Persistence of denosumab in Slovak patients with bone metastases - a prospective observational study.

Abstract

Background: An integrated analysis of phase III trials in patients with advanced solid tumors demonstrated superiority of denosumab over zoledronic acid in preventing skeletal-related events. A drug's clinical efficacy, however, depends on regular and continued administration (persistence); persistence in Slovak real-life is yet undetermined for denosumab in the oncology indication.

Patients and methods: This was a single-arm, prospective, observational, non-interventional study in patients with bone metastases from solid tumors treated with denosumab every 4 weeks in real-world clinical practice in 5 European countries. The results of the 54 patients from Slovakia are presented here. Persistence was defined as denosumab administration at ≤ 35-day intervals over 24 or 48 weeks, respectively.

Results: Previous skeletal-related events were found in 5.6% of patients. 84.8% were persistent over 24 weeks and 61.4 % over 48 weeks. The median (95% confidence interval (CI)) time to non-persistence was 306.5 days (Q1 = 151.0; Q3 = 315.0). The most frequent reason for non-persistence was delayed administration of denosumab. There was a trend towards weaker analgesics over time, with > 70% of patients not requiring any analgesics. Serum calcium remained within the normal range throughout the whole study. Adjudicated osteonecrosis of the jaw was not documented in any Slovak patient.

Conclusion: Most patients received denosumab regularly once every 4 weeks over 24 weeks of treatment. Non-persistence was mainly due to delayed administration. The incidence of adverse drug reactions was in line with expectations from previous studies, osteonecrosis of the jaw did not occur in any of the patients involved in the study.