Assessment of denosumab treatment effects and imaging response in patients with giant cell tumor of bone.

BACKGROUND: Denosumab has been shown to reduce tumor size and progression, reform mineralized bone, and increase intralesional bone density in patients with giant cell tumor of bone (GCTB); however, radiologic assessment of tumors in bone is challenging. The study objective was to assess tumor response to denosumab using three different imaging parameters in a prespecified analysis in patients with GCTB from two phase 2 studies. METHODS: The studies enrolled adults and adolescents (skeletally mature and at least 12 years of age) with radiographically measurable GCTB that were given denosumab 120 mg every 4 weeks, with additional doses on days 8 and 15 of cycle 1. The proportion of patients with an objective tumor response was assessed using either Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST), European Organisation for Research and Treatment of Cancer response criteria (positron emission tomography [PET] scan criteria), or inverse Choi density/size (ICDS) criteria. Target lesions were measured by computed tomography or magnetic resonance imaging (both studies), PET (study 2 only), or plain film radiograph (study 2 only). RESULTS: Most patients (71.6%) had an objective tumor response by at least one response criteria. Per RECIST, 25.1% of patients had a response; per PET scan criteria, 96.2% had a response; per ICDS, 76.1% had a response. 68.5% had an objective tumor response ≥ 24 weeks. Using any criteria, crude incidence of response ranged from 56% (vertebrae/skull) to 91% (lung/soft tissue), and 98.2% had tumor control ≥ 24 weeks. Reduced PET avidity appeared to be an early sign of response to denosumab treatment. CONCLUSION: Modified PET scan criteria and ICDS criteria indicate that most patients show responses and higher benefit rates than modified RECIST, and therefore may be useful for early assessment of response to denosumab. TRIAL REGISTRATION: ClinicalTrials.gov Clinical Trials Registry NCT00396279 (retrospectively registered November 6, 2006) and NCT00680992 (retrospectively registered May 20, 2008).

Pain and analgesic use associated with skeletal-related events in patients with advanced cancer and bone metastases.

PURPOSE: Bone metastases secondary to solid tumors increase the risk of skeletal-related events (SREs), including the occurrence of pathological fracture (PF), radiation to bone (RB), surgery to bone (SB), and spinal cord compression (SCC). The aim of this study was to evaluate the impact of SREs on patients' pain, analgesic use, and pain interference with daily functioning. METHODS: Data were combined from patients with solid tumors and bone metastases who received denosumab or zoledronic acid across three identically designed phase 3 trials (N = 5543). Pain severity (worst pain) and pain interference were assessed using the Brief Pain Inventory at baseline and each monthly visit. Analgesic use was quantified using the Analgesic Quantification Algorithm. RESULTS: The proportion of patients with moderate/severe pain and strong opioid use generally increased in the 6 months preceding an SRE and remained elevated, while they remained relatively consistent over time in patients without an SRE. Regression analysis indicated that all SRE types were significantly associated with an increased risk of progression to moderate/severe pain and strong opioid use. PF, RB, and SCC were associated with significantly greater risk of pain interference overall. Results were similar for pain interference with emotional well-being. All SRE types were associated with significantly greater risk of pain interference with physical function. CONCLUSIONS: SREs are associated with increased pain and analgesic use in patients with bone metastases. Treatments that prevent SREs may decrease pain and the need for opioid analgesics and reduce the impact of pain on daily functioning.

Safety of long-term denosumab therapy: results from the open label extension phase of two phase 3 studies in patients with metastatic breast and prostate cancer.

PURPOSE: Zoledronic acid (ZA) or denosumab treatment reduces skeletal-related events; however, the safety of prolonged therapy has not been adequately studied. Here, we describe safety results of extended denosumab therapy in patients with bone metastases from the open-label extension phase of two phase 3 trials. METHODS: Patients with metastatic breast or prostate cancer received subcutaneous denosumab 120 mg Q4W or intravenous ZA 4 mg Q4W in a double-blinded fashion. Denosumab demonstrated superior efficacy in the blinded treatment phase; thus, patients were offered open-label denosumab for up to an additional 2 years. RESULTS: Cumulative median (Q1, Q3) denosumab exposure was 19.1 (9.2, 32.2) months in the breast cancer trial (n = 1019) and 12.0 (5.6, 21.3) months in the prostate cancer trial (n = 942); 295 patients received denosumab for >3 years. No new safety signals were identified during the open-label phase, or among patients who switched from ZA to denosumab. During the blinded treatment phase, exposure-adjusted subject incidences of osteonecrosis of the jaw (ONJ) were 49 (1.9%) and 31 (1.2%) in the denosumab and ZA groups, respectively. In total, 32 (6.9%) and 25 (5.5 %) new cases of ONJ (not adjusted for exposure) were reported for patients continuing and switching to denosumab, respectively. The incidences of hypocalcemia were 4.3 and 3.1%, in patients continuing and switching to denosumab, respectively. CONCLUSION: These results describe the safety profile of denosumab after long-term exposure, or after switching to denosumab from ZA. No new safety signals were identified. Hypocalcemia rates were similar in the blinded treatment and open-label phases. ONJ rates increased with increasing exposure to antiresorptives, consistent with previous reports.

Hypocalcaemia in patients with metastatic bone disease treated with denosumab.

BACKGROUND: This analysis was performed to further characterise treatment-emergent hypocalcaemia in patients with bone metastases receiving denosumab. METHODS: Laboratory abnormalities and adverse events of hypocalcaemia in patients with metastatic bone disease were analysed using data from three identically designed phase 3 trials of subcutaneous denosumab 120 mg (n = 2841) versus intravenous zoledronic acid 4 mg (n = 2836). RESULTS: The overall incidence of laboratory events of hypocalcaemia grade ⩾ 2 was higher with denosumab (12.4%) than with zoledronic acid (5.3%). Hypocalcaemia events were primarily grade 2 in severity and usually occurred within the first 6 months of treatment. Patients who reported taking calcium and/or vitamin D supplements had a lower incidence of hypocalcaemia. Prostate cancer or small-cell lung cancer, reduced creatinine clearance and higher baseline bone turnover markers of urinary N-telopeptide of type I collagen (uNTx; > 50 versus ⩽ 50 nmol/mmol) and bone-specific alkaline phosphatase (BSAP; > 20.77 µg/L [median] versus ⩽ 20.77 µg/L) values were important risk factors for developing hypocalcaemia. The risk associated with increased baseline BSAP levels was greater among patients who had > 2 bone metastases at baseline versus those with ⩽ 2 bone metastases at baseline. CONCLUSION: Hypocalcaemia was more frequent with denosumab versus zoledronic acid, consistent with denosumab's greater antiresorptive effect. Low serum calcium levels and potential vitamin D deficiency should be corrected before initiating treatment with a potent osteoclast inhibitor, and corrected serum calcium levels should be monitored during treatment. Adequate calcium and vitamin D intake appears to substantially reduce the risk of hypocalcaemia.

The role of denosumab in the prevention of hypercalcaemia of malignancy in cancer patients with metastatic bone disease.

BACKGROUND: We compared the activity of denosumab with zoledronic acid for delaying or preventing hypercalcaemia of malignancy (HCM) in patients with advanced cancer and bone metastases or with multiple myeloma. METHODS: Patient-level data were combined from two identically designed, randomised, double-blind, active-controlled, phase III trials of advanced cancer patients with breast cancer and other solid tumours (excluding breast or prostate cancer) or multiple myeloma. End-points included time to first on-study HCM, time to first and subsequent on-study HCM, proportion of patients experiencing HCM and proportion of patients experiencing recurrent HCM. RESULTS: Denosumab significantly delayed the time to first on-study HCM, representing a 37% reduction in the hazard ratio (HR) compared with zoledronic acid (HR, 0.63; 95% confidence interval (CI): 0.41-0.98; P = 0.042) and reduced the risk of developing recurrent HCM (time to first and subsequent on-study HCM) by 52% (rate ratio, 0.48; 95% CI: 0.29-0.81; P = 0.006). The median time on study was 12.9 months. Fewer patients receiving denosumab compared with zoledronic acid experienced an HCM event (1.7% versus 2.7%; P = 0.028). Of the 84 patients experiencing an HCM event, 40% of those receiving zoledronic acid experienced >1 event of HCM compared with 31% of those receiving denosumab. CONCLUSION: Denosumab treatment was more efficacious than treatment with zoledronic acid in delaying or preventing HCM in advanced cancer patients with breast cancer, other solid tumours or multiple myeloma.

Denosumab for treatment of hypercalcemia of malignancy.

CONTEXT: Hypercalcemia of malignancy (HCM) in patients with advanced cancer is often caused by excessive osteoclast-mediated bone resorption. Patients may not respond to or may relapse after iv bisphosphonate therapy. OBJECTIVE: We investigated whether denosumab, a potent inhibitor of osteoclast-mediated bone resorption, reduces serum calcium in patients with bisphosphonate-refractory HCM. DESIGN, SETTING, AND PARTICIPANTS: In this single-arm international study, participants had serum calcium levels corrected for albumin (CSC) >12.5 mg/dL (3.1 mmol/L) despite bisphosphonates given >7 and ≤30 days before screening. INTERVENTION: Patients received 120 mg sc denosumab on days 1, 8, 15, and 29 and then every 4 weeks. MAIN OUTCOME MEASURES: The primary endpoint was the proportion of patients with CSC ≤11.5 mg/dL (2.9 mmol/L) (response) by day 10. Secondary endpoints included response by visit, duration of response, and the proportion of patients with a complete response (CSC ≤10.8 mg/dL [2.7 mmol/L]) by day 10 and during the study. RESULTS: Patients (N = 33) had solid tumors or hematologic malignancies. By day 10, 21 patients (64%) reached CSC ≤11.5 mg/dL, and 12 patients (33%) reached CSC ≤10.8 mg/dL. During the study, 23 patients (70%) reached CSC ≤11.5 mg/dL, and 21 patients (64%) reached CSC ≤10.8 mg/dL. Estimated median response duration was 104 days. The most common serious adverse events were hypercalcemia worsening (5 patients, 15%) and dyspnea (3 patients, 9%). CONCLUSIONS: In patients with HCM despite recent iv bisphosphonate treatment, denosumab lowered serum calcium in 64% of patients within 10 days, inducing durable responses. Denosumab may offer a new treatment option for HCM.

Effects of denosumab on pain and analgesic use in giant cell tumor of bone: interim results from a phase II study.

BACKGROUND: Giant cell tumor of bone (GCTB) is an aggressive primary osteolytic tumor. GCTB often involves the epiphysis, usually causing substantial pain and functional disability. Denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor κΒ ligand (RANKL), is an effective treatment option for patients with advanced GCTB. This analysis of data from an ongoing, open-label study describes denosumab's effects on pain and analgesic use in patients with GCTB. MATERIAL AND METHODS: Patients with unresectable disease (e.g. sacral or spinal GCTB, or multiple lesions including pulmonary metastases) were enrolled into Cohort 1 (N = 170), and patients with resectable disease whose planned surgery was associated with severe morbidity (e.g. joint resection, limb amputation, or hemipelvectomy) were enrolled into Cohort 2 (N = 101). Patients received denosumab (120 mg) subcutaneously every four weeks, with additional doses on study days 8 and 15. Patients assessed worst pain severity with the Brief Pain Inventory - Short Form (BPI-SF) at baseline, at each visit for the first six months, and every three months thereafter. RESULTS: Clinically relevant pain improvement was reported by 29% of patients in Cohort 1 and 35% in Cohort 2 during week 1 and by ≥ 50% of patients in each cohort at each study visit from months 2-30. Median time to clinically relevant improvement was 30 (95% CI 16, 57) days in Cohort 1 and 15 (95% CI 15, 29) days in Cohort 2. Results in patients with moderate/severe pain at baseline were similar. Fewer than 30% of patients in Cohort 1 and 10% in Cohort 2 experienced clinically relevant pain worsening at any visit through 27 months. Most patients had no/low analgesic use during the study. CONCLUSION: Most patients treated with denosumab experienced clinically relevant decreases in pain within two months.

Assessing analgesic use in patients with advanced cancer: development of a new scale--the Analgesic Quantification Algorithm.

OBJECTIVE: Many patients with advanced cancer frequently use analgesic medications for their pain. Systematically assessing and quantifying changes in analgesic use remains challenging in the clinical trials setting. Currently, there is no sensitive scale for categorizing the intensity of analgesic medications to understand the reasons for changes in patient-reported pain. We assessed whether the Analgesic Quantification Algorithm (AQA) is more sensitive than the World Health Organization Analgesic Treatment Ladder (WHO-AL) for quantifying analgesic medication use among patients with advanced cancer. METHODS: An expanded equianalgesic potency conversion table was developed to establish oral morphine equivalents for use in the AQA. Categories of opioid use were selected to increase sensitivity within the higher dose range of opioids and to better capture increases in analgesic dose intensity. The resulting 8-point AQA scale corresponds to no analgesic use, non-opioid analgesics, weak opioids only, ≤75 mg, >75-150 mg, >150-300 mg, >300-600 mg, and >600 mg oral morphine equivalents per day. Baseline and 6-month analgesic data from a clinical trial of cancer patients were compared for each instrument. RESULTS: At both time points, the 4-point WHO-AL demonstrated a ceiling effect with a clustering of patients in the strong opioid category, whereas the AQA resulted in a distribution of scores throughout the eight categories, including the five strong opioid categories. CONCLUSIONS: The AQA represents a more sensitive measure of analgesic use than the WHO-AL, and may better determine whether changes in pain assessments in clinical trials are due to the intervention or changes in analgesic use.

Health state utilities for skeletal-related events secondary to bone metastases.

INTRODUCTION: Patients with bone metastases often experience skeletal-related events (SREs). Although cost-utility models are used to examine treatments for metastatic cancer, limited information is available on utilities of SREs. The purpose of this study was to estimate the disutility of four SREs: spinal cord compression, pathological fracture, radiation to bone, and surgery performed to stabilize a bone. METHODS: General population participants from the UK and Canada completed time trade-off (TTO) interviews to assess the utility of health states drafted based on literature review, clinician interviews, and patient interviews. Respondents first rated a health state describing cancer with bone metastases. Then, the SREs were added to this health state. RESULTS: Interviews were completed with 187 participants (50.8 % male, 80.2 % white). Cancer with bone metastases without an SRE had a mean utility of 0.47 (SD = 0.43) on a standard utility scale (1 = full health, 0 = death). Of the SREs, spinal cord compression was associated with the greatest disutility (i.e., the utility decrease): -0.32 with paralysis and -0.22 without paralysis. Surgery had a disutility of -0.07. Leg, arm, and rib fractures had disutilities of -0.06, -0.04, and -0.03. Two weeks of daily radiation treatment had a disutility of -0.06, while two radiation appointments had the smallest impact on utility (-0.02). CONCLUSION: All SREs were associated with statistically significant utility decreases, suggesting a perceived impact on quality of life beyond the impact of cancer with bone metastases. The resulting disutilities may be used in cost-utility models examining treatments to prevent SREs secondary to bone metastases.

Utilities associated with subcutaneous injections and intravenous infusions for treatment of patients with bone metastases.

INTRODUCTION: Although cost-utility models are often used to estimate the value of treatments for metastatic cancer, limited information is available on the utility of common treatment modalities. Bisphosphonate treatment for bone metastases is frequently administered via intravenous infusion, while a newer treatment is administered as a subcutaneous injection. This study estimated the impact of these treatment modalities on health state preference. METHODS: Participants from the UK general population completed time trade-off interviews to assess the utility of health state vignettes. Respondents first rated a health state representing cancer with bone metastases. Subsequent health states added descriptions of treatment modalities (ie, injection or infusion) to this basic health state. The two treatment modalities were presented with and without chemotherapy, and infusion characteristics were varied by duration (30 minutes or 2 hours) and renal monitoring. RESULTS: A total of 121 participants completed the interviews (52.1% female, 76.9% white). Cancer with bone metastases had a mean utility of 0.40 on a standard utility scale (1 = full health; 0 = dead). The injection, 30-minute infusion, and 2-hour infusion had mean disutilities of -0.004, -0.02, and -0.04, respectively. The mean disutility of the 30-minute infusion was greater with renal monitoring than without. Chemotherapy was associated with substantial disutility (-0.17). When added to health states with chemotherapy, the mean disutilities of injection, 30-minute infusion, and 2-hour infusion were -0.02, -0.03, and -0.04, respectively. The disutility associated with injection was significantly lower than the disutility of the 30-minute and 2-hour infusions (P < 0.05), regardless of chemotherapy status. CONCLUSION: Respondents perceived an inconvenience with each type of treatment modality, but injections were preferred over infusions. The resulting utilities may be used in cost-utility models examining the value of treatments for the prevention of skeletal-related events in patients with bone metastases.

Pain and health-related quality of life in patients with advanced solid tumours and bone metastases: integrated results from three randomized, double-blind studies of denosumab and zoledronic acid.

PURPOSE: This analysis evaluated patient-reported outcomes and analgesic use in patients with bone metastases from solid tumours across three comparative studies of denosumab and zoledronic acid. METHODS: Pooled data were analysed from three identically designed double-blind phase III studies comparing subcutaneous denosumab 120 mg with intravenous zoledronic acid 4 mg monthly in patients with bone metastases from breast cancer (n = 2,046), castration-resistant prostate cancer (n = 1,901) or other solid tumours (n = 1,597). Pain severity, pain interference, health-related quality of life and analgesic use were quantified. RESULTS: At baseline, approximately half of patients had no/mild pain (53 % [1,386/2,620] denosumab; 50 % [1,297/2,578] zoledronic acid). Denosumab delayed onset of moderate/severe pain by 1.8 months (median, 6.5 vs 4.7 months; hazard ratio, 0.83; 95 % CI, 0.76-0.92; p < 0.001; 17 % risk reduction) and clinically meaningful increases in overall pain interference by 2.6 months (median, 10.3 vs 7.7 months; hazard ratio, 0.83; 95 % CI, 0.75-0.92; p < 0.001; 17 % risk reduction) compared with zoledronic acid. Strong opioid use and worsening of health-related quality of life were less common with denosumab. CONCLUSIONS: Across three large studies of patients with advanced solid tumours and bone metastases, denosumab prevented progression of pain severity and pain interference more effectively than zoledronic acid.

Pain outcomes in patients with advanced breast cancer and bone metastases: results from a randomized, double-blind study of denosumab and zoledronic acid.

BACKGROUND: In this study, the authors evaluated the effect of denosumab versus zoledronic acid (ZA) on pain in patients with advanced breast cancer and bone metastases. METHODS: The prevention of pain, reduction in pain interference with daily life activities, and the proportion of patients requiring strong opioid analgesics were assessed in a randomized, double-blind, double-dummy phase 3 study comparing denosumab with ZA for preventing skeletal-related events in 2046 patients who had breast cancer and bone metastases. Patients completed the Brief Pain Inventory-Short Form at baseline and monthly thereafter. RESULTS: Fewer patients who received denosumab reported a clinically meaningful worsening of pain severity (≥2-point increase) from baseline compared with patients who received ZA, and a trend was observed toward delayed time to pain worsening with denosumab versus ZA (denosumab, 8.5 months; ZA, 7.4 months; P = .08). In patients who had no/mild pain at baseline, a 4-month delay in progression to moderate/severe pain was observed with denosumab compared with ZA (9.7 months vs 5.8 months; P = .002). Denosumab delayed the time to increased pain interference by approximately 1 month compared with ZA (denosumab, 16.0 months; ZA, 14.9 months; P = .09). The time to pain improvement (P = .72) and the time to decreased pain interference (P = .92) were similar between the groups. Fewer denosumab-treated patients reported increased analgesic use from no/low use at baseline to strong opioid use. CONCLUSIONS: Denosumab demonstrated improved pain prevention and comparable pain palliation compared with ZA. In addition, fewer denosumab-treated patients shifted to strong opioid analgesic use.

Superiority of denosumab to zoledronic acid for prevention of skeletal-related events: a combined analysis of 3 pivotal, randomised, phase 3 trials.

BACKGROUND: Patients with bone metastases from advanced cancer often experience skeletal-related events (SRE), which cause substantial pain and morbidity. Denosumab, a fully human monoclonal antibody that inhibits RANK Ligand (RANKL), is a novel bone-targeted agent with a distinct mechanism of action relative to the bisphosphonate zoledronic acid, for prevention of SRE. This pre-planned analysis evaluates the efficacy and safety of denosumab versus zoledronic acid across three pivotal studies. METHODS: Patient-level data from three identically designed, randomised, double-blind, active-controlled, phase 3 trials of patients with breast cancer, prostate cancer, other solid tumours or multiple myeloma were combined. End-points included time to first SRE, time to first and subsequent (multiple) SRE, adverse events, time to disease progression and overall survival. FINDINGS: Denosumab was superior to zoledronic acid in delaying time to first on-study SRE by a median 8.21months, reducing the risk of a first SRE by 17% (hazard ratio, 0.83 [95% confidence interval (CI): 0.76-0.90]; P<0.001). Efficacy was demonstrated for first and multiple events and across patient subgroups (prior SRE status; age). Disease progression and overall survival were similar between the treatments. In contrast to zoledronic acid, denosumab did not require monitoring or dose modification/withholding based on renal status, and was not associated with acute-phase reactions. Hypocalcaemia was more common for denosumab. Osteonecrosis of the jaw occurred at a similar rate (P=0.13). CONCLUSION: Denosumab was superior to zoledronic acid in preventing SRE with favourable safety and convenience in patients with bone metastases from advanced cancer.

Bone-related complications and quality of life in advanced breast cancer: results from a randomized phase III trial of denosumab versus zoledronic acid.

PURPOSE: Denosumab was shown to be superior to zoledronic acid in preventing skeletal related events (SRE) in patients with breast cancer and bone metastases in a randomized, double-blind phase III study. We evaluated further results from this study related to skeletal complications and health-related quality of life (HRQoL). EXPERIMENTAL DESIGN: Patients were randomized 1:1 to receive subcutaneous denosumab 120 mg (n = 1,026) and intravenous placebo, or intravenous zoledronic acid 4 mg (n = 1,020) and subcutaneous placebo every 4 weeks. Analyses reported here include the proportion of patients with one or multiple on-study SREs, time to first radiation to bone, time to first SRE or hypercalcemia of malignancy, and change in HRQoL (functional assessment of cancer therapy-general). RESULTS: Fewer patients receiving denosumab than zoledronic acid had an on-study SRE (31% vs. 36%, P = 0.006). The incidence of first radiation to bone was 12% (n = 123) with denosumab versus 16% (n = 162) with zoledronic acid. Denosumab prolonged the time to first radiation to bone by 26% versus zoledronic acid (HR, 0.74; 95% confidence interval [CI], 0.59-0.94, P = 0.012) and prolonged the time to first SRE or hypercalcemia of malignancy by 18% (HR, 0.82; 95% CI, 0.70-0.95; P = 0.007). Ten percent more patients had a clinically meaningful improvement in HRQoL with denosumab relative to zoledronic acid, regardless of baseline pain levels. CONCLUSIONS: Denosumab was superior to zoledronic acid in reducing bone-related complications of metastatic breast cancer and maintained HRQoL, providing an efficacious, well-tolerated treatment option for patients with bone metastases from breast cancer.

The development of denosumab for the treatment of diseases of bone loss and cancer-induced bone destruction.

Denosumab is a fully human monoclonal antibody against RANK ligand (RANKL), an essential cytokine for the formation, function, and survival of osteoclasts. The role of excessive RANKL as a contributor to conditions characterized by bone loss or bone destruction has been well studied. With its novel mechanism of action, denosumab offers a significant advance in the treatment of postmenopausal osteoporosis; bone loss associated with hormone ablation therapy in women with breast cancer and men with prostate cancer; and the prevention of skeletal-related events in patients with bone metastases from solid tumors by offering clinical benefit to these patients in need.

Denosumab compared with zoledronic acid for the treatment of bone metastases in patients with advanced breast cancer: a randomized, double-blind study.

PURPOSE: This randomized study compared denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor κ B (RANK) ligand, with zoledronic acid in delaying or preventing skeletal-related events (SREs) in patients with breast cancer with bone metastases. PATIENTS AND METHODS: Patients were randomly assigned to receive either subcutaneous denosumab 120 mg and intravenous placebo (n = 1,026) or intravenous zoledronic acid 4 mg adjusted for creatinine clearance and subcutaneous placebo (n = 1,020) every 4 weeks. All patients were strongly recommended to take daily calcium and vitamin D supplements. The primary end point was time to first on-study SRE (defined as pathologic fracture, radiation or surgery to bone, or spinal cord compression). RESULTS: Denosumab was superior to zoledronic acid in delaying time to first on-study SRE (hazard ratio, 0.82; 95% CI, 0.71 to 0.95; P = .01 superiority) and time to first and subsequent (multiple) on-study SREs (rate ratio, 0.77; 95% CI, 0.66 to 0.89; P = .001). Reduction in bone turnover markers was greater with denosumab. Overall survival, disease progression, and rates of adverse events (AEs) and serious AEs were similar between groups. An excess of renal AEs and acute-phase reactions occurred with zoledronic acid; hypocalcemia occurred more frequently with denosumab. Osteonecrosis of the jaw occurred infrequently (2.0%, denosumab; 1.4%, zoledronic acid; P = .39). CONCLUSION: Denosumab was superior to zoledronic acid in delaying or preventing SREs in patients with breast cancer metastatic to bone and was generally well tolerated. With the convenience of a subcutaneous injection and no requirement for renal monitoring, denosumab represents a potential treatment option for patients with bone metastases.

Transmembrane and soluble isoforms of heparin-binding epidermal growth factor-like growth factor regulate distinct processes in the pancreas.

BACKGROUND & AIMS: Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is produced as a type-I, single-pass transmembrane protein that can be cleaved to release a diffusible peptide. HB-EGF, often overexpressed in damaged or diseased epithelium, is normally expressed in pancreatic islets, but its function is not understood. METHODS: To understand the function of each isoform of HB-EGF, we made transgenes expressing either a constitutively transmembrane or a constitutively secreted protein. RESULTS: The transmembrane isoform was not an inert precursor protein, but a functional molecule, downregulating the glucose-sensing apparatus of pancreatic islets. Conversely, the secreted form of HB-EGF improved islet function, but had severe fibrotic and neoplastic effects on surrounding tissues. Each isoform had a more severe phenotype than that of full-length HB-EGF, even though the full-length protein was efficiently cleaved, thus producing both isoforms, suggesting that a level of regulation was lost by separating the isoforms. CONCLUSIONS: This work demonstrates that islet function depends on the ratio of cleaved to uncleaved HB-EGF and that the transmembrane intermediate, while deleterious to islet function, is necessary to restrict action of soluble HB-EGF away from surrounding tissue.