual reassessment model is used for the 2 phases and expected to provide an optimal dose ( most efficient activity given the acceptable toxicity) 2) Radium-223 to DLT causal relationship assessment uses an intrinsic imputability score to avoid confounding adverse events for DLT qualification, 3) a modified RECIST for bone lesions upon WB-MRI and NaF-PET (considering the entire bone metastatic burden) is used to monitor efficacy in the expansion cohort and 4) efficacy data gathered during the escalation phase will provide prior hypothesis to define the optimal efficacy threshold for the expansion cohort. Analysis of correlations between Radium-223 biodistribution scintigraphy, longitudinal WB-MRI, NaF-PET, and circulating bone remodeling markers will further address important questions in clinical, imagery, metabolism and nuclear medicine domains. The EIFFEL study should provide a large amount of useful data for evaluation and treatment of bone metastasis in mRCC. Results of phase I are expected Q1 2018 and Q4 2019 for final phase II results.
Clinical trial identification
EURACT # 2014-003774-16 - CODE: EIFFEL
Legal entity responsible for the study
ARTIC - Association pour la Recherche de Thérapeutiques Innovantes en Cancérologie Siège social : Service de Cancérologie Médicale Hôpital Européen Georges Pompidou 20-30, rue Leblanc, 75908 Paris Cedex 15
All authors have declared no conflicts of interest.