Prolonged Use of Zoledronic Acid (4 Years) Did Not Improve Outcome in Multiple Myeloma Patients

To assess whether prolonged use of zoledronic acid (ZA; 4 years) improves outcome in multiple myeloma patients, we performed a clinical trial to compare the effect of 48 and 24 months of treatment. A total of 170 patients were randomly assigned to the 2 groups in the trial. Overall survival was not improved, however, the ZA group showed a reduced number of skeletal events. Thus, we suggest that ZA should be considered to be used for longer duration, in an attempt to improve patient quality of life. Background: Bisphosphonates, especially zoledronic acid (ZA), show antitumor effects in multiple myeloma (MM) and other neoplasms. The standard time for ZA administration has been 2 years. However, with improvement in overall survival (OS) in MM with new agents, it unclear whether ZA could be administered for a prolonged time to improve OS. Patients and Methods: A total of 170 patients with untreated, symptomatic MM were randomly divided into a group to receive ZA for 4 years, with a control group to receive ZA for 2 years. All patients were treated with the same induction therapy and stem-cell transplantation. Results: Actuarial curves at 5 years, showed that progression-free survival was 75% (95% confidence interval [CI], 64%-82%) and OS was 68% (95% CI, 60%-76%) in the 4-year group, which was not statistically significantly different compared with the control group: 72% (95% CI, 62%-78%) and 68% (95% CI, 60%-75%; P = .67). However, the 4-year group showed reduced skeletal events (21% occurrence rate); this was statistically significant compared with the control group: 43% (P < .001). Conclusion: Although ZA did not improve OS in patients with MM; it continued to be useful to reduce skeletal events, and thus improve better quality of life for patients.