Source: DGNews  |  Posted 5 years ago

By Paula Moyer

NICE, FRANCE -- March 27, 2006 -- Patients with metastatic bone disease due to breast cancer may respond equally well to oral ibandronate (Boniva) as they do to IV zoledronic acid (Zometa), according to research presented here at the 5[^]th[] European Breast Cancer Conference (EBCC).

"A daily dose of 50 mg per day of oral ibandronate produces the same results as IV zoledronic acid for reducing tumour-induced bone resorption, but it is associated with fewer adverse effects," said principal investigator Jean-Jacque Body, MD, PhD, professor of internal medicine, Institut Jules Bordet, Free University of Brussels, Brussels, Belgium.

The tolerability profile of oral ibandronate may provide another option for treating metastatic bone disease in breast cancer, he said in a presentation on March 23[^]rd[].

Both ibandronate and zoledronic acid are approved for the treatment of metastatic bone pain. Previous phase 3 trials showed both formulations to be similar in their ability to reduce skeletal events and in their tolerability profiles, which were comparable with placebo.

In the current research, a head-to-head, open-label, phase 3 trial, investigators compared oral ibandronate and IV zoledronic acid regarding both their effects on bone turnover markers and their safety profiles. The study period was 12 weeks.

The investigators recruited 254 patients with advanced breast cancer and confirmed bone lesions. Within this group, 128 received either oral ibandronate at a dose of 50 mg daily, and 126 received 4 mg of IV zoledronic acid every 4 weeks.

At the study's end, the investigators observed change in serum cross-linked C-terminal telopeptide of type I collagen (S-CTX), a key marker of bone turnover. Other assessments included levels of urinary calcium, bone-specific alkaline phosphatase, amino-terminal procollagen propeptides of type I collagen, and osteocalcin. The investigators also recorded all adverse events.

Oral ibandronate produced reductions in bone marker levels that were comparable with those seen with IV zoledronic acid, the investigators reported.

The percentage of patients with elevated baseline S-CTX levels that were reduced to normal or low levels at the end of the treatment period was 100% in the ibandronate group and 86.4% in the zoledronic acid group.

In the group overall, 65% of those on ibandronate and 76% of those on zoledronic acid experienced adverse events. Within the first 3 days of the study, 8% of those on zoledronic acid and 4% of those on ibandronate had fever or flu-like illness. Other common adverse events with zoledronic acid were bone and joint pain; gastrointestinal discomforts such as nausea, vomiting, and diarrhoea; and injection site problems such as swelling and redness. Other common adverse events with ibandronate were dyspepsia and other gastrointestinal problems such as nausea, diarrhoea, and abdominal pain.

The investigators concluded that the 2 bisphosphonates may be similar in their ability to prevent skeletal-related events, but that oral ibandronate may be better tolerated.

The study included an investigator from Hoffman La Roche. Boniva is manufactured by Roche and marketed by Roche and GlaxoSmithKline. Zometa is manufactured by Novartis.

[Presentation title: Phase III Trial of Oral Ibandronate and IV Zoledronic Acid in Breast Cancer Patients With Bone Metastases: Comparative Bone Turnover Marker and Safety Data. Abstract 398]