Corticodependent or Corticoresistant Brain Radionecrosis After Radiotherapy for Brain Metastases: a Multicentre Randomized, Controlled Double-blind Phase III Study, Comparing Bevacizumab Versus Placebo
Brain metastases (BM) afflict a significant portion of cancer patients, ranging from 10% to 50%, leading to debilitating symptoms and diminished quality of life, thereby impacting overall survival. Treatment options typically include surgery, stereotactic radiosurgery (SRS), and whole brain radiotherapy (WBRT). SRS has emerged as the preferred focal treatment due to its efficacy, delivering ablative doses with notable overall survival benefits, especially for single BM or postoperative cases, while being less invasive than neurosurgery and capable of addressing inoperable sites and multiple lesions. Contrastingly, WBRT is now reserved for select cases with multiple BMs ineligible for SRS, owing to its lower rate of neurocognitive toxicities and high local control rates at one year. Despite its advantages, SRS can engender late side effects, with cerebral radio necrosis (RN) being the most common, occurring in approximately 10% of patients treated. The exact pathophysiology of RN remains unclear but is thought to involve vascular injury, immune-mediated mechanisms, and direct neuronal effects, culminating in radiological changes or symptomatic manifestations necessitating treatment. Corticosteroids are the mainstay therapy, albeit with associated side effects and instances of cortico-resistance or cortico-dependence. Bevacizumab, an anti-VEGF agent, has shown promise in small studies but awaits validation in larger trials. Consequently, a randomized phase III trial seeks to evaluate the efficacy of adding bevacizumab to standard corticosteroid therapy in patients with symptomatic RN. The trial aims to determine if this combination therapy yields superior symptomatic improvement compared to corticosteroids alone. RN will be diagnosed using multimodal imaging, and the primary objective is to assess the efficacy of bevacizumab in reducing corticosteroid usage and neurological symptoms associated with RN at three months. Secondary endpoints include toxicities, quality of life, imaging changes, and response duration. Additionally, an ancillary study will explore correlations between initial imaging parameters and treatment response, as well as changes in biological parameters with bevacizumab therapy.
• Patient with a diagnosis of radionecrosis based on a clinical onset of symptoms and radiological findings of RN following radiotherapy, with or without pathological confirmation:
∙ MRI evidence to support the diagnosis of RN (transient increase in irradiated lesion volume -FLAIR hypersignal and/or enhanced portion- without rCBV increase) COMBINED with nuclear medicine imaging:
∙ biphasic 18FDG-PET-TDM/MRI according to Horky or 18F-FDOPA with stage 0-1 according to Lizarraga;
• Symptoms are persistent or worsening despite administration of corticosteroids: at least 1 mg/kg/d of prednisolone or equivalent:
∙ Corticoresistant: neurological symptoms despite administration of at least 2 weeks of 1 mg/kg/d prednisolone or equivalent; Corticodependant: worsening of neurological signs or symptoms after an initial improvement when weaning off steroids at a dose \< 0.5 mg/kg/d prednisolone or equivalent;
• Patients must have received the last cranial irradiation with photons or proton therapy for brain metastases ≥ 3 months with one or more sequences;
• Age≥18-year-old;
• ECOG performance status score ≤ 3
• Life expectancy of at least 3 months assessed by graded prognostic score (DS-GPA) score 0.5 or greater;
• Patient who has never received Bevacizumab for the indication of radionecrosis.
• Adequate organ function:
∙ Bone marrow function
• Absolute Neutrophil Count (ANC) ≥ 1,500/mm3 Platelet Count ≥ 100,000/mm3, Haemoglobin ≥ 10 g/dL (allowing transfusion or other intervention to achieve this minimum haemoglobin) Coagulation
• International normalized ratio (INR) or prothrombin time \< 1.5 × ULN Renal function
• No proteinuria with urine dipstick for proteinuria \> 2+
• Serum creatinine ≤1.5 x ULN or creatinine clearance ≥50 mL/min (measured or calculated using the CDK-EPI formula) Hepatic Function
• Total bilirubin ≤1.5 x the upper limit of normal (ULN)
• Alanine transaminase (ALT) and aspartate aminotransferase (AST) ≤3 x ULN
‣ Women of childbearing potential must use effective contraceptive measures during the treatment and for 6 months following its cessation;
⁃ Signed informed consent;
⁃ Patient affiliated to a social security scheme.