Three-monthly Ibandronate Bolus Injection Offers Favourable Tolerability and Sustained Efficacy Advantage over Two Years in Established Corticosteroid-induced Osteoporosis

Objective: Corticosteroids are widely prescribed, although treatment-related side-effects are common. Of these adverse events (AEs), osteoporosis is considered the most serious. Currently, oral bisphosphonates are the standard treatment for corticosteroid-induced osteoporosis (CIO). However, intermittent intravenous (i.v.) therapy may have advantages, including lack of gastrointestinal AEs, improved bioavailability and increased compliance. This study investigated the efficacy and safety of 3-monthly i.v. ibandronate bolus injections in patients with established CIO. The results from a planned 2-yr interim analysis are reported.

Method: In this controlled, prospective, open-label, parallel-group study, 104 patients (49 men and 55 women) with established CIO (mean T-score <-2.5 s.d. at the lumbar spine (L2-L4) received daily calcium (500 mg) plus either 3-monthly i.v. ibandronate (2 mg) bolus injections or oral daily alfacalcidol (1 micro g). The primary end-point was bone mineral density (BMD) change at the lumbar spine, femoral neck and calcaneus after 24 months.

Results: Compared with oral daily alfacalcidol, i.v. ibandronate produced significantly superior gains in mean (+/-s.d.) BMD at the lumbar spine (2.2+/-3.1 vs 11.9+/-7.4%; P<0.001), femoral neck (1.3+/-1.8 vs 4.7+/-4.0%; P<0.001) and calcaneus (7.6+/-3.8 vs 15.5+/-10.7%; P<0.0001) after 2 yr. Consistent with these BMD gains and, although the study was not powered for fractures, a trend towards a reduction in vertebral fractures and greater back pain relief was seen in the ibandronate group. The overall incidence of AEs was similar in the two treatment arms.

Conclusions: Three-monthly i.v. ibandronate bolus injections are significantly superior to alfacalcidol in the treatment of CIO. These data confirm the potential of ibandronate for the treatment of osteoporosis associated with corticosteroid use. The ease of administration, lack of AEs and good compliance associated with intermittent i.v. ibandronate make it a potentially valuable alternative to oral bisphosphonate therapy for the treatment of CIO.