A Comparative Study of Pravastatin vs Placebo as Primary Prevention of Severe Subcutaneous Breast Fibrosis in Hyper-radiosensitive Identified Patients With Breast Cancer

Overview

-Interventional trials aim at preventing severe RIF occurrence in BC patients selected by individual radiosensitivity: PRAVAPREV-01 will be the first interventional double blind trial that will offer a personalised strategy to breast cancer patients who will be treated with adjuvant RT after breast conserving surgery: * By assessing individual risk of severe RIF development * By offering a statin targeted therapy to the high-risk patients identified.

According to VICAN5 report, near 50% of survivorship breast cancer (BC) patients suffered impairment of their QoL 2 and 5 years after BC diagnosis compared to overall population. In France, adjuvant radiotherapy (RT) is performed to 88.5% of BC patients. Severe toxicities after adjuvant RT such as radio-induced fibrosis (RIF) in BC patients can have a negative impact on quality of life and a marked effect on subsequent psychological outcomes. However, current practice standards commonly prescribe RT irrespective of the individual radiosensitivity risk. This study propose to identify BC at high RIF risk and to prevent severe RIF occurrence in this selected BC population by the use of anti-fibrotic agent (pravastatin). How to identify the risk of individual radiosensitivity? Since 1995 a rapid (72 h) radiosensitivity assay based on flow cytometric assessment of radiation-induced CD8 T-lymphocyte apoptosis (RILA) has been developed. A lot of laboratory observed a significant relationship between RILA and toxicities occurrence, in particular in a prospective multicenter French study (NCT00893035, Azria et al, EBioMedicine 2015). Data from this study have validated the use of the NovaGray RILA Breast® test in clinical routine and enabled its CE-mark obtention in 2016. How to prevent severe RIF occurrence? Few phase II clinical trials have assessed anti-fibrotic properties of some drugs in a preventive setting (pentoxyfilline/vitamine E, ambroxol, ACE inhibitors, amifostine) and showed controversial results regarding efficacy and/ or tolerance. To date, no large phase III clinical trial confirmed these therapeutic strategies in the prevention of severe breast RIF occurrence. Since 2000, Rho/ROCK pathway inhibition habe been showed, in particular by Pravastatin, was able to prevent and cure severe RIF in different preclinical RIF models. Based on those results, a phase II clinical trial PRAVACUR (NCT01268202) has been conducted,assessing efficacy of 12-months daily pravastatin delivered in patients with established RIF after head and neck radiotherapy. The use of Pravastatin significantly reduced RIF grade in 51% of patients (clinical assessment at 12-months) without any rebound effect after pravastatin completion (Bourgier IJROBP 2019). This hypothesis is therefore that pravastatin given in a preventive approach will significantly decrease severe breast fibrosis occurrence in a highly selected breast cancer population treated by adjuvant breast RT and considered at high risk of RIF (tailored by the NovaGray RILA Breast® test).