Nicholas Sauter

Efficacy and safety of continued zoledronic acid every 4 weeks versus every 12 weeks in women with bone metastases from breast cancer: Results of the OPTIMIZE-2 trial.

LBA9500^ Background: Zoledronic acid (ZOL, 4 mg) every (q) 4 wk reduces the risk of skeletal-related events (SREs) in patients (pts) with bone metastases from breast cancer (BC). The OPTIMIZE-2 trial examined whether ZOL q12 wk was non-inferior to ZOL q4 wk in pts who had previously received monthly IV bisphosphonate (BP) therapy for ~1 year or longer. METHODS This was a prospective, randomized, double-blind, multicenter trial in female pts with bone metastases from BC who previously received ≥9 doses of IV BP (ZOL or pamidronate) during the first 10-15 months of therapy. Pts were randomized (1:1) to receive ZOL 4 mg IV q4 wk or q12 wk (placebo between ZOL doses to maintain blind) for 1 year. The primary endpoint was the proportion of pts with ≥1 SRE on study (SRE rate). Primary analysis was non-inferiority (pre-defined margin of 10%) for the difference in SRE rates. Secondary endpoints included time to first SRE, skeletal morbidity rate (SMR), bone pain score, change in bone turnover markers, and safety. RESULTS 403 pts were randomized to ZOL q4 wk (n = 200) or q12 wk (n = 203). Median age was 59 years, and baseline characteristics were similar between arms. The SRE rate was 22% and 23.2% in the ZOL q4 and q12 wk arms, respectively. The difference in SRE rate between arms was 1.2% (95% CI, -7.5% to 9.8%; P = .724). The upper limit of this 95% CI (9.8%) is less than the predefined margin of 10%, which indicates non-inferiority of ZOL q12 wk vs q4 wk. Times to first on-study SRE (HR, 1.06; 95% CI, 0.70 to 1.60; P = .792) were similar in the ZOL q4 and q12 wk arms, and mean SMRs were also similar (0.46 vs 0.50, respectively; P = .854). Overall, changes from baseline in bone turnover markers, and the incidence of treatment-emergent adverse events (TEAEs), were similar in the 2 arms. Numerically more renal TEAEs were reported in the ZOL q4 wk vs q12 wk arm (9.6% vs 7.9%, respectively). Two cases (1.0%) of osteonecrosis of the jaw (ONJ) were reported in the q4 wk arm. CONCLUSIONS Among pts who had received monthly IV BP therapy for 1 year or longer, the efficacy of continuing ZOL for an additional year at q12 wk was non-inferior to ZOL q4 wk. Fewer renal AEs and none of the ONJ events were observed in the ZOL q12 wk vs ZOL q4 wk arm. CLINICAL TRIAL INFORMATION NCT00320710.

Continued treatment effect of zoledronic acid dosing every 12 vs 4 weeks in women with breast cancer metastatic to bone: The OPTIMIZE-2 randomized clinical trial

Importance Zoledronic acid, a potent bisphosphonate, is commonly administered to patients with bone metastases to reduce the risk of skeletal-related events (SREs). However, there have been concerns regarding its long-term monthly administration. Objective To examine whether zoledronic acid every 12 weeks was noninferior to zoledronic acid every 4 weeks in patients with metastatic breast cancer that involved the bone who had previously received a standard dosing regimen of zoledronic acid and/or pamidronate disodium. Design, Setting, and Participants OPTIMIZE-2 was a prospective, randomized, double-blind, multicenter phase 3 trial of intention-to-treat (full analysis set), evaluable (per protocol), and safety populations. Patients were randomized (1:1) to receive 4.0 mg of intravenous zoledronic acid every 4 or every 12 weeks with placebo for interim infusions for 1 year. The study was conducted at 102 clinical trial centers in the United States from March 3, 2006, to July 25, 2013. Data analysis was performed from October 7, 2013, to March 24, 2014. The study randomized 416 women (≥18 years old) with bone metastases from breast cancer who previously received 9 or more doses of zoledronic acid and/or pamidronate during the first 10 to 15 months of therapy. Main Outcomes and Measures The primary end point was the proportion of patients with 1 or more SRE on study (SRE rate). The key secondary end points included time to first SRE and skeletal morbidity rate (SMR). Results A total of 416 women were randomized: 200 patients received zoledronic acid every 4 weeks (mean [SD] age, 59.2 [11.1] years; 173 were white [86.5%]), 203 patients received zoledronic acid every 12 weeks (mean [SD] age, 58.6 [11.2] years; 178 were white [87.7%]), and 13 patients received placebo (mean [SD] age, 60.8 [12.2] years; 13 were white [100%]). Baseline characteristics were similar in both zoledronic acid treatment arms. After 1 year of follow-up, SREs occurred in 44 patients (22.0%) in the zoledronic acid every 4 weeks group and 47 patients (23.2%) in the zoledronic acid every 12 weeks group (proportional difference of −1.2%; 1-sided 97.5% CI bound of the difference in SRE rate between arms, −9.8%; noninferiority P = .02). The time to first SRE between treatment groups was not statistically significantly different (hazard ratio [HR], 1.06; 95% CI, 0.70-1.60; P = .79). The mean (SD) SMR was 0.46 (1.06) vs 0.50 (1.50) events per year in the every 4 weeks vs every 12 weeks groups (P = .85). The safety profiles of the every 4 weeks and every 12 weeks groups were comparable, with 189 patients (95.5%) in the every 4 weeks group having at least 1 adverse event compared with 189 (93.5%) in the every 12 weeks group. Conclusions and Relevance The every 12 weeks regimen of zoledronic acid was noninferior to the every 4 weeks regimen for the proportion of patients experiencing 1 or more SRE. These results may have a substantial influence on current clinical practice for treatment of patients with bone metastasis from breast cancer. Trial Registration clinicaltrials.gov Identifier: NCT00320710