Upfront Zoledronic Acid Research Articles

Efficacy of zoledronic acid in postmenopausal Japanese women with early breast cancer receiving adjuvant letrozole: 36-month results.

e20510 Background: We reported 12-month results of upfront zoledronic acid (ZOL) therapy, which prevented bone loss in postmenopausal Japanese women who were receiving adjuvant letrozole, confirming the Z-FAST and ZO-FAST studies results. But the examination in the long term of aromatase inhibitor-associated bone loss has not been proved in the Japanese or Asia women. Methods: Postmenopausal women with hormone receptor positive early breast cancer (BC) patients receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start ZOL (4mg intravenously every 6 months) for 5 years. The delayed group received ZOL when lumbar spine (L2-L4) BMD decreased to less than young adult mean (YAM) – 2.0 S.D or when a nontraumatic fractured occurred. The primary endpoint of this study was to compare the changes in L1-L4 BMD at month 12 between the groups. Secondary endpoints, measured at other predetermined timepoints, included comparing changes in L1-L4, L2-L4and total hip (TH) BMD and markers of bone turnover, fracture incidence, and time to disease recurrence. We report the results of 36-month interim analysis. Results: At 36 months, mean change in L1-L4 BMD was 10.7% higher in the upfront group than in the delayed group ( 95% CI, 9.2% to 12.1%; p< 0.001 ), L2-L4BMD was 10.9% higher ( 95% CI, 9.3% to 12.5%; p< 0.001 ), and TH BMD was 6.7% higher ( 95% CI, 5.3% to 8.1%; p< 0.001 ). The incidence of fracture was not significantly different between each group (upfront, 1(1.0%) vs. delayed, 4(4.1%)). Disease recurrence was reported in 3 upfront (3.1%) and 1 delayed (1.0%) patients. By month 36, 11 patients (11.3%) in the delayed group initiated ZOL therapy. There was no significant difference of adverse events other than fever with ZOL at the first treatment between the two groups. Conclusions: Upfront ZOL seems to be the preferred treatment strategy versus delayed administration, as it significantly and progressively increases BMD in postmenopausal Japanese women with early BC who were receiving adjuvant letrozole for 36 months. Clinical trial information: UMIN000001104.

Efficacy of zoledronic acid in postmenopausal Japanese women with early breast cancer receiving adjuvant letrozole: 12-month results

Aromatase inhibitor-associated bone loss has not been proved in the Japanese or Asian women. The aim of this study was to evaluate an upfront or delayed strategy of bone protection therapy with zoledronic acid administered at 4 mg every 6 months in postmenopausal Japanese women with early breast cancer to compare with results of the Z-FAST and ZO-FAST studies in western countries. Postmenopausal women with hormone receptor positive early breast cancer receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months). The delayed group received zoledronic acid when lumbar spine (L(2)-L(4)) bone mineral density (BMD) decreased to less than young adult mean -2.0SD or when a nontraumatic fracture occurred. The primary endpoint of this study was to compare the percent change in L(1)-L(4) BMD at 12 months between the groups. Secondary endpoints included percent changes in L(2)-L(4) and total hip (TH) BMD. The upfront and delayed groups included 94 and 95 patients, respectively. At 12 months, L(1)-L(4), L(2)-L(4), and TH BMD significantly decreased by 2.0, 2.4, and 2.4%, respectively, in the delayed group. L(1)-L(4) BMD was 4.9% higher in the upfront group than in the delayed group (95% CI 3.9-5.8%; p < 0.001). L(2)-L(4) BMD was 5.6% higher (95% CI 4.5-6.6%; p < 0.001), and TH BMD was 4.4% higher (95% CI 3.3-5.4%; p < 0.001). At 12 months, upfront zoledronic acid therapy prevented bone loss in postmenopausal Japanese women who were receiving adjuvant letrozole, confirming the Z-/ZO-FAST study results in western populations.

Final 5‐year results of Z‐FAST trial

Postmenopausal breast cancer (BC) patients receiving adjuvant aromatase inhibitor therapy are at risk of progressive bone loss and fractures. Zoledronic acid inhibits osteoclastic bone resorption, is effective in maintaining bone health, and may therefore be beneficial in this setting. Overall, 602 postmenopausal women with early, hormone receptor-positive BC receiving adjuvant letrozole were randomized (301 each group) to receive upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months) for 5 years. The primary endpoint was the change in lumbar spine (LS) bone mineral density (BMD) at month 12. Secondary endpoints included changes in LS BMD, total hip BMD, and bone turnover markers at 2, 3, and 5 years; fracture incidence at 3 years; and time to disease recurrence. At month 61, the adjusted mean difference in LS and total hip BMDs between the upfront and delayed groups was 8.9% and 6.7%, respectively (P < .0001, for both). Approximately 25% of delayed patients received zoledronic acid by month 61. Only 1 patient experienced grade 4 renal dysfunction; no confirmed cases of osteonecrosis of the jaw were reported. Fracture rates (upfront, 28 [9.3%]; delayed, 33 [11%]; P = .3803) and Kaplan-Meier disease recurrence rates (upfront, 9.8 [95% confidence interval (CI), 6.0-10.3]; delayed, 10.5 [95% CI, 6.6-14.4]; P = .6283) were similar at month 61. Upfront zoledronic acid seems to be the preferred treatment strategy versus delayed administration, as it significantly and progressively increases BMD in postmenopausal women with early BC receiving letrozole for 5 years, and long-term coadministration of letrozole and zoledronic acid is well tolerated.

Immediate versus delayed zoledronic acid for prevention of bone loss in postmenopausal women with breast cancer starting letrozole after tamoxifen-N03CC

Postmenopausal women with breast cancer (BC) are at increased risk for bone loss. Bisphosphonates improve bone mineral density (BMD) in normal postmenopausal women. The purpose of this study was to determine if immediate treatment with zoledronic acid preserves BMD in postmenopausal women with BC starting letrozole after tamoxifen. Postmenopausal women with BC completing tamoxifen were treated with daily letrozole 2.5 mg/vitamin D 400 I.U., calcium 500 mg twice daily and were randomized to upfront or delayed zoledronic acid 4 mg every 6 months. Patients in the delayed arm were only given zoledronic acid if they developed a post-baseline BMD T score <-2.0 or had a fracture. The primary endpoint was the mean percent change in lumbar spine (LS) BMD at 1 year. About 558 women enrolled; 395 provided 1 year BMD data. The upfront arm experienced a mean change of +3.66% in LS BMD versus -1.66% for the delayed group (P < 0.001). Changes at the femoral neck/total hip were also greater for the upfront versus delayed arms (P < 0.001; P < 0.001) with differences persisting at 2 years. Patients in the delayed arm were more likely to experience a clinically meaningful 5% loss of BMD at all sites versus the upfront zoledronate group. Patients in the upfront arm were slightly more likely to report limb edema, fatigue, fever, nausea and jaw osteonecrosis(1%). Upfront zoledronic acid prevents bone loss in postmenopausal women with BC starting letrozole after tamoxifen.

Integrated Analysis of Zoledronic Acid for Prevention of Aromatase Inhibitor–Associated Bone Loss in Postmenopausal Women with Early Breast Cancer Receiving Adjuvant Letrozole

The interim (12-month) results of two similarly designed, ongoing studies (the Zometa-Femara Adjuvant Synergy Trials [Z-FAST and ZO-FAST]) suggest that zoledronic acid (4 mg intravenously every 6 months) when initiated with adjuvant letrozole increases bone mineral density (BMD) of the lumbar spine (LS) in postmenopausal women with early-stage breast cancer compared with patients who receive zoledronic acid only when bone loss became clinically significant or a fragility fracture occurred. An integrated analysis was performed to maximize the value of the large pool of data from the two studies in answering clinically relevant questions. The primary objective was to compare the change in LS BMD at month 12. Secondary objectives included comparing (a) the change in total hip (TH) BMD, (b) changes in bone turnover marker concentrations, (c) time to disease recurrence, and (d) safety at month 12. The integrated analysis included 1,667 patients. At month 12, LS BMD was 5.2% higher in the upfront group than in the delayed group; TH BMD was 3.5% higher. N-telopeptide and bone-specific alkaline phosphatase concentrations decreased by 21.3% and 12.8% in the upfront group and increased by 21.7% and 24.9% in the delayed group, respectively (p < .0001 for intergroup comparisons). Fewer patients receiving upfront zoledronic acid experienced disease recurrence than patients in the delayed group-seven patients (0.84%) versus 17 patients (1.9%) (p = .0401). Fracture rates were similar. No confirmed osteonecrosis of the jaw was reported. The results of this analysis strengthen the statistical validity of the preliminary results of the Z-FAST and ZO-FAST studies, showing that upfront zoledronic acid prevents aromatase inhibitor-associated bone loss more effectively than delayed-start zoledronic acid in postmenopausal women with early-stage breast cancer receiving letrozole. Additionally, disease recurrence appears to be lower with upfront zoledronic acid, but further follow-up is needed to confirm these interim results.

Reducing the Risk of Cancer Treatment-Associated Bone Loss in Patients With Breast Cancer

Women with breast cancer, especially those receiving aromatase inhibitors, are at higher risk for bone loss and fracture. Postmenopausal women may already have multiple risk factors for fracture, and breast cancer therapies compound these risks. Current guidelines for bone health management in women with breast cancer are based on bone mineral density (BMD) measurements; however, many risk factors for fracture are independent of bone mineral density. Thus, consideration of other risk factors for fracture, including cancer therapies, aromatase inhibitor therapy, and age, may be necessary to accurately identify patients at high risk for bone loss. Bisphosphonates, inhibitors of osteoclast-mediated osteolysis, may be efficacious for the prevention of aromatase inhibitor-associated bone loss. Several clinical trials evaluating zoledronic acid in this setting have produced favorable results. In the Austrian Breast and Colorectal Cancer Study Group (ABCSG)-12 trial, patients receiving anastrozole or tamoxifen plus goserelin experienced significant bone loss, and zoledronic acid treatment prevented bone loss in both groups. Results from the parallel studies Z-FAST, ZO-FAST, and E-ZO-FAST indicate that upfront zoledronic acid treatment increases BMD in patients receiving letrozole. These preliminary results are encouraging and suggest that zoledronic acid is an effective preventative therapy for bone loss in breast cancer patients receiving aromatase inhibitors.

Zoledronic Acid Inhibits Adjuvant Letrozole–Induced Bone Loss in Postmenopausal Women With Early Breast Cancer

Treatment with aromatase inhibitors decreases bone mineral density (BMD) and may increase the risk of fractures in postmenopausal women with early-stage breast cancer. The addition of zoledronic acid to adjuvant letrozole therapy may protect against bone loss. Patients receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months). The delayed group received zoledronic acid when lumbar spine (LS) or total hip (TH) T score decreased to less than -2.0 or when a nontraumatic fracture occurred. The primary end point of this study was to compare the change in LS BMD at month 12 between the groups. Secondary end points included change in TH BMD and changes in serum bone turnover markers at month 12. The upfront and delayed groups each included 301 patients. At month 12, LS BMD was 4.4% higher in the upfront group than in the delayed group (95% CI, 3.7% to 5.0%; P < .0001), and TH BMD was 3.3% higher (95% CI, 2.8% to 3.8%; P < .0001). In the upfront group, mean serum N-telopeptide and bone-specific alkaline phosphatase concentrations decreased by 15.1% (P < .0001) and 8.8% (P = .0006), respectively, at month 12, whereas concentrations increased significantly in the delayed group by 19.9% (P = .013) and 24.3% (P < .0001), respectively. With 1 year of follow-up, results of the primary end point of the Zometa-Femara Adjuvant Synergy Trial (Z-FAST) indicate that upfront zoledronic acid therapy prevents bone loss in the LS in postmenopausal women receiving adjuvant letrozole for early-stage breast cancer.

Management of Cancer-Treatment–Induced Bone Loss in Postmenopausal Women Undergoing Adjuvant Breast Cancer Therapy: A Z-FAST Update

The prevention of cancer-treatment-induced bone loss (CTIBL) in long-term adjuvant breast cancer therapy is a high priority. Postmenopausal women with cancer, already at increased risk of bone loss because of age-related estrogen deficiency, face accelerated bone loss with the use of estrogen-depleting therapies such as third-generation aromatase inhibitors (AIs). Although effective in reducing cancer recurrence rates in the adjuvant setting, AIs are associated with bone loss and an increased risk of fractures. Bisphosphonates, which act by inhibiting osteoclastic bone resorption, have been shown to increase bone mineral density (BMD) and reduce fracture risk in postmenopausal women with established osteoporosis. Furthermore, the potent bisphosphonate zoledronic acid has been shown to be efficacious in reducing bone loss in premenopausal women receiving combination adjuvant hormone therapy (goserelin, a gonadotropin-releasing hormone agonist, plus either an AI or tamoxifen). The use of zoledronic acid to prevent CTIBL in postmenopausal women receiving adjuvant AI therapy with letrozole is currently being investigated in the Zometa/Femara Adjuvant Synergy Trial (Z-FAST). Postmenopausal women with stage I-IIIa estrogen-receptor-positive and/or progesterone-receptor-positive breast cancer starting letrozole are randomized to receive either upfront zoledronic acid or delayed zoledronic acid. At 6 months, assessable women in the upfront group showed a mean increase of 1.55% in lumbar spine (L1 - L4) BMD, compared with a mean decrease of 1.78% in women in the delayed group, resulting in a difference of 3.33% between groups; moreover, women in the former group showed a mean increase of 1.02% in total hip BMD, compared with a mean decrease of 1.40% in those in the latter group, resulting in a significant difference of 2.42% between groups (P <.001). Thus, the Z-FAST BMD results show that upfront zoledronic acid prevents CTIBL in postmenopausal women receiving adjuvant letrozole therapy for early breast cancer. Combining the anticancer efficacy of letrozole with the bone-protective effect of zoledronic acid may be a successful treatment in this setting.