Bisphosphonates and metastatic bone disease

Current comprehensive understanding of denosumab (the RANKL neutralizing antibody) in the treatment of bone metastasis of malignant tumors, including pharmacological mechanism and clinical trials

Denosumab, a fully humanized monoclonal neutralizing antibody, inhibits activation of the RANK/RANKL/OPG signaling pathway through competitive binding with RANKL, thereby inhibiting osteoclast-mediated bone resorption. Denosumab inhibits bone loss; therefore, it is used to treat metabolic bone diseases (including postmenopausal osteoporosis, male osteoporosis, and glucocorticoid-induced osteoporosis), in clinical practice. Since then, multiple effects of denosumab have been discovered. A growing body of evidence suggests that denosumab has a variety of pharmacological activities and broad potential in clinical diseases such as osteoarthritis, bone tumors, and other autoimmune diseases. Currently, Denosumab is emerging as a treatment for patients with malignancy bone metastases, and it also shows direct or indirect anti-tumor effects in preclinical models and clinical applications. However, as an innovative drug, its clinical use for bone metastasis of malignant tumors is still insufficient, and its mechanism of action needs to be further investigated. This review systematically summarizes the pharmacological mechanism of action of denosumab and the current understanding and clinical practice of the use of denosumab for bone metastasis of malignant tumors to help clinicians and researchers deepen their understanding of denosumab.

Bisphosphonate-related osteonecrosis of the jaw: a review of the literature

Bisphosphonates (BPs) are a class of drugs used to treat osteoporosis and malignant bone metastasis. BPs show high binding capacity to the bone matrix, especially in sites of active bone metabolism. The American Society for Bone and Mineral Research defines BRONJ as “an area of exposed bone in the maxillofacial region that has not healed within 8 weeks after identification by a healthcare provider in a patient who is receiving or has been exposed to a bisphosphonate and has not had radiation therapy to the craniofacial region.” Bisphosphonate-related osteonecrosis of the jaw (BRONJ) can adversely affect quality of life, as it may produce significant morbidity. The American Association of Oral and Maxillofacial Surgeons (AAOMS) considers as vitally important that information on BRONJ be disseminated to other dental and medical specialties. The purpose of this work is to offer a perspective on how dentists should manage patients on BPs, to show the benefits of accurately diagnosing BRONJ, and to present diagnostic aids and treatments strategies for the condition.

[Bisphosphonates in adjuvant therapy of breast cancer]

For more than 10 years, based on the results with the bisphosphonate clodronic acid, it has been discussed, whether the occurrence of breast cancer metastases can be avoided or at least delayed by administration of bisphosphonates. The published results of recent studies applying, e.g., the bisphosphonates zoledronic and ibandronic acid, respectively, seem promising at first glance, especially, if the therapeutic acceptance of bisphosphonates in the indications osteoporosis and bone-related complications of malignancies, respectively, as well as their spectrum of side effects are taken into account and their putative mechanism of action is considered. There is a broad consensus that the existing data basis suffices to demonstrate importance of bisphosphonates in an adjuvant therapeutic setting of breast cancer. Significant relative risk reductions of, e.g., 36% in disease-free survival are very impressing and the corresponding absolute values of 3.2% are second-line communications. However, evaluation of all studies published so far according to the criteria of evidence-based medicine demonstrates many open questions and several methodical insufficiencies. Therefore, effectiveness and benefit of an adjuvant therapeutic application of bisphosphonates in breast cancer patients cannot be drawn out of evidence-based data. A recommendation of this therapy is given only by the German Working Pool of Gynecologic Oncology (AGO), but limited to study participation.

Zoledronic acid in the treatment of bone metastases by hepatocellular carcinoma: a case series

PURPOSE

The survival of patients with hepatocellular carcinoma (HCC) has improved with advancements in various diagnostic tools and treatment modalities. Consequently, bone metastases from HCC are diagnosed more frequently. The aims of the present study was to describe the clinical features and treatment of HCC patients presenting with bone metastases. In particular, we evaluated the role of zoledronic acid in these patients especially with regard to pain reduction, analgesic drug consumption and safety.

METHODS

Between December 2006 and July 2008, we recruited 17 (male:female, 12:5, median age, 68 years; age range, 62-85 years) consecutive patients. Spinal metastases were present in 11 patients (64.7%). Zoledronic acid was administered in all patients (total number of administrations, 107; mean number of administrations, 6.29).

RESULTS

A total of 15 patients received at least three administrations of zoledronic acid and reported clinical benefit with pain reduction and tapering of analgesic drugs. Before starting treatment, the mean VAS for patients who received at least three administrations (15/17 patients) of zoledronic acid was 7.1 (+/-0.24), and after 3 months 5.3 (+/-0.20). This improvement was independent of the sex, the extent of metastasis and the concomitant anticancer treatment. No significant side effects were registered in this series of patients. Median survival was 10 months (CI 6,353-13,647).

CONCLUSIONS

Zoledronic acid may be helpful in treating bone metastases in HCC patients. Patients regularly receiving zoledronic acid showed significant pain relief.