Bone turnover markers as predictive tools for skeletal complications in men with metastatic prostate cancer treated with zoledronic acid

Oncological validation of bone turnover markers c-terminal telopeptide of type I collagen (1CTP) and peptides n-terminal propeptide of type I procollagen (P1NP) in patients with prostate cancer and bone metastases

Background

Bone formation markers c-terminal telopeptide of type I collagen (1CTP) and peptides n-terminal propeptide of type I procollagen (P1NP) were reported to be increased in patients with prostate cancer (PC) and bone metastases. The objective of the presented study was to investigate the utility of serum 1CTP and P1NP values in the diagnosis of bone metastases and in predicting oncological outcome in patients with PC.

Methods

In total, serum samples of 186 patients were included retrospectively including 53 (28.50%) benign prostatic hyperplasia (BPH) patients and 133 (71.50%) PC-patients. The group of patients with PC consisted of 58 patients with non-metastatic PC (cM0) (43.61%) and 70 (52.63%) patients with bone metastases (cM1b). Serum 1CTP and P1NP were measured by radioimmunoassay (RIA). Results were compared to clinical variables including oncologic follow-up data by univariate and multivariate analyses.

Results

Median 1CTP concentrations were significantly higher in patients with PC compared to the BPH group [5.08 (range, 1.73–158.00) vs. 4.00 (range, 2.18–34.19) µg/L, P=0.019]. However, no significant difference of P1NP levels could be shown for these groups. With median values of 6.04 (1.73–158.00) and 3.91 µg/L (2.04–34.51) for 1CTP and 48.60 (9.12–1,074.37) and 33.90 (8.72–149.30) for P1NP both markers were altered in cM1b patients compared to cM0 patients (P=0.001 each). Furthermore, cancer-specific survival (CSS) and overall survival (OS) were significantly shorter in cM1b patients with higher 1CTP concentrations (P=0.037 and P=0.019, respectively), whereas no associations of P1NP and outcomes were observed.

Conclusions

The present study confirms that increased levels of 1CTP and P1NP concentrations are associated with presence of metastatic disease in the bone. Moreover, these markers are able to predict clinical course in PC patients with bone metastases. The potential use of these markers for treatment selection in advanced PC remains to be determined.

Prognostic value of alkaline phosphatase in hormone-sensitive prostate cancer: a systematic review and meta-analysis

Purpose

To assess the prognostic value of alkaline phosphatase in patients with hormone-sensitive prostate cancer.

Methods

A systematic review and meta-analysis was performed using the PUBMED, Web of Science, Cochrane Library, and Scopus in April 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. Studies were deemed eligible if they compared hormone-sensitive prostate cancer patients with high vs. low alkaline phosphatase to determine its predictive value for overall survival, cancer-specific survival, and progression-free survival. We performed a formal meta-analysis of these outcomes.

Results

42 articles with 7938 patients were included in the systematic review and 28 studies with 5849 patients for the qualitative assessment. High alkaline phosphatase was associated with worse overall survival (pooled HR 1.72; 95% CI 1.37−2.14) and progression-free survival (pooled HR 1.30; 95% CI 1.10−1.54). In subgroup analyses of patients with “high-volume” and “low-volume”, alkaline phosphatase was associated with the overall survival (pooled HR 1.41; 95% CI 1.21−1.64 and pooled HR 1.64; 95% CI, 1.06−2.52, respectively).

Conclusions

In this meta-analysis, elevated serum levels of alkaline phosphatase were associated with an increased risk of overall mortality and disease progression in patients with hormone-sensitive prostate cancer. In contrast, those were not associated with an increased risk of cancer-specific mortality. Alkaline phosphatase was independently associated with overall survival in both patients with “high-volume” and “low-volume” hormone-sensitive prostate cancer. Alkaline phosphatase may be useful for being integrated into prognostic tools that help guide treatment strategy, thereby facilitating the shared decision making process.

Elevated Serum Sialic Acid Levels Predict Prostate Cancer As Well As Bone Metastases

Objective: To evaluate the value of serum sialic acid (SA) in diagnosis of benign prostatic hyperplasia (BPH), prostate cancer (PCa), and bone metastases in PCa patients. Materials and Methods: Data from 540 patients who were newly diagnosed with PCa or BPH between November 2014 and March 2018 were retrospectively collected and analyzed. Pretreatment SA levels were compared across various groups, then, associations between SA levels and clinic parameters of patients were analyzed as well. Univariate and multivariate logistic regression analyses were further used to identify independent associations. Results: The mean SA levels in patients with PCa were significantly higher than with BPH (p = 0.013). Furthermore, PCa patients with bone metastases showed elevated SA levels compared with PCa without bone metastases (p < 0.001). A multivariate logistic regression model showed that: SA level > 52.35 mg/dL was identified to be independently associated with the diagnosis of PCa (HR = 1.645, p = 0.036), and SA level > 59 mg/dL was identified to be independent association with the presence of bone metastases in PCa patients (HR = 6.421, p = 0.012). Conclusions: Elevated SA level is an independent predictor of prostate cancer as well as its bone metastases. Therefore, SA level may be a promising diagnostic and prognostic biomarker for prostate cancer and bone metastases.

Severe Hypocalcemia and Hypomagnesemia with Denosumab in Advanced Chronic Kidney Disease: Case Report and Literature Review

Background

Denosumab has become the preferred agent over zolendronic acid to help prevent skeletal-related events in patients with metastatic bone disease and multiple myeloma because it is approved for use in those with kidney dysfunction. However, denosumab has been linked to cases of hypocalcemia, particularly in those with advanced kidney disease.

Case Presentation

We present the case of a patient with metastatic prostate cancer and chronic kidney disease due to obstructive nephropathy who developed severe hypocalcemia and hypomagnesemia after denosumab injection, which required intensive care unit admission, aggressive calcium supplementation, and hemodialysis assistance. We reviewed the evidence behind the safety profile of denosumab in chronic kidney disease, and we also looked at additional factors that may precipitate severe hypocalcemia with denosumab in advanced kidney disease.

Conclusion

We believe that denosumab should be avoided in advanced chronic kidney disease due to the potential life-threatening, severe hypocalcemia that has been observed.

Phase II study of radium-223 dichloride in Japanese patients with symptomatic castration-resistant prostate cancer

Background

Radium-223 dichloride (radium-223) is the first targeted alpha therapy approved for the treatment of castration-resistant prostate cancer (CRPC) with bone metastases. This study investigated the efficacy and safety of radium-223 in Japanese patients with symptomatic CRPC and bone metastases.

Methods

In this open-label, multicenter, phase II study, patients with progressive, symptomatic CRPC and bone metastases were treated with radium-223 (55 kBq/kg, intravenously) in a 4-week cycle for six cycles. The primary endpoint was the percent change in total alkaline phosphatase (ALP) from baseline at 12 weeks. Secondary endpoints included the percent ALP change from baseline to end of treatment (EOT), ALP response rates, percent change in prostate-specific antigen (PSA) from baseline to 12 weeks and EOT, PSA response rates, overall survival (OS), and time to symptomatic skeletal events (SSEs). Adverse events were monitored throughout the study period.

Results

Of the 49 Japanese patients (median age 74 years), 28 completed all infusions. Mean percent change in total ALP and PSA from baseline to 12 weeks was −19.3 and +97.4%, respectively. One-year OS and SSE-free rate at the end of active follow-up were 78 and 89%, respectively. The ALP response rate was 31%, while the PSA response rate was 6%. Grade 3/4 treatment-emergent adverse events observed in ≥10% of patients included decreased lymphocyte count (14%), anemia (14%), anorexia (10%), and bone pain (10%).

Conclusions

Radium-223 is effective and well tolerated in Japanese patients with CRPC and bone metastases. Results were comparable with the Alpharadin in Symptomatic Prostate Cancer Patients (ALSYMPCA) trial.

Clinical trial registration

ClinicalTrials.gov NCT01929655.

Electronic supplementary material

The online version of this article (doi:10.1007/s10147-017-1176-0) contains supplementary material, which is available to authorized users.

Safety and efficacy of radium-223 dichloride in Japanese patients with castration-resistant prostate cancer and bone metastases

Background

Radiation therapy with radium-223 dichloride improves overall survival, reduces symptomatic skeletal events in Caucasian patients with castration-resistant prostate cancer (CRPC) and bone metastases, and is well tolerated. We report here the results of the first efficacy and safety study of radium-223 dichloride in a Japanese population.

Methods

In this open-label, uncontrolled, non-randomized, phase I trial, radium-223 dichloride was given to Japanese patients with CRPC and ≥2 bone metastases in 4-week cycles. The patients were divided into three cohorts, with cohort 1 and the expansion cohort receiving injections of radium-223 dichloride [55 kBq/kg body weight (BW)] every 4 weeks (Q4W) for up to six injections, and cohort 2 receiving an initial single radium-223 dichloride injection of 110 kBq/kg BW followed by up to five injections of 55 kBq/kg BW Q4W. Safety was determined via adverse event (AE) reporting, and biochemical bone markers were assessed for treatment efficacy.

Results

In total 19 patients received at least one dose of radium-223 dichloride and 18 patients experienced at least one treatment-emergent AE (TEAE) of which the most common were anemia, thrombocytopenia, and lymphocytopenia. Serious AEs were reported in three patients but none were drug-related. In the patients of cohort 1 + expansion cohort (55 kBq/kg BW Q4W treatment; n = 16), prostate-specific antigen levels remained stable or slightly increased while the bone alkaline phosphatase (ALP) level significantly decreased. The response rates of bone ALP (≥30 and ≥50% reductions) were 81.8 and 36.4% at week 12, and 81.3 and 50.0% at the end of treatment.

Conclusions

Radium-223 dichloride was well tolerated in these Japanese patients and, at a dose of 55 kBq/kg BW, efficacy on biomarkers was as expected. The outcomes in Japanese patients were consistent with those reported in other non-Japanese populations.

Trial registration

ClinicalTrials.gov record NCT01565746.

Impressive response to denosumab in a patient with bone metastatic adenocarcinoma of the stomach after 2 years of zoledronic acid

Bone is a common site for tumor spread in patients with solid tumors. So far bisphosphonates have been the main pharmacological treatment option for patients with bone metastases. We present a case of bone metastatic gastric cancer treated with zoledronic acid at first and later with denosumab. After 1 year of denosumab treatment, the 18F-fluorodeoxyglucose (18F-FDG)-PET/computed tomography scan reassessment documented a metabolic complete response, even in the absence of specific antiblastic treatment. Whether denosumab can be used directly after pretreatment with bisphosphonates has yet to be addressed.

Prostate cancer and bone: the elective affinities

The onset of metastases dramatically changes the prognosis of prostate cancer patients, determining increased morbidity and a drastic fall in survival expectancy. Bone is a common site of metastases in few types of cancer, and it represents the most frequent metastatic site in prostate cancer. Of note, the prevalence of tumor relapse to the bone appears to be increasing over the years, likely due to a longer overall survival of prostate cancer patients. Bone tropism represents an intriguing challenge for researchers also because the preference of prostate cancer cells for the bone is the result of a sequential series of targetable molecular events. Many factors have been associated with the peculiar ability of prostate cancer cells to migrate in bone marrow and to determine mixed osteoblastic/osteolytic lesions. As anticipated by the success of current targeted therapy aimed to block bone resorption, a better understanding of molecular affinity between prostate cancer and bone microenvironment will permit us to cure bone metastasis and to improve prognosis of prostate cancer patients.

Procollagen assays in cancer

The synthesis rates of fibrillar collagens can be assessed in blood by measuring propeptides set free from corresponding procollagens before fiber formation. Type I collagen is the major component of the organic matrix of bone, but it is also found in other connective tissues. The serum concentration of the amino-terminal propeptide of type I procollagen, PINP, functions as a measure of type I collagen synthesis during normal bone turnover, but it is also released from bone metastases that involve an osteoblastic component. Type III collagen is a major constituent of soft tissues and the corresponding amino-terminal propeptide, PIIINP, reflects collagen synthesis. Circulating PIIINP tends to be affected by malignomas that grow in the peritoneal cavity or affect bone marrow. Many studies on procollagen markers in cancer have been cross-sectional or demonstrated treatment effects in patient groups. Markers that originate from bone turnover have wide reference intervals, but low biologic variability in individuals. Thus, they appear better suited for monitoring versus diagnostic purposes. There is still definite need for research on the use of procollagen markers in the followup of individual patients undergoing cancer treatment or being monitored after such treatment.

Bone markers for monitoring efficacy in patients with bone metastases receiving zoledronic acid: a review of published data

Bone metastases occur frequently in patients with advanced solid tumors and can create serious clinical problems that are commonly referred to as skeletal-related events. Although bisphosphonates, especially zoledronic acid, have emerged as an integral determinant of managing metastatic bone disease, their application remains a challenge because of the lack of standardized measures and their side effects. Since factors derived from bone metabolism are potentially useful to measure the efficacy of zoledronic acid, several clinical trials have investigated these bone markers with respect to their monitoring values. The results suggest that a greater decline in bone marker levels is associated with a more reduced incidence of skeletal-related events and a better improvement of symptoms. This review summarizes the available evidence on the clinical use of bone markers in monitoring zoledronic acid in various cancers with bone metastases including breast, prostate and lung cancer.

Usefulness of bone turnover markers as predictors of mortality risk, disease progression and skeletal-related events appearance in patients with prostate cancer with bone metastases following treatment with zoledronic acid: TUGAMO study

Background:

Owing to the limited validity of clinical data on the treatment of prostate cancer (PCa) and bone metastases, biochemical markers are a promising tool for predicting survival, disease progression and skeletal-related events (SREs) in these patients. The aim of this study was to evaluate the predictive capacity of biochemical markers of bone turnover for mortality risk, disease progression and SREs in patients with PCa and bone metastases undergoing treatment with zoledronic acid (ZA).

Methods:

This was an observational, prospective and multicenter study in which ninety-eight patients were included. Patients were treated with ZA (4 mg every 4 weeks for 18 months). Data were collected at baseline and 3, 6, 9, 12, 15 and 18 months after the beginning of treatment. Serum levels of bone alkaline phosphtase (BALP), aminoterminal propeptide of procollagen type I (P1NP) and beta-isomer of carboxiterminal telopeptide of collagen I (β-CTX) were analysed at all points in the study. Data on disease progression, SREs development and survival were recorded.

Results:

Cox regression models with clinical data and bone markers showed that the levels of the three markers studied were predictive of survival time, with β-CTX being especially powerful, in which a lack of normalisation in visit 1 (3 months after the beginning of treatment) showed a 6.3-times more risk for death than in normalised patients. Levels of these markers were also predictive for SREs, although in this case BALP and P1NP proved to be better predictors. We did not find any relationship between bone markers and disease progression.

Conclusion:

In patients with PCa and bone metastases treated with ZA, β-CTX and P1NP can be considered suitable predictors for mortality risk, while BALP and P1NP are appropriate for SREs. The levels of these biomarkers 3 months after the beginning of treatment are especially important.

Denosumab in patients with cancer and skeletal metastases: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review of the literature to determine the efficacy and safety of denosumab in reducing skeletal-related events (SRE) in patients with bone metastases.

METHODS

A literature search using MEDLINE, EMBASE, Web of Science and The Cochrane Collaboration Library identified relevant controlled clinical trials up-to-March 14, 2012. Two independent reviewers assessed studies for inclusion, according to predetermined criteria, and extracted relevant data. The primary outcomes of interest were SRE, time to first on-study SRE, and overall survival. Secondary outcomes included pain, quality of life, bone turnover markers (BTM), and adverse events.

RESULTS

Six controlled trials including 6142 patients were analyzed. Compared to zoledronic acid, denosumab had lower incidence of SRE with a risk ratio (RR) of 0.84 (95% confidence intervals (CI) 0.80-0.88), delayed the onset of first on-study SRE (RR 0.83; 95% CI 0.75-0.90) and time to worsening of pain (RR 0.84; 95% CI 0.77-0.91). No difference was observed in overall survival with pooled hazard ratio of 0.98 (95% CI 0.90-1.0). For total adverse events, denosumab was similar to zoledronic acid (RR 0.97; 95% CI 0.89-1.0). No significant differences were observed in the frequency of osteonecrosis of the jaw (RR 1.4; 95% CI 0.92-2.1). Patients on denosumab had a greater risk of developing hypocalcemia (RR 1.9; 95% CI 1.6-2.3).

CONCLUSIONS

Denosumab was more effective than zoledronic acid in reducing the incidence of SRE, and delayed the time to SRE. No differences were found between denosumab and zoledronic acid in reducing overall mortality, or in the frequency of overall adverse events.

Prognostic and predictive value of clinical and biochemical factors in breast cancer patients with bone metastases receiving "metronomic" zoledronic acid

Background

To assess prognostic and predictive effects of clinical and biochemical factors in our published randomized study of a weekly low dose (metronomic arm) versus a conventional dosage of zoledronic acid (conventional arm) in breast cancer patients with bone metastases.

Methods

Treatment outcome of 60 patients with bone metastases were used to assess impacts of following potential prognostic factors, estrogen receptor status, lymph node status, 2 year-disease free interval (DFI), numbers of chemotherapy regimens administered, interventions, and serum levels of VEGF, N-telopeptide of type I collagen (NTx), CEA, and CA 15-3.

Results

In univariate analyses, patients pretreated with 2 or fewer chemotherapy regimens, ER-positive tumors, 3 or fewer lymph nodes, DFI of more than 2 years, serum VEGF of less than 500 pg/mL after 3 months of intervention, serum CEA and CA 15-3 of less than ULN, and baseline serum NTx of less than 18 nM BCE had significantly longer progression free survival (PFS). The multivariate analysis showed that ER positivity (hazard ratio [HR], 0.295; 95% confidence interval [CI], 0.141-0.618; P = 0.001), serum VEGF of less than 500 pg/mL after 3 months of intervention (HR, 2.220; 95% CI, 1.136-4.338; P = 0.020), baseline serum NTx of less than 18 nM BCE (HR, 2.842; 95% CI, 1.458-5.539; P = 0.001), and 2 or fewer chemotherapy regimens received (HR, 7.803; 95% CI, 2.884-21.112; P = 0.000) were associated with a better PFS. When evaluating the predictive effect of the biochemical factors, an interaction between NTx and zoledronic acid intervention was shown (P = 0.005). The HR of weekly low dose versus a conventional dosage of zoledronic acid was estimated to be 2.309 (99% CI, 1.067-5.012) in patients with baseline serum NTx of more than 18 nM BCE, indicating a superiority of weekly low dose of zoledronic acid.

Conclusions

ER, serum VEGF level after intervention, and numbers of chemotherapy regimens administered are prognostic but not predictive factors in breast cancer patients with bone metastases. Patients with baseline serum NTx of more than 18 nM BCE might benefit more from weekly low-dose of zoledronic acid.

Trial registration

ClinicalTrials.gov unique identifier: ClinicalTrials.gov: NCT00524849

Bone-marker levels in patients with prostate cancer: potential correlations with outcomes

PURPOSE OF REVIEW

The skeleton is typically the first site of metastasis in patients with prostate cancer, and bone metastases can result in severe bone pain and potentially debilitating fractures. Although bone scans are a reliable means of assessing osteoblastic lesions, tools for monitoring early changes in bone health are lacking. Biochemical markers of bone turnover might fulfill this unmet need.

RECENT FINDINGS

Correlative studies have suggested that bone-marker levels may have utility in assessing disease progression and response to bone-directed therapy. Elevated levels of the markers, N-telopeptide of type I collagen and bone-specific alkaline phosphatase, are associated with higher rates of death and skeletal-related events in the bone metastasis setting. Marker levels also correlate with response to zoledronic acid treatment, and similar data with the investigational agent, denosumab, are emerging.

SUMMARY

Changes in bone-marker levels reflect alterations in skeletal homeostasis and can provide important insights into bone disease progression and response to bone-directed therapy in patients with prostate cancer. More mature data from currently ongoing clinical trials will provide further insight on the utility of marker assessments as an adjunct to established monitoring methods in prostate cancer.

Increases in bone turnover marker levels at an early phase after starting zoledronic acid predicts skeletal-related events in patients with prostate cancer with bone metastasis

OBJECTIVE

To examine whether bone turnover markers could be predictive markers of the probability of newly arising skeletal-related events (SRE) after the start of zoledronic acid treatment in patients with prostate cancer with bone metastasis.

PATIENTS AND METHODS

In all, 30 patients with prostate cancer with bone metastasis were treated with zoledronic acid infusion every 4 weeks. Serum C-terminal crosslinking telopeptide of type 1 collagen (1CTP), bone alkaline phosphatase (BAP), and prostate-specific antigen (PSA) levels were measured at the start of zoledronic acid treatment to establish baseline values, and every 4 weeks thereafter. To judge in the early phase whether zoledronic acid is effective in these patients, we retrospectively compared 1CTP, BAP, and PSA levels at 1, 3, and 6 months after starting zoledronic acid treatment with those at baseline.

RESULTS

SRE-free survival of patients with increases of 1CTP levels at 1 and 3 months and BAP levels at 3 months were significantly poorer than those of patients with decreases in 1CTP or BAP levels (P = 0.001, P = 0.042, and P = 0.004, respectively). Overall survival of patients with increases of 1CTP levels at 1 and 3 months and of BAP levels at 6 months were significantly poorer than those of patients with decreases of 1CTP or BAP levels (P = 0.013, P = 0.027, and P = 0.035, respectively).

CONCLUSION

The measurement of 1CTP and BAP levels at an early phase after starting zoledronic acid treatment may be useful for physicians to inform patients of their prognosis and to determine the subsequent treatment plan.

Serum N-Terminal Propeptide of Collagen Type I is Associated with the Number of Bone Metastases in Breast and Prostate Cancer and Correlates to Other Bone Related Markers

Background

A number of biomarkers have been proven potentially useful for their ability to indicate bone metastases (BM) in cancer patients. The aim of this study was to investigate the relative utility of a newly developed N-terminal propeptide of collagen type I (PINP) human serum assay for the detection of BM in cancer patients. This assay has a corresponding rat PINP assay which in the future might help in translational science between rodent and human trials.

Methods

Participants were 161 prostate, lung and breast cancer patients stratified by number of BM (Soloway score). PINP was assessed and correlated to number of BM. Additionally, the PINP marker was correlated to bone resorption of young (ALPHA CTX-I)- and aged bone (BETA CTX-I); number of osteoclasts (Tartrate-resistant acid phosphatase 5b, TRACP5B) and osteoclast activity (CTX-I/ TRACP5B).

Results

PINP was significantly elevated in breast- and prostate cancer patients +BM, compared to −BM (P < 0.001), however not in lung cancer patients. A strong linear association was seen between PINP and the number of BMs. Significant elevation of PINP was observed at Soloway scores 1–4 (<0 BM) compared with score 0 (0 BM) (P < 0.001). The correlation between bone resorption of young bone or aged bone and bone formation was highly significant in patients +BM and −BM (P < 0.0001).

Conclusions

Data suggest that the present PINP potentially could determine skeletal involvement in patients with breast or prostate cancer. Correlations suggested that coupling between bone resorption and bone formation was maintained in breast- and prostate cancer patients.

Recent advances in the use of serological bone formation markers to monitor callus development and fracture healing

The failure of an osseous fracture to heal, or the development of a nonunion, is common; however, current diagnostic measures lack the capability of early and reliable detection of such events. Analyses of radiographic imaging and clinical examination, in combination, remain the gold standard for diagnosis; however, these methods are not reliable for early detection. Delayed diagnosis of a nonunion is costly from both the patient and treatment standpoints. In response, repeated efforts have been made to identify bone metabolic markers as diagnostic or prognostic tools for monitoring bone healing. Thus far, the evidence regarding a correlation between the kinetics of most bone metabolic markers and nonunion is very limited. With the aim of classifying the role of biological pathways of bone metabolism and of understanding bone conditions in the development of osteoporosis, advances have been made in our knowledge of the molecular basis of bone remodeling, fracture healing, and its failure. Procollagen type I amino-terminal propeptide has been shown to be a reliable bone formation marker in osteoporosis therapy and its kinetics during fracture healing has been recently described. In this article, we suggest that procollagen type I amino-terminal propeptide presents a good opportunity for early detection of nonunion. We also review the role and potential of serum PINP, as well as other markers, as indications of fracture healing.

Evolving role of bone biomarkers in castration-resistant prostate cancer

The preferential metastasis of prostate cancer cells to bone disrupts the process of bone remodeling and results in lesions that cause significant pain and patient morbidity. Although prostate-specific antigen (PSA) is an established biomarker in prostate cancer, it provides only limited information relating to bone metastases and the treatment of metastatic bone disease with bisphosphonates or novel noncytotoxic targeted or biological agents that may provide clinical benefits without affecting PSA levels. As bone metastases develop, factors derived from bone metabolism are released into blood and urine, including N- and C-terminal peptide fragments of type 1 collagen and bone-specific alkaline phosphatase, which represent potentially useful biomarkers for monitoring metastatic bone disease. A number of clinical trials have investigated these bone biomarkers with respect to their diagnostic, prognostic, and predictive values. Results suggest that higher levels of bone biomarkers are associated with an increased risk of skeletal-related events and/or death. As a result of these findings, bone biomarkers are now being increasingly used as study end points, particularly in studies investigating novel agents with putative bone effects. Data from prospective clinical trials are needed to validate the use of bone biomarkers and to confirm that marker levels provide additional information beyond traditional methods of response evaluation for patients with metastatic prostate cancer.

Bone turnover markers as predictors of mortality risk in prostate cancer patients with bone metastases following treatment with zoledronic acid

BACKGROUND

Clinical data have limited validity for predicting the survival of prostate cancer (PCa) patients with bone metastases. There is a need to improve the predictive evidence both for clinicians and patients.

OBJECTIVE

To evaluate the predictive ability of serum bone markers for mortality risk in PCa patients with bone metastases.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a survival analysis in relation to bone markers in a subgroup of 52 patients treated with zoledronic acid (4 mg every 4 wk for 15 mo) in a prospective, multicentre trial during 2002-2005, about 4 yr after the end of the trial.

MEASUREMENTS

Serum levels of total and bone-specific alkaline phosphatase, amino-terminal procollagen propeptides of type I collagen (PINP), cross-linked N-terminal (NTx) and cross-linked C-terminal telopeptides of type I collagen (ICTP), C-terminal telopeptides of type I collagen, prostate-specific antigen from the last visit of the treatment study, and clinical data were related to the overall survival (OS) status of patients in the follow-up. Univariate and multivariate Cox regression analyses with internal bootstrapping validation and concordance index calculations were performed.

RESULTS AND LIMITATIONS

Out of the 52 patients followed, 34 died within a median follow-up of 13.8 mo, and 18 patients were alive at a median follow-up of 43.8 mo. The patients who died within the follow-up period had significantly higher concentrations of ICTP, NTx, and PINP than the surviving patients. Cox regression models with clinical data and bone markers showed that ICTP and PINP were most predictive for mortality risk in addition to the occurrence of skeletal-related complications and the continuation of treatment with zoledronic acid. Internal validation confirmed the reliability of the results, although the sample size was small.

CONCLUSIONS

PINP and ICTP can be considered suitable predictors for the OS of PCa patients with bone metastases.

Pathologic fracture and metastatic spinal cord compression in patients with prostate cancer and bone metastases

Background

The purpose of this study was to determine the risk factors for and incidence as well as prognostic impact of pathologic fracture (PF) and metastatic spinal cord compression (MSCC) in patients with bone metastases (BM) from prostate cancer.

Methods

Retrospective cohort study including 61 consecutive patients seen at Nordland hospital's department of oncology between 2007 and 2009. The initial diagnosis of BM might have been made earlier. Twenty-nine patients (48%) received taxotere and 72% zoledronic acid after diagnosis of BM.

Results

Median actuarial survival after diagnosis of BM was 23 months. Six patients (10%) were alive at 5 years. Bone pain at baseline was present in 49% of patients. Eighty-nine percent required external beam radiotherapy and/or radioisotopes after diagnosis of BM. Seventeen patients (28%) developed at least one major skeletal complication, i.e. MSCC or PF (4 of them developed more than one). The actuarial risk was 44% at 4 and 5 years. Most events developed before treatment with zoledronic acid and/or taxotere. Median survival from diagnosis of either MSCC or PF was 11 months (5 months from MSCC). We did not identify statistically significant risk factors for development of major skeletal complications. Serum alkaline phosphatase above median value and age less than or equal to 70 years were the only risk factors approaching significance.

Conclusions

We found high rates of major skeletal complications in this unselected contemporary group of patients. Identification of risk factors might guide the development of early interventions aiming at prevention of MSCC and PF.

Biochemical markers of bone turnover and clinical outcomes in men with prostate cancer

OBJECTIVES

Disrupted skeletal homeostasis is common in patients with prostate cancer. Low bone density is common at diagnosis, and fracture risk is further elevated by the effects of androgen-deprivation therapy. Later in the disease course, bone metastases can result in skeletal morbidity. Although prostate-specific antigen (PSA) levels can provide important insights into overall disease progression, convenient, noninvasive tools for monitoring skeletal health are lacking. Biochemical markers released into serum and urine as a result of bone turnover might fulfill this unmet need. The objectives of this article are to assess current evidence examining the potential utility of bone turnover markers for monitoring skeletal health, bone disease progression, and response to antiresorptive therapies in the prostate cancer setting.

METHODS

Published articles and abstracts from major oncology or urology congresses pertaining to the use of bone turnover markers to monitor skeletal health and disease progression were identified and assessed for relevance and methodologic stringency.

RESULTS

Several randomized trials and correlative studies support the utility of bone marker level changes to assess disease progression in the metastatic setting, bone health during hormonal therapy, and response to bisphosphonate therapy. The available data support potential associations between levels of the collagen type I telopeptides (NTX and CTX) and the severity of metastatic bone disease as well as outcomes during antiresorptive therapy. Evidence linking bone marker level changes with early diagnosis of skeletal metastases is emerging. Although several markers have shown promising results in correlative studies, results from ongoing prospective trials are needed to establish the role of bone markers in this setting.

CONCLUSIONS

Bone marker levels reflect ongoing skeletal metabolism and can provide important insights into bone health and response to bisphosphonate therapy in patients with prostate cancer. The data supporting a role for bone markers to monitor skeletal disease progression and response to zoledronic acid therapy are especially strong. Bone marker assessments may complement established diagnostic and monitoring paradigms in prostate cancer.

ABT-888 confers broad in vivo activity in combination with temozolomide in diverse tumors

PURPOSE

ABT-888, currently in phase 2 trials, is a potent oral poly(ADP-ribose) polymerase inhibitor that enhances the activity of multiple DNA-damaging agents, including temozolomide (TMZ). We investigated ABT-888+TMZ combination therapy in multiple xenograft models representing various human tumors having different responses to TMZ.

EXPERIMENTAL DESIGN

ABT-888+TMZ efficacy in xenograft tumors implanted in subcutaneous, orthotopic, and metastatic sites was assessed by tumor burden, expression of poly(ADP-ribose) polymer, and O(6)-methylguanine methyltransferase (MGMT).

RESULTS

Varying levels of ABT-888+TMZ sensitivity were evident across a broad histologic spectrum of models (55-100% tumor growth inhibition) in B-cell lymphoma, small cell lung carcinoma, non-small cell lung carcinoma, pancreatic, ovarian, breast, and prostate xenografts, including numerous regressions. Combination efficacy in otherwise TMZ nonresponsive tumors suggests that TMZ resistance may be overcome by poly(ADP-ribose) polymerase inhibition. Profound ABT-888+TMZ efficacy was seen in experimental metastases models that acquired resistance to TMZ. Moreover, TMZ resistance was overcome in crossover treatments, indicating that combination therapy may overcome acquired TMZ resistance. Neither tumor MGMT, mismatch repair, nor poly(ADP-ribose) polymer correlated with the degree of sensitivity to ABT-888+TMZ.

CONCLUSIONS

Robust ABT-888+TMZ efficacy is observed across a spectrum of tumor types, including orthotopic and metastatic implantation. As many TMZ nonresponsive tumors proved sensitive to ABT-888+TMZ, this novel combination may broaden the clinical use of TMZ beyond melanoma and glioma. Although TMZ resistance may be influenced by MGMT, neither MGMT nor other mechanisms of TMZ resistance (mismatch repair) precluded sensitivity to ABT-888+TMZ. Underlying mechanisms of TMZ resistance in these models are not completely understood but likely involve mechanisms independent of MGMT.