Clodronate and other bisphosphonates as supportive therapy in osteolysis due to malignancy

Apoptotic pathways of macrophages within osteolytic interface membrane in periprosthestic osteolysis after total hip replacement

Macrophage apoptosis in interface membrane, which occurs through either death receptor, mitochondrion, or endoplasmic reticulum (ER) stress pathways, has been suggested to play an important role in promoting osteolysis. However, how and why macrophage apoptosis originates and the correlation among these apoptotic pathways is not yet clear. The objective of this study was to identify the apoptotic mechanism of macrophages, and to explore the relationship between the apoptotic pathways and progression of osteolysis. Transmission electron microscopy (TEM) was utilized to analyze the tissue ultrastructure of wear particles, and in situ apoptotic macrophage identification was performed by TUNEL staining. We analyzed the expression of the key biomarkers of apoptotic pathways via immunohistochemistry and Western blotting. Our results demonstrated that the majority of wear particles within osteolytic interface membrane was in the 30-60 nm range, and that macrophage apoptotic ratio increased along with osteolysis progression. Normal hip dysplasia and mechanical loosening of tissues showed low expression levels of biomarkers for ER stress (Ca²⁺ , JNK, cleaved Caspase-4, IRE1-α, Grp78/Bip, and CHOP), mitochondrion (Bcl-2, Bax, and Cytochrome c), and death receptor (Fas and cleaved Caspase-8) pathways, while osteolytic interface membrane tissues expressed high levels of these biomarkers. In addition, we found that the ER stress intensity was in complete conformity with mitochondrial dysfunction and was consistent with the results of death receptor activation. Thus, our findings suggested that wear particles generated at implant interface can accelerate macrophage apoptosis through changes in apoptotic pathways and ultimately aggravate the symptom of osteolysis. These data represent a preferential apoptotic signaling pathway of macrophages as specific target points for the prevention and therapeutic modulation of periprosthetic osteolysis.

Proven efficacy of zoledronic acid in the treatment of bone metastases in patients with breast cancer and other malignancies

Many advanced cancers, particularly breast cancer and prostate cancer, metastasize to the bone, resulting in painful lesions and skeletal complications. Intravenous bisphosphonate therapy is an important component of palliative care for patients with bone metastases, and pamidronate has been the standard of care for patients with breast cancer and multiple myeloma since 1996. However, zoledronic acid is the first bisphosphonate shown to significantly reduce skeletal morbidity in patients with a wide range of primary tumor types. Zoledronic acid has demonstrated efficacy in the management of hypercalcemia and metastatic bone disease. In phase III studies involving more than 3000 patients with multiple myeloma, breast cancer, prostate cancer, lung cancer, and other cancers, 4 mg zoledronic acid demonstrated consistent efficacy across a range of clinical end-points, and was safe and well tolerated when infused over 15 min. Based on these studies, zoledronic acid appears to be active in patients with bone metastases irrespective of tumor type, and should be considered as the standard of care for the treatment of bone metastases.

Use of bisphosphonates in skeletal metastasis

At present, there is sufficient evidence to propose practice guidelines that would include the use of bisphosphonates in the management of hypercalcemia, in breast cancer with bone metastases and multiple myeloma. Future research should concentrate on investigating the adjuvant use of bisphosphonates in breast cancer, particularly in order to find out the adequate target groups. Phase III studies comparing the old and new generation bisphosphonates are important as well as trials comparing the other palliative regimens with bisphosphonates. A widespread use of bisphosphonates would have a major impact on drug budgets. Does the cost of achieved palliation represent the optimal use of resources when compared with other possible options for palliation? This issue has not become easier with the emerging new expensive regimens in oncology. An economical analysis, ideally in the setting of randomized trials, is needed.

The effect of two different doses of oral clodronate on pain in patients with bone metastases

The aim of this study was to evaluate the efficacy of low dose oral clodronate in palliation of pain arising from bone metastases (BM) and to determine the optimal oral clodronate dose which inhibits osteolysis caused by tumor. Fifty patients with bone pain caused by BM were included in this study. All were receiving antitumor chemotherapy or hormonal therapy. The patients were randomized into three groups according to the dose of clodronate. Groups A and B were given 800 mg/d and 1600 mg/d of oral clodronate respectively for 3 months. Group C was the control group. The effect of clodronate in pain palliation was evaluated with pain score, performance status, and changes in analgesic use. The effect on osteolysis was examined with urinary calcium, hydroxyproline (OHP) and serum cross-linked carboxyterminal telopeptide region of type I collagen (ICTP) levels. Group A contained 16 patients, and groups B and C contained 17 patients each. After 3 months use of oral clodronate, significant decrease in the pain score of groups A and B was noted when compared to group C (P = 0.024 and P = 0.007, respectively). The analgesic use of 11 patients in group A (69%) and 8 patients in group B (47%) was decreased, but only the decrease in group A was statistically significant (P = 0.038). Pain score increased in 5 patients in group C (29%), and 3 patients in groups A (19%) and B (18%) each. Urinary calcium, OHP and serum ICTP levels increased in group C and decreased in groups A and B, but only the decrease of urinary calcium levels of group B was significant (P = 0.003). In conclusion, low dose (800 mg/d) oral clodronate seems to be as effective as standard dose (1600 mg/d) in palliation of bone pain secondary to BM.

Time-dependent changes of serum carboxy-terminal peptide of type I procollagen and carboxy-terminal telopeptide of type I collagen concentrations in patients with acute myocardial infarction after successful reperfusion: correlation with left ventricular volume indices

To test the hypothesis that in patients with acute myocardial infarction (AMI), changes in the concentrations of the serum carboxy-terminal peptide of type I procollagen (PICP) and the carboxy-terminal telopeptide of type I collagen (ICTP) reflect extracellular matrix reformation and degradation, respectively, in the infarct healing processes, we measured these serum concentrations by RIA and compared their values with left ventricular (LV) indices obtained by left ventriculography. We studied 13 consecutive patients with their first AMI who underwent successful reperfusion. Blood samples were taken the day of admission and on days 2, 3, 4, 5, 7, and 14. LV volume indices were determined at 1 month after AMI, when LV remodeling was almost completed. The serum concentrations of both PICP and ICTP changed in a time-dependent manner. The average serum PICP concentration was lower than 1 SD below the mean control values on days 2 and 3 and increased thereafter, returning to the lower end of the control range at day 14. The area under the curve (AUC) for PICP was significantly correlated with the LV end systolic (ES) and end diastolic (ED) volume indices and LV ejection fraction for the first 14 days after AMI. The serum PICP on days 5–14 was inversely correlated or tended to be correlated with the LVES and LVED volume indices. The average serum ICTP concentrations on admission were within the control range, began to increase on day 2, and reached maximal concentrations on day 5, remaining at a plateau concentration until day 14. Although the AUC of ICTP for 14 days, the ICTP concentrations on days 1 and 14, and the minimal and maximal concentrations were significantly correlated with creatine kinase (CK) release and the period from AMI onset to the peak CK time, the concentrations were not significantly correlated with any LV indices except for the concentration on day 4, which was weakly correlated with the LVES volume index. The serum concentrations of PICP showed a significant time-dependent change that correlated with LV indices, indicating that PICP may provide additional information for evaluating the healing process because it affects LV remodeling after AMI. Although the serum concentration of ICTP changed in association with CK release, the ICTP concentration was found to be a poor indicator for LV indices.

Palliative treatment of bone metastases

Bone metastases are frequently one of the first signs of disseminated disease in cancer patients and are especially seen in patients with breast, prostate and lung cancer. The prognosis of these patients is generally poor and the treatment is primarily palliative: the intention is to relieve pain, prevent fractures, maintain activity and, if possible, to prolong survival. Besides analgesics the therapeutic options include local treatment with radiotherapy and/or surgery, and systemic treatment using chemotherapy, endocrine therapy, radioisotopes as well as bisphosphonates. Social and psychological supportive care is also very important. Radiotherapy plays an important role, but the other modalities such as bisphosphonates may also offer the same level of palliation, but their definite role has not been as clearly defined. There have been few randomized trials comparing the therapeutic options, and the criteria for assessing response to therapy have, in general, been poorly defined. There is a need for rigorous clinical investigations which assess the efficacy of the various therapeutic possibilities by using well-defined and validated response criteria such as pain and quality of life.

Bisphosphonate therapy in metastatic breast cancer

Five long-term controlled studies on the effect of supportive bisphosphonate treatment in metastatic breast cancer with bone metastases have been published. In two of the studies pamidronate was used and in three clodronate. According to these trials supportive bisphosphonate treatment in metastatic breast cancer diminishes the risk of malignant, pathological fractures and bone pain. In several of these trials a retarding effect on the progression of previous and new bone metastases could also be documented. One further large trial, hitherto published only in abstract form, indicates that the development of bone invasion can also be retarded by bisphosphonate treatment in patients with metastatic breast cancer without bone metastases.