Zoledronic Acid Versus Alendronate for Prevention of Bone Loss After Organ Transplantation

The purpose of this study is to compare the effectiveness and safety of zoledronic acid with alendronate in the prevention of bone loss after organ transplantation. Zoledronic acid is given as a single intravenous infusion. Alendronate is given as a weekly pill. Both are expected to be very effective, but it is not known which one will work best.

Patients who have undergone heart or liver transplantation are usually required to remain on medications, such as Prednisone and Cyclosporine A or Tacrolimus, that prevent the body from rejecting the transplanted organ. These medications may cause bone loss which leads to thinning of the bones (osteoporosis) and therefore greatly increase the risk of having broken bones (fractures) after transplantation. Several published studies have shown that 14% to 35% of heart transplant patients develop fractures (spine, ribs and hip) during the first year after transplantation. We have previously shown that alendronate (Fosamax), a drug approved by the FDA for prevention and treatment of postmenopausal osteoporosis and prednisone-induced osteoporosis, prevents bone loss after heart transplantation. We are conducting this study to determine whether a newer drug, zoledronic acid, is as effective as alendronate. This study is a randomized, double-blind, placebo-controlled 2-year study. Participants will receive one dose of active zoledronic acid during the first month after heart or liver transplantation and weekly placebo alendronate pills or one dose of placebo zoledronic acid and weekly active alendronate pills for the first year after transplant. Over 2 years, participants will provide blood samples on nine occasions. Bone density will be performed 4-5 times and spine xrays will be performed twice.