The effects of zoledronic acid on serum lipids in multiple myeloma patients

Nitrogen-containing bisphosphonates (N-BPs) inhibit osteoclast-mediated bone resorption and are widely used for tumor-associated osteolysis. The mechanism of action of these drugs has not been completely clarified, but it has been observed that N-BPs may inhibit squalene synthase or farnesyl pyrophosphate synthase. Zoledronic acid (ZA) represents a novel N-BP which also has antitumor activity. To explore the effects of ZA on serum lipids, we studied 26 patients with smoldering myeloma at diagnosis. Sixteen patients were treated with ZA (4 mg) at baseline and at months 1, 2, 4, and 6. The remaining 10 served as controls. In all subjects, total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and C-terminal telopeptide of type I collagen (CTX) were measured at baseline and after 1, 3, and 6 months. In treated patients, we observed a progressive and significant reduction of TC, with a maximum decrease of 13% at 6 months. Moreover LDL-C decreased by 21% at 6 months, while no significant difference was appreciated in HDL-C and TGs. Also, the indexes of cardiovascular risk improved after ZA administration: TC/HDL-C ratio progressively decreased by 17% and HDL-C/LDL-C ratio increased by 36%, showing an effect that appears to be cumulative. In conclusion, ZA given intravenously at high doses in patients with smoldering myeloma seems to be able to modify the lipid profile with an improvement of atherosclerotic risk index.