The safety and efficacy of denosumab for the prevention of skeletal-related events in patients with bone metastases from solid tumors was demonstrated in three international, randomized (1:1), double-blind, active-controlled, noninferiority trials comparing denosumab with zoledronic acid. In all three trials, patients were randomized to receive 120 mg denosumab subcutaneously every 4 weeks or 4 mg zoledronic acid intravenously (IV) every 4 weeks (dose adjusted for reduced renal function). Patients with creatinine clearance less than 30 mL/min were excluded. In each trial, the main outcome measure was demonstration of noninferiority of time to first skeletal-related event (SRE) as compared to zoledronic acid. Supportive outcome measures were superiority of time to first SRE and superiority of time to first and subsequent SRE; testing for these outcome measures occurred if the main outcome measure was statistically significant. An SRE was defined as any of the following: pathologic fracture, radiation therapy to bone, surgery to bone, or spinal cord compression.
Study 20050136 (NCT00321464) enrolled 2046 patients with advanced breast cancer and bone metastasis. Randomization was stratified by a history of prior SRE (yes or no), receipt of chemotherapy within 6 weeks prior to randomization (yes or no), prior oral bisphosphonate use (yes or no), and region (Japan or other countries). Forty percent of patients had a previous SRE, 40% received chemotherapy within 6 weeks prior to randomization, 5% received prior oral bisphosphonates, and 7% were enrolled from Japan. Median age was 57 years, 80% of patients were White, and 99% of patients were women. The median number of doses administered was 18 for denosumab and 17 for zoledronic acid.
Study 20050244 (NCT00330759) enrolled 1776 adults with solid tumors other than breast and castrate-resistant prostate cancer with bone metastasis and multiple myeloma. Randomization was stratified by previous SRE (yes or no), systemic anticancer therapy at time of randomization (yes or no), and tumor type (non-small cell lung cancer, myeloma, or other). Eighty-seven percent were receiving systemic anticancer therapy at the time of randomization, 52% had a previous SRE, 64% of patients were men, 87% were White, and the median age was 60 years. A total of 40% of patients had non-small cell lung cancer, 10% had multiple myeloma, 9% had renal cell carcinoma, and 6% had small cell lung cancer. Other tumor types each comprised less than 5% of the enrolled population. The median number of doses administered was 7 for both denosumab and zoledronic acid.
Study 20050103 (NCT00321620) enrolled 1901 men with castrate-resistant prostate cancer and bone metastasis. Randomization was stratified by previous SRE, PSA level (less than 10 ng/mL or 10 ng/mL or greater) and receipt of chemotherapy within 6 weeks prior to randomization (yes or no). Twenty-six percent of patients had a previous SRE, 15% of patients had PSA less than 10 ng/mL, and 14% received chemotherapy within 6 weeks prior to randomization. Median age was 71 years and 86% of patients were White. The median number of doses administered was 13 for denosumab and 11 for zoledronic acid.
Denosumab delayed the time to first SRE following randomization as compared to zoledronic acid in patients with breast or castrate-resistant prostate cancer (CRPC) with osseous metastases (Table 2). In patients with bone metastasis due to other solid tumors or lytic lesions due to multiple myeloma, denosumab was noninferior to zoledronic acid in delaying the time to first SRE following randomization.
Overall survival and progression-free survival were similar between arms in all three trials.
Table 2. Efficacy Results for Denosumab Compared to Zoledronic Acid
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| Study 20050136 Metastatic Breast Cancer | Study 20050244 Metastatic Solid Tumors or Multiple Myeloma | Study 20050103 Metastatic CRPCa |
Denosumab N = 1026 | Zoledronic Acid N = 1020 | Denosumab N = 886 | Zoledronic Acid N = 890 | Denosumab N = 950 | Zoledronic Acid N = 951 |
| First On-study SRE |
| Number of Patients who had SREs (%)
| 315 (30.7)
| 372 (36.5)
| 278 (31.4)
| 323 (36.3)
| 341 (35.9)
| 386 (40.6)
|
| Components of First SRE
|
| Radiation to Bone
| 82 (8.0)
| 119 (11.7)
| 119 (13.4)
| 144 (16.2)
| 177 (18.6)
| 203 (21.3)
|
| Pathological Fracture
| 212 (20.7)
| 238 (23.3)
| 122 (13.8)
| 139 (15.6)
| 137 (14.4)
| 143 (15.0)
|
| Surgery to Bone
| 12 (1.2)
| 8 (0.8)
| 13 (1.5)
| 19 (2.1)
| 1 (0.1)
| 4 (0.4)
|
| Spinal Cord Compression
| 9 (0.9)
| 7 (0.7)
| 24 (2.7)
| 21 (2.4)
| 26 (2.7)
| 36 (3.8)
|
| Median Time to SRE (months)
| NRb
| 26.4
| 20.5
| 16.3
| 20.7
| 17.1
|
| Hazard Ratio (95% CI)
| 0.82 (0.71, 0.95)
| 0.84 (0.71, 0.98)
| 0.82 (0.71, 0.95)
|
| Noninferiority p-value
| < 0.001
| < 0.001
| < 0.001
|
| Superiority p-valuec
| 0.010
| 0.060
| 0.008
|
| First and Subsequent SREd |
| Mean Number/Patient
| 0.46
| 0.60
| 0.44
| 0.49
| 0.52
| 0.61
|
| Rate Ratio (95% CI)
| 0.77 (0.66, 0.89)
| 0.90 (0.77, 1.04)
| 0.82 (0.71, 0.94)
|
| Superiority p-valuee
| 0.001
| 0.145
| 0.009
|