Sequence- and concentration-dependent effects of acute and long-term exposure to the bisphosphonate ibandronate in combination with single and multiple fractions of ionising radiation doses in human breast cancer cell lines

Evaluation of the clinical benefit of long-term (beyond 2 years) treatment of skeletal-related events in advanced cancers with zoledronic acid

BACKGROUND

Skeletal complications of malignant bone disease are common among patients with both solid tumors and multiple myeloma (MM). Zoledronic acid (ZOL; Zometa*) is an intravenous bisphosphonate with proven efficacy in reducing the incidence of skeletal complications and delaying the time to a first skeletal complication. This study was designed to assess the continued benefit of ZOL treatment over a prolonged period.

METHODS

This was a retrospective claims analysis study using information gathered from two national US managed-care plan databases. Patients ≥18 years of age with a single type of solid tumor or MM who were diagnosed with bone lesions and experienced at least one skeletal complication (before or after receiving ZOL) were included.

RESULTS

Of the 28,385 patients, those with lung and breast cancer composed the largest group. Greater percentages of MM and breast cancer patients were treated with ZOL. On average, those with renal cell carcinoma and lung cancer had a longer time between bone metastasis diagnosis and start of therapy with ZOL. Compared with an untreated cohort, patients treated with ZOL had a 24% reduction in incidence of fracture, a 45% reduction in incidence of spinal cord compression, and a 56% reduction in risk of mortality. Patients with persistence with ZOL over 180 days had a reduced incidence of fracture before controlling for other factors.

CONCLUSIONS

Patients treated with ZOL had reduced risks of fracture, spinal cord compression, and mortality compared with patients in the no-treatment cohort. Longer persistence with ZOL was associated with better outcomes. Greatest benefits were observed for patients treated on a regular basis with ZOL for a period beyond 18 months.

Is there a role for ibandronate in the treatment of prostate cancer patients with bony metastases?

PURPOSE

Zoledronic acid is widely accepted as the treatment of choice for a number of cancers which metastasise to bone and is the only bisphosphonate licensed for the treatment of prostate cancer. However, drug related nephrotoxicity, although rare, does pose a significant complication when using zoledronic acid. Prostate cancer patients are generally older than 65 years of age and already exhibit some form of impaired renal function. Thus, for prostate cancer patients who are unable to tolerate zoledronic acid there is a need for an alternative bisphosphonate. One possibility could be ibandronate which is also a potent third generation, nitrogen-containing bisphosphonate and is an attractive choice for some patients due to the fact it is available in both intravenous and oral preparations.

METHODS

This article reviews the current published literature regarding the use of ibandronate in the treatment of metastatic prostate cancer.

RESULTS

Preliminary data emerging from small Phase II studies suggests ibandronate may provide a therapeutic alternative for the treatment of metastatic prostate cancer when zoledronic acid is deemed unsuitable.

CONCLUSION

Further in vivo research with ibandronate in prostate cancer is urgently needed in order to elucidate whether this bisphosphonate may play a role in the treatment and palliative management of metastatic prostate cancer.

Guidance on the use of bisphosphonates in solid tumours: recommendations of an international expert panel

Bisphosphonates (BP) prevent, reduce, and delay cancer-related skeletal complications in patients, and have substantially decreased the prevalence of such events since their introduction. Today, a broad range of BP with differences in potency, efficacy, dosing, and administration as well as approved indications is available. In addition, results of clinical trials investigating the efficacy of BP in cancer treatment-induced bone loss (CTIBL) have been recently published. The purpose of this paper is to review the current evidence on the use of BP in solid tumours and provide clinical recommendations. An interdisciplinary expert panel of clinical oncologists and of specialists in metabolic bone diseases assessed the widespread evidence and information on the efficacy of BP in the metastatic and nonmetastatic setting, as well as ongoing research on the adjuvant use of BP. Based on available evidence, the panel recommends amino-bisphosphonates for patients with metastatic bone disease from breast cancer and zoledronic acid for patients with other solid tumours as primary disease. Dosing of BP should follow approved indications with adjustments if necessary. While i.v. administration is most often preferable, oral administration (clodronate, IBA) may be considered for breast cancer patients who cannot or do not need to attend regular hospital care. Early-stage cancer patients at risk of developing CTIBL should be considered for preventative BP treatment. The strongest evidence in this setting is now available for ZOL. Overall, BP are well-tolerated, and most common adverse events are influenza-like syndrome, arthralgia, and when used orally, gastrointestinal symptoms. The dose of BP may need to be adapted to renal function and initial creatinine clearance calculation is mandatory according to the panel for use of any BP. Subsequent monitoring is recommended for ZOL and PAM, as described by the regulatory authority guidelines. Patients scheduled to receive BP (mainly every 3-4 weeks i.v.) should have a dental examination and be advised on appropriate measures for reducing the risk of jaw osteonecrosis. BP are well established as supportive therapy to reduce the frequency and severity of skeletal complications in patients with bone metastases from different cancers.

Bisphosphonate treatment and radiotherapy in metastatic breast cancer

Patients with advanced breast cancer frequently develop metastasis to bone. Bone metastasis results in intractable pain and high risk of pathologic fractures due to osteolysis. The treatment of breast cancer patients with bone metastases requires a multidisciplinary approach. Radiotherapy is an established treatment for metastatic bone pain. It may be delivered either as a localized low dose treatment for localized bone pain or systemically for more widespread symptoms. Bisphosphonates have been shown to reduce morbidity and bone pain from bone metastases when given to patients with metastatic bone disease. In vivo studies indicate that early bisphosphonates administration in combination with radiotherapy improves remineralization and restabilization of osteolytic bone metastases in animal tumor models. This review focused on a brief discussion about biology of bone metastases, the effects of radiotherapy and bisphosphonate therapy, and possible mechanisms of combination therapy in metastatic breast cancer patients.