Effects of single-agent bortezomib as post-transplant consolidation therapy on multiple myeloma-related bone disease: a randomized phase II study

Full or intensity-reduced high-dose melphalan and single or double autologous stem cell transplant with or without bortezomib consolidation in patients with newly diagnosed multiple myeloma

OBJECTIVE

A post hoc subgroup analysis of two phase III trials (NCT00416273, NCT00416208) was carried out to investigate the influence of 100/140 and 200 mg/m² melphalan as well as single/double autologous stem cell transplantation (ASCT) on progression-free survival (PFS). Additionally, the effect of bortezomib consolidation on PFS was analyzed.

METHODS

Following induction therapy and high-dose melphalan with subsequent ASCT, patients with newly diagnosed multiple myeloma (NDMM) were randomized 1:1 to either four 35-day cycles of bortezomib consolidation (1.6 mg/m² IV on days 1, 8, 15, 22) or observation.

RESULTS

Of the 340 patients included in this analysis, 13.5% received 1 × MEL100/140, 22.9% 2 × MEL100/140, 31.2% 1 × MEL200, and 32.4% 2 × MEL200. With higher cumulative melphalan dose, PFS improved (P = .0085). PFS curves of patients treated with 2 × MEL100/140 and 1 × MEL200 were very similar. The superior dose effect of MEL200 over MEL100/140 was non-existent in the bortezomib consolidation arm but pronounced in the observation arm (P = .0015). Similarly, double ASCT was only beneficial in patients without bortezomib consolidation (P = .0569).

CONCLUSIONS

Full dose melphalan and double transplantation seem advantageous only as long as patients are not receiving bortezomib consolidation afterwards.

The role of novel agents for consolidation after autologous transplantation in newly diagnosed multiple myeloma: a systematic review

Despite the increasing inclusion of novel agents within the multiple myeloma (MM) treatment sequence, their role for posttransplant consolidation therapy remains unclear. We systematically reviewed studies evaluating the efficacy of novel agent consolidation. We identified 11 citations on 12 prospective comparative studies, and 5 citations were single-arm or comparative studies with preliminary results. Nine different regimens were evaluated in 5905 patients. Risk assessment yielded serious risk of bias and heterogeneity across study designs was high. Irrespective of the regimen, deepened responses after consolidation were seen and improvements were more pronounced with multi-agent consolidation. Bortezomib, thalidomide, and dexamethasone improved long-term survival versus duplet consolidation, including in patients with high-risk cytogenetics. The addition of daratumumab to triplet regimens yielded modestly improved responses with significantly increased rates of minimal residual disease negativity but survival results were limited by short follow-up. In high-risk MM, responses were not different, whereas progression-free survival appeared to be improved with consolidation therapy, challenging the association of response and overall outcome in this subgroup. Our findings highlight the necessity of longer follow-up and consistent reporting to ensure comparability of studies to enable better evidence assessment and to identify patients benefitting from consolidation therapy.

Bortezomib-based consolidation or maintenance therapy for multiple myeloma: a meta-analysis

Bortezomib-based regimens are widely used as induction therapy for multiple myeloma (MM). Unlike lenalidomide, the role of bortezomib in consolidation and maintenance therapy for MM is less clear. We performed a meta-analysis to evaluate the impact of bortezomib-based consolidation and maintenance therapy on survival outcomes and adverse events. PubMed, Web of Science, Embase databases, and major conference proceedings were searched for randomized controlled trials (RCTs) of bortezomib-based regimens as consolidation or maintenance therapy for MM. Ten RCTs enrolling 3147 patients were included in the meta-analysis. Bortezomib-based regimens were compared with regimens without bortezomib or observation. The meta-analysis suggested that bortezomib-based maintenance therapy improved progression-free survival (PFS; hazard ratio [HR] = 0.72, 95% CI 0.55-0.95, P = 0.02) and overall survival (OS; HR = 0.71, 95% CI 0.58-0.87, P = 0.001). Bortezomib-based consolidation therapy improved PFS (HR = 0.77, 95% CI 0.68-0.88, P < 0.001) but not OS (HR = 0.98, 95% CI 0.78-1.24, P = 0.87). Bortezomib-based consolidation/maintenance therapy led to a trend toward increased risk of grade ≥ 3 neurologic symptoms, gastrointestinal symptoms, and fatigue. More research is warranted to further assess the role of bortezomib-based consolidation and maintenance therapy for multiple myeloma.

Preventing and Repairing Myeloma Bone Disease by Combining Conventional Antiresorptive Treatment With a Bone Anabolic Agent in Murine Models

Multiple myeloma is a plasma cell malignancy, which develops in the bone marrow and frequently leads to severe bone destruction. Current antiresorptive therapies to treat the bone disease do little to repair damaged bone; therefore, new treatment strategies incorporating bone anabolic therapies are urgently required. We hypothesized that combination therapy using the standard of care antiresorptive zoledronic acid (Zol) with a bone anabolic (anti-TGFβ/1D11) would be more effective at treating myeloma-induced bone disease than Zol therapy alone. JJN3 myeloma-bearing mice (n = 8/group) treated with combined Zol and 1D11 resulted in a 48% increase (p ≤ 0.001) in trabecular bone volume (BV/TV) compared with Zol alone and a 65% increase (p ≤ 0.0001) compared with 1D11 alone. Our most significant finding was the substantial repair of U266-induced osteolytic bone lesions with combination therapy (n = 8/group), which resulted in a significant reduction in lesion area compared with vehicle (p ≤ 0.01) or Zol alone (p ≤ 0.01). These results demonstrate that combined antiresorptive and bone anabolic therapy is significantly more effective at preventing myeloma-induced bone disease than Zol alone. Furthermore, we demonstrate that combined therapy is able to repair established myelomatous bone lesions. This is a highly translational strategy that could significantly improve bone outcomes and quality of life for patients with myeloma. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Consolidation therapy with the combination of bortezomib and lenalidomide (VR) without dexamethasone in multiple myeloma patients after transplant: Effects on survival and bone outcomes in the absence of bisphosphonates

Optimizing consolidation treatment in transplant-eligible newly diagnosed multiple myeloma patients in order to improve efficacy and bone-related outcomes is intriguing. We conducted an open-label, prospective study evaluating the efficacy and safety of bortezomib and lenalidomide (VR) consolidation after ASCT, in the absence of dexamethasone and bisphosphonates. Fifty-nine patients, who received bortezomib-based induction, were given 4 cycles of VR starting on day 100 post-ASCT. After ASCT, 58% of patients improved their response status, while following VR consolidation 39% further deepened their response; stringent complete response rates increased to 51% after VR from 24% post-ASCT. VR consolidation resulted in a significant reduction of soluble receptor activator of nuclear factor-κB ligand/osteoprotegerin ratio and sclerostin circulating levels, which was more pronounced among patients achieving very good partial response or better. After a median follow-up of 62 months, no skeletal-related events (SREs) were observed, despite the lack of bisphosphonates administration. The median TTP after ASCT was 37 months, while median overall survival (OS) has not been reached yet; the probability of 4- and 5-year OS was 81% and 64%, respectively. In conclusion, VR consolidation is an effective, dexamethasone- and bisphosphonate-free approach, which offers long OS with improvements on bone metabolism and no SREs.

Metastatic bone disease: Pathogenesis and therapeutic options: Up-date on bone metastasis management

Bone metastases (BM) are a common complication of cancer, whose management often requires a multidisciplinary approach. Despite the recent therapeutic advances, patients with BM may still experience skeletal-related events and symptomatic skeletal events, with detrimental impact on quality of life and survival. A deeper knowledge of the mechanisms underlying the onset of lytic and sclerotic BM has been acquired in the last decades, leading to the development of bone-targeting agents (BTA), mainly represented by anti-resorptive drugs and bone-seeking radiopharmaceuticals. Recent pre-clinical and clinical studies have showed promising effects of novel agents, whose safety and efficacy need to be confirmed by prospective clinical trials. Among BTA, adjuvant bisphosphonates have also been shown to reduce the risk of BM in selected breast cancer patients, but failed to reduce the incidence of BM from lung and prostate cancer. Moreover, adjuvant denosumab did not improve BM free survival in patients with breast cancer, suggesting the need for further investigation to clarify BTA role in early-stage malignancies. The aim of this review is to describe BM pathogenesis and current treatment options in different clinical settings, as well as to explore the mechanism of action of novel potential therapeutic agents for which further investigation is needed.

Insights on Multiple Myeloma Treatment Strategies

The introduction of new agents and management strategies over the past decade has resulted in a major step change in treatment outcomes with deepening responses and increased survival for patients with multiple myeloma. In daily clinical practice, healthcare professionals are now faced with challenges including, optimal treatment sequencing and changing treatment goals. In light of this, a group of experts met to discuss diagnostic and treatment guidelines, examine current clinical practice, and consider how new clinical trial data may be integrated into the management of multiple myeloma in the future.

New agents in the Treatment of Myeloma Bone Disease

Patients with multiple myeloma develop a devastating bone disease driven by the uncoupling of bone remodelling, excess osteoclastic bone resorption and diminished osteoblastic bone formation. The bone phenotype is typified by focal osteolytic lesions leading to pathological fractures, hypercalcaemia and other catastrophic bone events such as spinal cord compression. This causes bone pain, impaired functional status, decreased quality of life and increased mortality. Early in the disease, malignant plasma cells occupy a niche environment that encompasses their interaction with other key cellular components of the bone marrow microenvironment. Through these interactions, osteoclast-activating factors and osteoblast inhibitory factors are produced, which together uncouple the dynamic process of bone remodelling, leading to net bone loss and focal osteolytic lesions. Current management includes antiresorptive therapies, i.e. bisphosphonates, palliative support and orthopaedic interventions. Bisphosphonates are the mainstay of treatment for myeloma bone disease (MBD), but are only partially effective and do have some significant disadvantages; for example, they do not lead to the repair of existing bone destruction. Thus, newer agents to prevent bone destruction and also promote bone formation and repair existing lesions are warranted. This review summarises novel ways that MBD is being therapeutically targeted.

Fixed duration vs continuous therapy in multiple myeloma

The introduction of new drugs with less severe toxicity profiles than those of conventional antimyeloma agents allowed the evaluation of continuous therapy compared with fixed duration therapy. In transplant-eligible patients, consolidation therapy with bortezomib or bortezomib-based regimens showed significant progression-free survival (PFS) benefit in cytogenetic standard-risk patients and to a lesser extent, high-risk patients. Continuous therapy with lenalidomide maintenance treatment after autologous stem cell transplantation resulted in a significant survival gain. In transplant noneligible patients, continuous lenalidomide-dexamethasone therapy improved survival over fixed duration melphalan-prednisone-thalidomide. The concept of prolonged treatment in elderly patients is supported by some other studies, but most of them revealed a gain in PFS only. Young patients with unfavorable prognosis show a greater willingness to accept long-term treatment, whereas the readiness to undergo such treatments and the benefits therefrom decline with increasing age and decreasing fitness, rendering fixed duration therapy a suitable option in elderly frail patients.

Myeloma and Bone Disease

PURPOSE OF REVIEW

Bone disease is a defining characteristic of multiple myeloma (MM) and the major cause of morbidity. It manifests as lytic lesions or osteopenia and is often associated with severe pain, pathological fracture, spinal cord compression, vertebral collapse, and hypercalcemia. Here, we have reviewed recent data on understanding its biology and treatment.

RECENT FINDINGS

The imbalance between bone regeneration and bone resorption underlies the pathogenesis of osteolytic bone disease. Increased osteoclast proliferation and activity accompanied by inhibition of bone-forming osteoblasts leads to progressive bone loss and lytic lesions. Although tremendous progress has been made, MM remains an incurable disease. Novel agents targeting bone disease are under investigation with the goal of not only preventing bone loss and improving bone quality but also harnessing MM tumor growth. Current data illustrate that the interactions between MM cells and the tumor-bone microenvironment contribute to the bone disease and continued MM progression. A better understanding of this microenvironment is critical for novel therapeutic treatments of both MM and associated bone disease.