Do You Want to Stay Single? Considerations on Single-Arm Trials in Drug Development and the Postregulatory Space.

Single-arm trials (SATs), while not preferred, remain in use throughout the drug development cycle. They may be accepted by regulators in particular contexts (e.g., in oncology or rare diseases) when the potential effects of new treatments are very large and placebo treatment is unethical. However, in the postregulatory space, SATs are common, and perhaps even more poorly suited to address the questions of interest. In this manuscript, we review regulatory and HTA positions on SATs; challenges posed by SATs to address research questions beyond regulators, evolving statistical methods to provide context for SATs, case studies where SATs could and could not address questions of interest, and communication strategies to influence decision making and optimize study design to address evidence needs.

Durability of symptomatic responses obtained with adjunctive vagus nerve stimulation in treatment-resistant depression.

OBJECTIVE: To compare the durations of response achieved with adjunctive vagus nerve stimulation (VNS + TAU) vs treatment as usual (TAU) alone in treatment-resistant depression (TRD) over a 5-year period in the TRD registry. MATERIALS AND METHODS: Data from 271 participants on TAU and 328 participants on VNS + TAU were analyzed. Response was defined as ≥50% decrease in baseline Montgomery-Åsberg Depression Rating Scale (MADRS) score at postbaseline visit and was considered retained until the decrease was <40%. MADRS was obtained quarterly in year 1 and biannually thereafter. Time-to-events were estimated using Kaplan-Meier method and compared using log-rank test. HR was estimated using Cox proportion hazard model. RESULTS: In the VNS + TAU arm, 62.5% (205/328) of participants had a first response over 5 years compared with 39.9% (108/271) in TAU. The time to first response was significantly shorter for VNS + TAU than for TAU (P<0.01). For responders in the first year, median time to relapse from first response was 10.1 months (Q1=4.2, Q3=31.5) for VNS + TAU vs 7.3 months (Q1=3.1, Q3=17.6) for TAU (P<0.01). HR=0.6 (95% CI: 0.4, 0.9) revealed a significantly lower chance for relapse in VNS + TAU. Probability of retaining first response for a year was 0.39 (0.27, 0.51) for TAU and 0.47 (0.38, 0.56) for VNS + TAU. Timing of the onset of the response did not impact the durability of the response. CONCLUSION: VNS therapy added to TAU in severe TRD leads to rapid onset and higher likelihood of response, and a greater durability of the response as compared to TAU alone.

Improving Probabilities of Correct Interim Decision in Population Enrichment Designs.

Choice of target population is an essential part at the design stage of clinical trials. Data from earlier clinical development might suggest that the treatment is more effective in a subpopulation, but there might not be enough evidence to restrict the target population upfront. Adaptive designs allow modification of the target population based on interim data. Decision for modification should be based on objective decision rules. The presented decision rules maximize the weighted probability of correct interim decisions based on prior assumptions. Evaluation of decision rules in the planning phase can improve probabilities of correct interim decision and power.

A multicenter phase 1 study of EMD 525797 (DI17E6), a novel humanized monoclonal antibody targeting αv integrins, in progressive castration-resistant prostate cancer with bone metastases after chemotherapy.

BACKGROUND: EMD 525797 (DI17E6) is a deimmunized, humanized monoclonal immunoglobulin G2 antibody against the αv subunit of human integrins. Blocking αv integrins may be an effective strategy for inhibiting prostate cancer (PCa) metastasis. OBJECTIVE: Evaluate EMD 525797 safety/tolerability and pharmacokinetics (PK) in castration-resistant PCa patients. Secondary objectives included antitumor activity assessments. DESIGN, SETTING, AND PARTICIPANTS: A phase 1 open-label study in 26 patients (four European centers). Eligible patients (≥ 18 yr) had histologically proven PCa with bone metastases after prior chemotherapy and evidence of progressive disease (PD) based on prostate-specific antigen (PSA) values. INTERVENTION: Patients received three intravenous EMD 525797 infusions (250, 500, 1000, or 1500 mg every 2 wk). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Treatment-emergent adverse events (TEAEs) and dose-limiting toxicities (DLTs) were assessed. PK parameters were calculated according to noncompartmental standard methods. Antitumor activity measures were response after 6 wk, changes in PSA levels, and pain interference total score. Descriptive statistics were used. RESULTS AND LIMITATIONS: Patients were treated for a mean of 16.8 ± 16.7 wk. No DLTs were reported in any of the cohorts. All patients experienced TEAEs, which were considered drug-related in 11 patients. Four deaths occurred during the trial and were considered not related to EMD 525797. EMD 525797 showed dose-dependent, nonlinear PK. Eighteen of 26 patients did not show PD for ≥ 18 wk. Two patients (500-mg cohort), treated for 42.4 and 76.3 wk, had clinically significant PSA reductions and pain relief, including one patient with confirmed partial response. This trial was not specifically designed to assess clinical activity, and further investigations are needed in randomized controlled trials. CONCLUSIONS: No DLTs were reported in any of the evaluated cohorts. There was evidence of clinical activity. For the currently ongoing phase 2 trial, EMD 525797 doses of 750 and 1500 mg every 3 wk were chosen. TRIAL REGISTRATION: NCT00958477 (EMR 62242-002).

Tolerability and dose-related effects of nebivolol in elderly patients with heart failure: data from the Study of the Effects of Nebivolol Intervention on Outcomes and Rehospitalisation in Seniors with Heart Failure (SENIORS) trial.

BACKGROUND: The SENIORS trial showed that nebivolol reduced the risk of death or cardiovascular (CV) hospitalization in elderly patients with heart failure (HF). We aimed to assess tolerability and dose-related effects of the beta-blocker nebivolol in elderly patients from the SENIORS trial. METHODS: Patients assigned to nebivolol (n = 1031) were classified into 4 groups, according to the dose achieved at the end of titration phase (maintenance dose): 0 mg (n = 74), low dose (1.25 or 2.5 mg, n = 142), medium dose (5 mg, n = 127), and target dose (10 mg, n = 688) and compared with those allocated to placebo (n = 1030). Age, sex and ejection fraction were similar between the groups, but prior myocardial infarction, coronary revascularization, and serum creatinine levels were lower in patients who achieved higher maintenance doses of nebivolol. RESULTS: After adjustment, all-cause mortality or CV hospitalization was significantly reduced in the 10 mg dose group compared with placebo (hazard ratio [HR] 0.75, 95% CI 0.63-0.90) which was similar to the medium dose group (HR 0.73, 95% CI 0.52-1.02). The low dose group had an apparently lower benefit (HR 0.88, 95% CI 0.64-1.20), whereas patients unable to tolerate any dose of nebivolol had an increased risk of death or CV hospitalization (HR 1.95, 95% CI 1.38-2.75). CONCLUSIONS: The benefits of nebivolol in elderly patients with HF appear to be related to the maintenance dose achieved. Patients unable to tolerate any dose have the worst prognosis.

Effects of nebivolol in elderly heart failure patients with or without systolic left ventricular dysfunction: results of the SENIORS echocardiographic substudy.

AIMS: The SENIORS trial recently demonstrated that nebivolol reduces the composite risk of all-cause mortality and cardiovascular hospital admission in elderly patients with chronic heart failure and, importantly, that ejection fraction does not influence the clinical effects of nebivolol. An echocardiographic substudy was designed to evaluate the effects of nebivolol on systolic and diastolic left ventricular (LV) function in patients stratified according to the presence or absence of systolic LV dysfunction. METHODS AND RESULTS: The substudy randomized 112 patients in 29 European centres, of whom 104 were evaluable for the study; 43 had an ejection fraction (EF) 35%. LV end-systolic volume (ESV), EF, mitral valve E/A ratio, and E-wave deceleration time were assessed at baseline and after 12 months. Echocardiograms were submitted to a core laboratory to perform quantitative analysis in blinded condition. In the group with EF35% group, no significant changes in either systolic or diastolic parameters were observed. CONCLUSION: In patients with heart failure and advanced systolic LV dysfunction, nebivolol reduces ventricular size and improves EF. The absence of detectable changes with standard echocardiography in patients with predominant diastolic heart failure questions the mechanism of benefit on morbidity/mortality in such patients.