Expert opinion 2011 on the use of new anti-resorptive agents in the prevention of skeletal-related events in metastatic bone disease

Evidence on the analgesic role of bisphosphonates and denosumab in the treatment of pain due to bone metastases: A systematic review within the European Association for Palliative Care guidelines project

BACKGROUND

Bisphosphonates and denosumab are well-established therapies to reduce the frequency and severity of skeletal-related events in patients with bone metastasis. However, the analgesic effect of these medications on bone pain is uncertain.

AIM

To identify, critically appraise and synthesize existing evidence to answer the following questions: 'In adult patients with metastatic bone pain, what is the evidence that bisphosphonates and denosumab are effective and safe in controlling pain?' and 'What is the most appropriate schedule of bisphosphonate/denosumab administration to control bone pain?'. This review also updates the 2002 Cochrane review 'Bisphosphonates for the relief of pain secondary to bone metastases'.

DESIGN

Standard systematic review and narrative synthesis.

DATA SOURCES

MEDLINE, EMBASE and Cochrane CENTRAL databases were searched for relevant articles published through 31 January 2014. A manual search was also performed. Study inclusion criteria were: a) conducted in adult patients; b) randomized controlled trial or meta-analisys; c) reported efficacy of bisphosphonates or denosumab on pain and/or decribed side effects versus placebo or other bisphosphonate; and d) English language.

RESULTS

The database search yielded 1585 studies, of which 43 (enrolling 8595 and 7590 patients, respectively, in bisphosphonate and denosumab trials) met the inclusion criteria. Twenty-two (79%) of the 28 placebo-controlled trials found no analgesic benefit for bisphosphonates. None of the denosumab studies assessed direct pain relief.

CONCLUSION

Evidence to support an analgesic role for bisphosphonates and denosumab is weak. Bisphosphonates and denosumab appear to be beneficial in preventing pain by delaying the onset of bone pain rather than by producing an analgesic effect per se.

New anti-resorptives and antibody mediated anti-resorptive therapy

The ageing population and an increase in both the incidence and prevalence of cancer pose a healthcare challenge, some of which is borne by the orthopaedic community in the form of osteoporotic fractures and metastatic bone disease. In recent years there has been an increasing understanding of the pathways involved in bone metabolism relevant to osteoporosis and metastases in bone. Newer therapies may aid the management of these problems. One group of drugs, the antibody mediated anti-resorptive therapies (AMARTs) use antibodies to block bone resorption pathways. This review seeks to present a synopsis of the guidelines, pharmacology and potential pathophysiology of AMARTs and other new anti-resorptive drugs. We evaluate the literature relating to AMARTs and new anti-resorptives with special attention on those approved for use in clinical practice. Denosumab, a monoclonal antibody against Receptor Activator for Nuclear Factor Kappa-B Ligand. It is the first AMART approved by the National Institute for Health and Clinical Excellence and the US Food and Drug Administration. Other novel anti-resorptives awaiting approval for clinical use include Odanacatib. Denosumab is indicated for the treatment of osteoporosis and prevention of the complications of bone metastases. Recent evidence suggests, however, that denosumab may have an adverse event profile similar to bisphosphonates, including atypical femoral fractures. It is, therefore, essential that orthopaedic surgeons are conversant with these medications and their safe usage.

TAKE HOME MESSAGE

Denosumab has important orthopaedic indications and has been shown to significantly reduce patient morbidity in osteoporosis and metastatic bone disease.

Side effects of bone-targeted therapies in advanced breast cancer

In up to 75% of cases, advanced breast cancer patients eventually develop bone metastases with often debilitating skeletal-related events (SREs). Osteoclast inhibitors are commonly used as therapeutic mainstay with clinical studies showing superiority of denosumab over bisphosphonates (e.g., zoledronate) for the prevention of SREs. The present review discusses the adverse event profile of these agents, and addresses the prevention and management of untoward side effects. Adverse events associated with osteoclast inhibitors comprise osteonecrosis of the jaw and hypocalcemia. Hypocalcemia is more common with denosumab, particularly in severe renal dysfunction. During therapy, the appropriate prevention of these adverse events includes close attention to dental health, avoidance of invasive dental procedures, supplementation with calcium and vitamin D unless patients are hypercalcemic, and regular monitoring of relevant serum values. Relating to the risk of nephrotoxicity, bisphosphonates but not denosumab have been incriminated. Therefore, serum creatinine levels should be checked prior to each dose of zoledronate, and in severe renal dysfunction (creatinine clearance < 30 ml/min) zoledronate is contraindicated anyway. Acute-phase reactions are particularly linked to bisphosphonates. Consequently, if these adverse events predominate, switching to denosumab is recommended.