Patients with bone metastases from solid tumors initiating treatment with a bone-targeted agent in 2011: a...

Three bone-targeted agents (BTAs) are approved in the USA for prevention of bone complications among solid tumor patients with bone metastases: two intravenous bisphosphonates (IV BP) (pamidronate and zoledronic acid), and one subcutaneous receptor activator of nuclear factor-kappaB (RANK) ligand inhibitor (denosumab). Using electronic medical record data from outpatient community and hospital-affiliated oncology clinics, we examined the characteristics of patients who initiated treatment with a BTA in 2011 and followed them for a maximum of 12 months.

Adult patients with bone metastasis secondary to solid tumors newly treated with a BTA during 2011 were identified from the Oncology Services Comprehensive Electronic Records (OSCER) database. We examined patient characteristics at BTA initiation, treatment patterns, and compliance during a 12-month period. Sensitivity analyses were performed in a subgroup of patients who had confirmed 12 months of follow-up data.

Denosumab patients (N = 1,594) were older (65 % ≥65 years vs. 60 % ≥65 years), further along in their disease progression (time since bone metastasis diagnosis: 16 % ≥2 years vs. 10 % ≥2 years), less likely to switch BTA (overall: 6 vs. 14 %; subgroup: 8 vs. 19 %), and more compliant with treatment (overall: median doses of 7 vs. 4; subgroup: 11 vs. 8) compared to IV BP patients (N = 1,975). Findings were consistent across gender, age, tumor type, naïve, and transition strata.

Patients receiving denosumab and IV BPs may differ. Despite higher age and more advanced disease, patients treated with denosumab are more likely to stay on treatment and have better compliance.