- CONDITION CENTERS
Osteoporosis is a disease of the bones that results in loss of bone mass and structural breakdown of bone tissue, which ultimately leads to bone weakness and an increased risk of fractures. Osteoporosis, or "porous bones," affects ~10 million Americans, of whom 8 million are women. Also, an estimated 34 million Americans have low bone mass, placing them at elevated risk for osteoporosis. 1 The disease is mostly asymptomatic, and diagnosis may not be determined until a sudden incident causes a fracture. Some symptoms associated with osteoporosis include severe back pain or stooped posture.1
Current therapies for the prevention and treatment of osteoporosis include bisphosphonates, estrogen therapy, selective estrogen receptor modulators, calcium, and vitamin D supplementation.1 Roche Laboratories released ibandronate sodium (Boniva) tablets in 2003 for the management of postmenopausal osteoporosis. In January 2006, the FDA approved Boniva for injection, a once-quarterly intravenous injection for the treatment of postmenopausal osteoporosis.
Boniva is a bisphosphonate and works by inhibiting osteoclast activity, which results in a reduction in bone resorption. In postmenopausal women, it reduces bone turnover and may cause an increase in bone mass.2
An early clinical trial examined the safety and efficacy of intravenous ibandronate sodium for the prevention of postmenopausal osteoporosis.The multicenter, randomized, double-blind, placebo-controlled trial included ~630 postmenopausal women. Patients received a dose of either ibandronate 0.5 mg, 1 mg, or 2 mg, or placebo, intravenously every 3 months. The primary outcome was the mean change in bone mineral density (BMD) of the lumbar spine, compared with baseline. Results demonstrated a dose-dependent increase in BMD for the patients receiving active drug therapy. Increase in BMD from baseline for the 0.5-, 1-, and 2-mg groups were standard deviations 1, 1.8, and 2.5, respectively (P = .001). Those receiving placebo therapy had a decrease in BMD of 0.4 (P = .001).3
The Dosing Intravenous Administration (DIVA) study compared 2 different intravenous ibandronate regimens with its oral dosage form. The multicenter, randomized, double-blind, noninferiority trial included ~1400 women and took place over a 2-year period. Treatment groups included intravenous ibandronate 2 mg every 2 months, 3 mg every 3 months, or oral ibandronate 2.5 mg daily. All women received supplemental calcium and vitamin D throughout the trial. DIVA compared the efficacy, safety, and tolerability of the different treatment arms, with the primary end point being the mean change of lumbar spine BMD from baseline at 1 year, with a noninferiority margin of 1%. Results after 1 year of therapy demonstrated an increased percentage change in lumbar spine BMD from baseline in the 2-and 3-mg injection groups versus oral therapy (3.8%, 5.1%, and 4.8%, respectively, P = .001). Two-year findings included increased lumbar BMD more so with the intravenous dosing groups than the oral dosing group6.4% and 6.3% with 2 and 3 mg, respectively, and 4.8% with oral ibandronate (P <.001).4
The most common adverse events with ibandronate include arthralgia, back pain, abdominal pain, hypertension, and influenza-like symptoms.2 Intravenous ibandronate is eliminated renally and therefore should not be given to any patient with a creatinine clearance less than 30 mL/min. No dose adjustments are necessary in patients with hepatic impairment. Hypocalcemia and hypovitaminosis D must be treated prior to starting ibandronate injection, and it is recommended to continue supplementation during therapy.2 Ibandronate is in pregnancy category C and should only be used in pregnancy only if the potential benefit outweighs the risk to the fetus.
Boniva injection can be used to treat osteoporosis in postmenopausal women who may have compliance problems with their current oral regimen. The recommended dose of Boniva injection is 3 mg every 3 months administered over a period of 15 to 30 seconds and must be administered by a health care professional.2
Dr. Soo is a senior research pharmacist with the Investigational Drug Service at Brigham and Women's Hospital, Boston, Mass. Nolan Cook is a sixth-year PharmD candidate from Massachusetts College of Pharmacy currently on clinical clerkship in the Investigational Drug Service at Brigham and Women's Hospital.
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