Osteonecrosis of the jaw among patients with cancer treated with denosumab or zoledronic acid: Results of a regulator-mandated cohort postauthorization safety study in Denmark, Norway, and Sweden.

BACKGROUND: Osteonecrosis of the jaw (ONJ) is an adverse effect of antiresorptive treatment. This study estimated incidence proportions and incidence rates of ONJ in cancer patients with bone metastases from solid tumors treated for the prevention of skeletal-related events in routine clinical practice. METHODS: This cohort study in Denmark, Norway, and Sweden in 2011-2018 included 3 treatment cohorts: a denosumab inception cohort (DEIC), a zoledronic acid inception cohort (ZAIC), and a denosumab-switch cohort (DESC). The authors estimated 1- to 5-year incidence proportions and incidence rates of ONJ overall, by cancer site (breast, prostate, or other solid tumor), and by country. ONJ diagnoses were confirmed by adjudication. RESULTS: There were 1340 patients in the DEIC, 1352 in the ZAIC, and 408 in the DESC. The median ages of the 3 cohorts were 70, 69, and 70 years, respectively; the proportions of men were 72.6%, 53.8%, and 48.3%, respectively; and the median follow-up was 19.8, 12.9, and 13.3 months, respectively. The 5-year incidence proportions of ONJ were 5.7% (95% confidence interval [CI], 4.4%-7.3%) in the DEIC, 1.4% (95% CI, 0.8%-2.3%) in the ZAIC, and 6.6% (95% CI, 4.2%-10.0%) in the DESC. The corresponding ONJ incidence rates per 100 person-years were 3.0 (95% CI, 2.3-3.7), 1.0 (95% CI, 0.6-1.5), and 4.3 (95% CI, 2.8-6.3). Incidence proportions and incidence rates were highest in patients with prostate cancer and in Denmark. CONCLUSIONS: This study provides estimates of the risk of medically confirmed ONJ among patients initiating denosumab or zoledronic acid in routine clinical practice in 3 Scandinavian countries. The results varied by cancer site and by country. LAY SUMMARY: Denosumab and zoledronic acid reduce the risk of bone fractures, pain, and surgery in patients with advanced cancers involving bone. Osteonecrosis of the jaw (ONJ)-death of a jawbone-is a known side effect of treatment with denosumab or zoledronic acid. The authors examined almost 2900 denosumab- or zoledronic acid-treated patients with cancer in Denmark, Norway, and Sweden. Over the course of 5 years, ONJ developed in 5.7% of the patients whose initial treatment was denosumab, in 1.4% of the patients whose initial treatment was zoledronic acid, and in 6.6% of the patients who switched from zoledronic acid to denosumab.

Denosumab compared with zoledronic acid on PFS in multiple myeloma: exploratory results of an international phase 3 study.

An exploratory end point from a recent trial in patients with newly diagnosed multiple myeloma showed that median progression-free survival (PFS) was increased by 10.7 months with denosumab vs zoledronic acid. We performed additional analyses to identify factors that may have contributed to the favorable PFS with denosumab. Ad hoc analyses were performed for patients intending to undergo autologous stem cell transplantation (ASCT; ASCT intent), not intending to undergo ASCT (ASCT no intent), and intent-to-treat according to age (<70 or ≥70 years) and baseline renal function (≤60 mL/min or >60 mL/min creatinine clearance [CrCl]). Of 1718 patients, 930 (54.1%) were in the ASCT-intent subgroup, and 788 (45.9%) were in the ASCT-no-intent subgroup. In the ASCT-intent subgroup, frontline triplet (median PFS, not estimable vs 35.7 months; hazard ratio [HR] [95% confidence interval (CI)], 0.65 [0.47-0.90]; descriptive P = .009) or bortezomib-only (median PFS, not estimable vs not estimable; HR [95% CI], 0.61 [0.39-0.95]; descriptive P = .029) induction regimens demonstrated the strongest PFS benefit favoring denosumab vs zoledronic acid. In the ASCT-no-intent subgroup, no benefit with denosumab vs zoledronic acid was observed. PFS favored denosumab vs zoledronic acid in patients with CrCl >60 mL/min and in patients <70 years old, but no difference was observed in patients with CrCl ≤60 mL/min or patients ≥70 years old. The PFS difference observed with denosumab is one of the notable benefits reported in newly diagnosed multiple myeloma and was most pronounced in patients intending to undergo ASCT and those who received proteasome inhibitor (PI)-based triplet regimens. This study was registered at www.clinicaltrials.gov as #NCT01345019.

Denosumab Versus Zoledronic Acid in Bone Disease Treatment of Newly Diagnosed Multiple Myeloma: An International, Double-Blind, Randomized Controlled Phase 3 Study-Asian Subgroup Analysis.

INTRODUCTION: The primary analysis of a global phase 3 study that evaluated the efficacy and safety of denosumab versus zoledronic acid for preventing skeletal-related events (SREs) in adults with newly diagnosed multiple myeloma (MM) indicated that denosumab was noninferior to zoledronic acid for time to first on-study SREs. Here we present a subgroup analysis to evaluate efficacy and safety in Asian patients. METHODS: Patients were randomized 1:1 to receive denosumab 120 mg subcutaneously or zoledronic acid intravenously 4 mg every 4 weeks in a double-blind, double-dummy fashion. All patients received standard-of-care first-line antimyeloma treatment. Each patient received either study drug until an estimated 676 patients experienced at least one on-study SRE and the primary efficacy and safety analyses were completed. RESULTS: Of 1718 total enrolled patients, 196 Asian patients (denosumab, n = 103; zoledronic acid, n = 93) were included in this subgroup analysis. Fewer patients in the denosumab group developed first on-study SRE compared with the zoledronic acid group; the crude incidence of SREs at the primary analysis cutoff was 38.8% and 50.5%, respectively (HR [95% CI], 0.77 [0.48-1.26]). All 194 patients receiving at least one dose of study drug experienced at least one treatment-emergent AE. The most common AEs reported in either group (denosumab, zoledronic acid) were diarrhea (51.0%, 51.1%), nausea (42.2%, 46.7%), and pyrexia (38.2%, 41.3%). Treatment-emergent renal toxicity occurred in 9/102 (8.8%) and 20/92 (21.7%) patients, respectively. Similar rates of positively adjudicated osteonecrosis of the jaw (7 [6.9%] vs 5 [5.4%]) and treatment-emergent hypocalcemia (19 [18.6%] vs 17 [18.5%]) were reported in the denosumab and zoledronic acid groups, respectively. CONCLUSION: Efficacy and safety outcomes from this Asian subgroup were comparable to those of the full study population. Overall, this analysis supports denosumab as an additional treatment option for standard of care for Asian patients with newly diagnosed MM with lytic bone lesions. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT01345019.