Rethinking end-points for bone-targeted therapy in advanced cancer

Circulating Osteocalcin-Positive Cells as a Novel Diagnostic Biomarker for Bone Metastasis in Breast Cancer Patients

Current diagnosis of bone metastasis (BM) in breast cancer relies on structural changes of bone that occur only in the advanced stage. A sensitive biomarker for detecting early progression of bone metastasis is urgently required. We performed clinical and preclinical studies to investigate diagnostic value of circulating osteocalcin-positive cells (cOC) in breast cancer bone metastasis. Metastatic breast cancer patients (n = 92) with or without bone metastasis (ie, BM⁺ or BM^- ) were enrolled, and cOC were measured at enrollment. Patients were followed up for bone metastasis progression for 18 months. BM⁺ patients (n = 59) were divided into progressive (PD) or stable disease (SD) groups, based on imaging studies at the end of the 18-month study. The PD group had higher baseline cOC compared with the SD group. Furthermore, higher cOC resulted in reduced BM progression-free survival. Three patients in the BM^- group (n = 33) developed new BM during the 18-month study, and these patients had a higher level of baseline cOC compared with the remaining BM^- patients. In murine preclinical studies, cOC increased at early time points when micro-metastases were evident only by histology but undetectable by bioluminescence imaging. Also, cOC levels predicted the progression of BM and correlated significantly with BM tumor burden. cOC increased in the early phase of breast cancer BM and can predict BM progression, supporting cOC as a potential novel biomarker. © 2020 American Society for Bone and Mineral Research.

Efficacy and safety of de-escalation bone- modifying agents for cancer patients with bone metastases: a systematic review and meta-analysis

Background

Compared with application of bone-modifying agents (BMAs) every 4 weeks, it is unclear whether 12-weekly de-escalated therapy can be used as a substitute strategy.

Methods

A systematic search of PubMed, EMBASE, and the Cochrane Register of Controlled Trials until November 22, 2017, was performed. Randomized controlled trials (RCTs) were included to assess skeletal-related event (SRE) rates, adverse events, and bone turnover biomarkers, comparing 12-weekly de-escalated treatments with standard 4-weekly dosage regimens. Risk ratios (RRs) with 95% CIs were pooled in fixed-effect meta-analyses.

Results

A total of eight citations were eligible comprising 2,878 patients: zoledronate (three studies, 2,650 patients), pamidronate (two studies, 68 patients), and denosumab (three studies, 160 patients). Summary RR (0.98; 95% CI 0.87–1.12; P=0.82) for SRE rates between de-escalated and standard arms was produced when seven low risk of bias trials (695 patients) were pooled, and results without statistical significance also appeared in the analysis of adverse events and bone turnover biomarkers. Due to the limited sample size and methodological differences, the data for skeletal morbidity rates (SMRs), time to first SRE, serum C-telopeptide (sCTx) levels, and hypocalcemia were not combined, but systematic review still obtained similar indistinguishableness.

Conclusion

In this meta-analysis of randomized clinical trials, the results “appeared” to show non-inferiority of the 12-weekly treatment. Due to the difference in available data, the results for bisphosphonates are more solid than for the receptor activator of nuclear factor-κB ligand (RANKL) antibodies.

Relevance of randomised controlled trials in oncology

Well-designed randomised controlled trials (RCTs) can prevent bias in the comparison of treatments and provide a sound basis for changes in clinical practice. However, the design and reporting of many RCTs can render their results of little relevance to clinical practice. In this Personal View, we discuss the limitations of RCT data and suggest some ways to improve the clinical relevance of RCTs in the everyday management of patients with cancer. RCTs should ask questions of clinical rather than commercial interest, avoid non-validated surrogate endpoints in registration trials, and have entry criteria that allow inclusion of all patients who are fit to receive treatment. Furthermore, RCTs should be reported with complete accounting of frequency and management of toxicities, and with strict guidelines to ensure freedom from bias. Premature reporting of results should be avoided. The bar for clinical benefit should be raised for drug registration, which should require publication and review of mature data from RCTs, post-marketing health outcome studies, and value-based pricing.

Novel Methodology for Comparing Standard-of-Care Interventions in Patients With Cancer

Purpose:

The current clinical trials development and conduct process is cumbersome and expensive, with the majority of studies focusing on either the development of new agents or new indications for established agents. Unfortunately, research comparing standard-of-care interventions is rarely performed, leaving many important and practical patient-centered questions unanswered. Novel clinical trial methodologies and approaches are needed.

Methods:

We have identified simple key components that, when combined, enhance the ability to both perform and increase accrual for studies that compare standard-of-care interventions. These include selection of clinically relevant and practical questions, demonstration of clinical equipoise through surveys of knowledge users and completion of systematic reviews, appropriate study design and simply defined study end points, use of an integrated consent model incorporating oral consent, efficient research ethics board approval, Web-based randomization in the clinic, real-time electronic data capture and management, and regular formal team feedback.

Results:

We have demonstrated the feasibility of this model in a pragmatic trial comparing two standard-of-care interventions (growth factor support or ciprofloxacin) for the primary prophylaxis of febrile neutropenia in patients with breast cancer receiving adjuvant docetaxel with cyclophosphamide chemotherapy. Research ethics board approval took 3 months, and 110 (72%) of 153 potentially eligible patients have agreed to participate in the study. When surveyed, 81 (85%) of 95 patients were completely satisfied with the integrated consent model process.

Conclusion:

Our proposed model contains elements that, when used alone or in combination, may allow efficient and cost-effective comparison of standard-of-care interventions.