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Background: Multiple myeloma is characterised by monoclonal paraprotein production and osteolytic lesions, commonly leading to skeletal-related events (spinal cord compression, pathological fracture, or surgery or radiotherapy to affected bone). Denosumab, a monoclonal antibody targeting RANKL, reduces skeletal-related events associated with bone lesions or metastases in patients with advanced solid tumours. This study aimed to assess the efficacy and safety of denosumab compared with zoledronic acid for the prevention of skeletal-related events in patients with newly diagnosed multiple myeloma.Methods: In this international, double-blind, double-dummy, randomised, active-controlled, phase 3 study, patients in 259 centres and 29 countries aged 18 years or older with symptomatic newly diagnosed multiple myeloma who had at least one documented lytic bone lesion were randomly assigned (1:1; centrally, by interactive voice response system using a fixed stratified permuted block randomisation list with a block size of four) to subcutaneous denosumab 120 mg plus intravenous placebo every 4 weeks or intravenous zoledronic acid 4 mg plus subcutaneous placebo every 4 weeks (both groups also received investigators' choice of first-line antimyeloma therapy). Stratification was by intent to undergo autologous transplantation, antimyeloma therapy, International Staging System stage, previous skeletal-related events, and region. The clinical study team and patients were masked to treatment assignments. The primary endpoint was non-inferiority of denosumab to zoledronic acid with respect to time to first skeletal-related event in the full analysis set (all randomly assigned patients). All safety endpoints were analysed in the safety analysis set, which includes all randomly assigned patients who received at least one dose of active study drug. This study is registered with ClinicalTrials.gov, number NCT01345019.Findings: From May 17, 2012, to March 29, 2016, we enrolled 1718 patients and randomly assigned 859 to each treatment group. The study met the primary endpoint; denosumab was non-inferior to zoledronic acid for time to first skeletal-related event (hazard ratio 0·98, 95% CI 0·85-1·14; pnon-inferiority=0·010). 1702 patients received at least one dose of the investigational drug and were included in the safety analysis (850 patients receiving denosumab and 852 receiving zoledronic acid). The most common grade 3 or worse treatment-emergent adverse events for denosumab and zoledronic acid were neutropenia (126 [15%] vs 125 [15%]), thrombocytopenia (120 [14%] vs 103 [12%]), anaemia (100 [12%] vs 85 [10%]), febrile neutropenia (96 [11%] vs 87 [10%]), and pneumonia (65 [8%] vs 70 [8%]). Renal toxicity was reported in 85 (10%) patients in the denosumab group versus 146 (17%) in the zoledronic acid group; hypocalcaemia adverse events were reported in 144 (17%) versus 106 (12%). Incidence of osteonecrosis of the jaw was not significantly different between the denosumab and zoledronic acid groups (35 [4%] vs 24 [3%]; p=0·147). The most common serious adverse event for both treatment groups was pneumonia (71 [8%] vs 69 [8%]). One patient in the zoledronic acid group died of cardiac arrest that was deemed treatment-related.Interpretation: In patients with newly diagnosed multiple myeloma, denosumab was non-inferior to zoledronic acid for time to skeletal-related events. The results from this study suggest denosumab could be an additional option for the standard of care for patients with multiple myeloma with bone disease.Funding: Amgen. [ABSTRACT FROM AUTHOR]

Background: Histone deacetylase (HDAC) inhibitors are an important new class of therapeutics for treating multiple myeloma. Ricolinostat (ACY-1215) is the first oral selective HDAC6 inhibitor with reduced class I HDAC activity to be studied clinically. Motivated by findings from preclinical studies showing potent synergistic activity with ricolinostat and lenalidomide, our goal was to assess the safety and preliminary activity of the combination of ricolinostat with lenalidomide and dexamethasone in relapsed or refractory multiple myeloma.Methods: In this multicentre phase 1b trial, we recruited patients aged 18 years or older with previously treated relapsed or refractory multiple myeloma from five cancer centres in the USA. Inclusion criteria included a Karnofsky Performance Status score of at least 70, measureable disease, adequate bone marrow reserve, adequate hepatic function, and a creatinine clearance of at least 50 mL per min. Exclusion criteria included previous exposure to HDAC inhibitors; previous allogeneic stem-cell transplantation; previous autologous stem-cell transplantation within 12 weeks of baseline; active systemic infection; malignancy within the last 5 years; known or suspected HIV, hepatitis B, or hepatitis C infection; a QTc Fridericia of more than 480 ms; and substantial cardiovascular, gastrointestinal, psychiatric, or other medical disorders. We gave escalating doses (from 40-240 mg once daily to 160 mg twice daily) of oral ricolinostat according to a standard 3 + 3 design according to three different regimens on days 1-21 with a conventional 28 day schedule of oral lenalidomide (from 15 mg [in one cohort] to 25 mg [in all other cohorts] once daily) and oral dexamethasone (40 mg weekly). Primary outcomes were dose-limiting toxicities, the maximum tolerated dose of ricolinostat in this combination, and the dose and schedule of ricolinostat recommended for further phase 2 investigation. Secondary outcomes were the pharmacokinetics and pharmacodynamics of ricolinostat in this combination and the preliminary anti-tumour activity of this treatment. The trial is closed to accrual and is registered at ClinicalTrials.gov, number NCT01583283.Findings: Between July 12, 2012, and Aug 20, 2015, we enrolled 38 patients. We observed two dose-limiting toxicities with ricolinostat 160 mg twice daily: one (2%) grade 3 syncope and one (2%) grade 3 myalgia event in different cohorts. A maximum tolerated dose was not reached. We chose ricolinostat 160 mg once daily on days 1-21 of a 28 day cycle as the recommended dose for future phase 2 studies in combination with lenalidomide 25 mg and dexamethasone 40 mg. The most common adverse events were fatigue (grade 1-2 in 14 [37%] patients; grade 3 in seven [18%]) and diarrhoea (grade 1-2 in 15 [39%] patients; grade 3 in two [5%]). Our pharmacodynamic studies showed that at clinically relevant doses, ricolinostat selectively inhibits HDAC6 while retaining a low and tolerable level of class I HDAC inhibition. The pharmacokinetics of ricolinostat and lenalidomide were not affected by co-administration. In a preliminary assessment of antitumour activity, 21 (55% [95% CI 38-71]) of 38 patients had an overall response.Interpretation: The findings from this study provide preliminary evidence that ricolinostat is a safe and well tolerated selective HDAC6 inhibitor, which might partner well with lenalidomide and dexamethasone to enhance their efficacy in relapsed or refractory multiple myeloma.Funding: Acetylon Pharmaceuticals. [ABSTRACT FROM AUTHOR]