DENOSUMAB FOR BONE METASTASES IN ADVANCED CANCER: CLINICAL EXPERIENCE AND SAFETY DATA ACCORDING TO TUMOUR TYPES

Background. Bone metastases are a common event in breast cancer and other tumours, such as prostate and lung cancer. The occurrence of SRE is frequent in presence of bone metastases. The impact of SRE on the quality of life is well established in all tumour types. The use of denosumab, a molecular target drug thatinhibits osteoclast activation, has changed the management of bone metastases in advanced cancer. Methods. Data of 81 pts with bone metastases from breast, prostate and lung cancer, treated in the last year with denosumab, were collected from three Institutions. The occurrence of SRE and safety of denosumab were evaluated in patients that cross from bisphosphonate to denosumab and in pts treated with denosumab upfront. Results. Breast cancer was 70% (N = 57), prostate 16% (N = 13), lung 14% (N = 11). Median age was 69 (34-86), median time from diagnosis to metastasis was 30 months (0-231), bone metastatic sites <3 in 43% pts, = 3 in 57% pts, 51% had extrabone disease. Previous treatment with bisphosphonate was in 38% pts (N = 31), 94% breast (N = 29) and 6% prostate (N = 2), respectively (“cross-over population”). Median time of bisphosphonate treatment was overall 31 months (2-114), 33 mos in breast (2-114), 6 mos in prostate (5.8-6.2). SRE before treatment with denosumab occurred in 54% pts: 80% breast, 7% prostate, 13% lung, respectively. SRE during treatment with denosumab was seen in 5% pts; 50% breast, 25% prostate, 25% lung, respectively. Hypocalcemia was seen in 10% overall: 63% breast, 25% prostate, 12% lung; median time of hypocalcemia was 24 days for all types of tumours. All patients had oral supplementation with calcium as prevention of hypocalcemia. ONJ was seen in 1% of the population. Bone disease progression was seen in 11% pts (56% breast, 22% prostate, 22% lung). Conclusion. Use of denosumab results safe in a population of patients with bone metastases and previous use of bisphosphonate, independently of tumour type; the occurrence of hypocalcemia is easily manageable with a fast recovery; nevertheless, supplementation with calcium is strongly recommended.