Women with stage 4 breast cancer are being recruited for a trial with a combination of two oncology drugs, avelumab and radium-223.
Stage 4 breast cancer has only a 25% survival rate after 5 years and a trial, funded by the Breast Cancer Now Catalyst Programme, aims to explore the value of combining radium-223 and avelumab in patients with the disease. Avelumab, a monoclonal antibody, is already licensed for the treatment of metastatic Merkel cell carcinoma and advanced renal cell carcinoma. Its mode of action involves blockage of the protein, PD-L1 found on tumour cells. PD-L1 decreases the immune system’s ability to kill cancer cells, hence its blockage enables the immune system to recognise and destroy cancer cells. In fact, some preliminary data suggests that avelumab has an acceptable safety profile and clinical activity in a subset of patients with metastatic breast cancer.
Radium-223, brand name, Xofigo, is radiopharmaceutical which is also licensed for use as either mono-therapy or in combination with luteinising hormone releasing hormone (LHRH) for the treatment of adult patients with metastatic castration-resistant prostate cancer (mCRPC), symptomatic bone metastases and no known visceral metastases. Radium-223 is a potentially important treatment in stage 4 breast cancer because the most common distal site for spreading is bone in up to 51% of cases. Radium-223 selectively binds to areas of increased bone turnover in bone metastases and emits high-energy alpha particles which have a short range and therefore this limits damage to adjacent areas of tissue. Although radium-223 has not been used in metastatic breast cancer, a second on-going trial is examining feasibility and safety of combining radium-223 given on a 6-weekly schedule, in combination with orally administered capecitabine in breast cancer patients with bone metastases.
The avelumab and radium-223 trial is led by Professor Janet Brown at the University of Sheffield, and run by the Clinical Trials Research Unit at the University of Leeds. If successful, this combination of drugs could provide a new way to treat secondary breast cancer.
