Impact of Extended-Interval Versus Standard Dosing of Zoledronic Acid on Skeletal Events in Non-Small-Cell Lung Cancer and Small-Cell Lung Cancer Patients With Bone Metastases.

Background: Zoledronic acid every 4 weeks (Q4wk) reduces the incidence of skeletal-related events (SREs) in patients with metastatic lung cancer. Lung cancer patients were excluded from extended-interval dosing trials (every 12 weeks [Q12wk]) that demonstrated noninferiority of the 2 dosing schemes. To date, the optimal dosing of zoledronic acid in metastatic lung cancer remains unknown.

Objective: To determine whether zoledronic acid dosed Q12wk is similar to Q4wk dosing for prevention of SRE in patients with metastatic lung cancer.

Methods: A retrospective analysis was performed in patients with non-small-cell lung cancer and small-cell lung cancer with bone metastases who received Q12wk and Q4wk zoledronic acid. The primary outcome was incidence of SRE at 1 year. Secondary analyses included time to first SRE, overall survival (OS), incidence of osteonecrosis of the jaw (ONJ), kidney dysfunction, and hypocalcemia.

Results: A total of 34 patients received Q12wk and 46 patients received Q4wk zoledronic acid. Incidence of SRE at 1 year (Q12wk, 23.5%, vs Q4wk, 23.9%; 95% CI = -0.184 to 0.192; = 0.968) and median time to SRE (not reached for either cohort; = 0.530) did not differ. The Q12wk cohort had longer median OS (24.00 vs 8.97 months; = 0.022). There were no differences in incidence of ONJ, kidney dysfunction, and hypocalcemia.

Conclusion And Relevance: This is the first report examining extended-interval dosing of zoledronic acid in metastatic lung cancer. Incidence and time to SRE at 1 year were similar. This extended-interval dosing may be safe and reasonable for patients with lung cancer with bone metastases.