VIENNA — A single 5-mg IV infusion of zoledronic acid produces significantly greater therapeutic efficacy and a longer-lasting biochemical remission than 2 full months of oral risedronate at 30 mg/day in patients with Paget's disease of bone, Jacques P. Brown, M.D., reported at the annual European congress of rheumatology.
Zoledronic acid (Zometa) is clearly the clinically advantageous drug, both in bisphosphonate-naive patients and in those previously on risedronate (Actonel) or other oral bisphosphonates, added Dr. Brown of the Centre Hospitalier Universitaire de Québec, Sainte-Foy.
At the meeting, sponsored by the European League Against Rheumatism, he presented a pooled analysis combining the data from two randomized, double-blind, multicenter trials of 349 patients with Paget's disease of bone. Participants received a single 15-minute 5-mg infusion of zoledronic acid or 30 mg/day of oral risedronate for 2 months.
The primary end point was a reduction of 75% or more in excess serum alkaline phosphatase (SAP) at 6 months. Ninety-six percent of patients in the zoledronic acid group achieved it vs. 74% in the risedronate arm. Eighty-nine percent of zoledronic acid-treated patients achieved normalization of SAP at the 6-month mark, compared with 58% on risedronate.
The therapeutic response to zoledronic acid was significantly swifter and longer lasting than the response to risedronate. At the 1-month mark, 20% of the zoledronic acid group had achieved at least a 75% reduction in excess SAP, while just 1% of the risedronate group did. At 2 months, 90% of zoledronic acid-treated patients showed a therapeutic response vs. 47% on risedronate. Moreover, only 2 patients in the zoledronic acid group lost their therapeutic response between months 6 and 18, while 36 in the risedronate group did.
One hundred percent of patients randomized to zoledronic acid after having previously been on an oral bisphosphonate had a therapeutic response to the intravenous third-generation bisphosphonate. In contrast, only 30% of patients previously on risedronate or another oral bisphosphonate achieved a therapeutic response when randomized to risedronate in the study.
Side effects of zoledronic acid include myalgia, fatigue, headache, rigors, nausea, and bone pain. In these studies, the effects were mild to moderate in nature, often began within 3 days after the first dose, and typically lasted less than 4 days.
The studies were funded by Novartis Pharmaceuticals.