Transplantation of discarded livers following viability testing with normothermic machine perfusion

There is a limited access to liver transplantation, however, many organs are discarded based on subjective assessment only. Here we report the VITTAL clinical trial (ClinicalTrials.gov number NCT02740608) outcomes, using normothermic machine perfusion (NMP) to objectively assess livers discarded by all UK centres meeting specific high-risk criteria. Thirty-one livers were enroled and assessed by viability criteria based on the lactate clearance to levels ≤2.5 mmol/L within 4 h. The viability was achieved by 22 (71%) organs, that were transplanted after a median preservation time of 18 h, with 100% 90-day survival. During the median follow up of 542 days, 4 (18%) patients developed biliary strictures requiring re-transplantation. This trial demonstrates that viability testing with NMP is feasible and in this study enabled successful transplantation of 71% of discarded livers, with 100% 90-day patient and graft survival; it does not seem to prevent non-anastomotic biliary strictures in livers donated after circulatory death with prolonged warm ischaemia.

The shortage of viable donated livers limits patient access to liver transplantation. Here the authors report the use of normothermic machine perfusion to help identify viable organs from livers discarded based on current clinical criteria, which are then transplanted to recipients in a single-arm clinical trial.

Immune activation in first-in-human anti-macrophage antibody (anti-Clever-1 mAb; FP-1305) phase I/II MATINS trial: Part I dose-escalation, safety, and efficacy results

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Background: The scavenger receptor CLEVER-1 mediates the clearance of “unwanted” self-components and is highly expressed on tumor associated macrophages (TAMs). CLEVER-1 expression is associated with immunotherapy resistance and poor survival in several cancers. Pre-clinical studies demonstrate that CLEVER-1 inhibition increases TAM pro-inflammatory cytokine secretion and antigen presentation reactivating CD8 T cell responses with robust anti-tumor activity. Targeting CLEVER-1 could therefore overcome the immunosuppressive tumor microenvironment and has led to the development of FP-1305, a humanized anti-CLEVER-1 IgG4-antibody. Methods: The MATINS (Macrophage Antibody To INhibit immune Suppression) trial is a multicenter first-in-human phase I/II study (NCT03733990) to assess the tolerability, safety and preliminary efficacy of FP-1305 in patients (pts) with advanced cancers including immunotherapy-refractory melanoma, cholangiocarcinoma, hepatocellular carcinoma, ovarian cancer, colorectal (CRC), and pancreatic ductal adenocarcinoma. Part 1 consisted of a dose escalation phase; 30 pts (median age 65, range 30-81) were enrolled to examine 5 dose levels (0.1, 0.3, 1.0, 3.0, 10 mg/kg), to determine the optimal dose of FP-1305 for Parts 2 and 3. Two-stage time-to-event continual reassessment method (TITE-CRM) was utilized for the dose escalation in Part 1. Pts received 1-8 cycles (median 3) of FP-1305 Q3w. FP-1305 was well tolerated without dose-limiting toxicities. A consistent increase in blood NK cells, CD8/CD4 T cell ratio, B cells and a decrease in regulatory T cells was demonstrated. FP-1305 dosing led to the activation (CD25+) and Th1 skewing (CXCR3+) of T cell populations including increase in effector CD8 T-cells with downregulation of several inhibitory immune checkpoint molecules (PD-1, PD-L1, CTLA-4, and LAG3). Increased circulating IFNɣ levels were detected, with the highest levels in a heavily pretreated metastatic, microsatellite stable (MSS) colorectal cancer patient leading to a partial tumor response (-52%). FP-1305 is the first macrophage checkpoint inhibitor candidate promoting immune switch with promising tolerability and clinical anti-tumor activity. FP-1305 represents a novel treatment option to provoke immune response especially in non-inflamed tumors. Full safety, pharmacokinetic and efficacy results of MATINS trial (Part 1) will be presented for the first time in a final late breaking abstract. Clinical trial information: 2018-002732-24 .

Designing and evaluating dose-escalation studies made easy: The MoDEsT web app

BACKGROUND/AIMS

Dose-escalation studies are essential in the early stages of developing novel treatments, when the aim is to find a safe dose for administration in humans. Despite their great importance, many dose-escalation studies use study designs based on heuristic algorithms with well-documented drawbacks. Bayesian decision procedures provide a design alternative that is conceptually simple and methodologically sound, but very rarely used in practice, at least in part due to their perceived statistical complexity. There are currently very few easily accessible software implementations that would facilitate their application.

METHODS

We have created MoDEsT, a free and easy-to-use web application for designing and conducting single-agent dose-escalation studies with a binary toxicity endpoint, where the objective is to estimate the maximum tolerated dose. MoDEsT uses a well-established Bayesian decision procedure based on logistic regression. The software has a user-friendly point-and-click interface, makes changes visible in real time, and automatically generates a range of graphs, tables, and reports. It is aimed at clinicians as well as statisticians with limited expertise in model-based dose-escalation designs, and does not require any statistical programming skills to evaluate the operating characteristics of, or implement, the Bayesian dose-escalation design.

RESULTS

MoDEsT comes in two parts: a 'Design' module to explore design options and simulate their operating characteristics, and a 'Conduct' module to guide the dose-finding process throughout the study. We illustrate the practical use of both modules with data from a real phase I study in terminal cancer.

CONCLUSION

Enabling both methodologists and clinicians to understand and apply model-based study designs with ease is a key factor towards their routine use in early-phase studies. We hope that MoDEsT will enable incorporation of Bayesian decision procedures for dose escalation at the earliest stage of clinical trial design, thus increasing their use in early-phase trials.

Phase I trial of WEE1 inhibition with chemotherapy and radiotherapy as adjuvant treatment, and a window of opportunity trial with cisplatin in patients with head and neck cancer: the trial protocol

INTRODUCTION

Patients with head and neck squamous cell carcinoma with locally advanced disease often require multimodality treatment with surgery, radiotherapy and/or chemotherapy. Adjuvant radiotherapy with concurrent chemotherapy is offered to patients with high-risk pathological features postsurgery. While cure rates are improved, overall survival remains suboptimal and treatment has a significant negative impact on quality of life.Cell cycle checkpoint kinase inhibition is a promising method to selectively potentiate the therapeutic effects of chemoradiation. Our hypothesis is that combining chemoradiation with a WEE1 inhibitor will affect the biological response to DNA damage caused by cisplatin and radiation, thereby enhancing clinical outcomes, without increased toxicity. This trial explores the associated effect of WEE1 kinase inhibitor adavosertib (AZD1775).

METHODS AND ANALYSIS

This phase I dose-finding, open-label, multicentre trial aims to determine the highest safe dose of AZD1775 in combination with cisplatin chemotherapy preoperatively (group A) as a window of opportunity trial, and in combination with postoperative cisplatin-based chemoradiation (group B).Modified time-to-event continual reassessment method will determine the recommended dose, recruiting up to 21 patients per group. Primary outcomes are recommended doses with predefined target dose-limiting toxicity probabilities of 25% monitored up to 42 days (group A), and 30% monitored up to 12 weeks (group B). Secondary outcomes are disease-free survival times (groups A and B). Exploratory objectives are evaluation of pharmacodynamic (PD) effects, identification and correlation of potential biomarkers with PD markers of DNA damage, determine rate of resection status and surgical complications for group A; and quality of life in group B.

ETHICS AND DISSEMINATION

Research Ethics Committee, Edgbaston, West Midlands (REC reference 16/WM/0501) initial approval received on 18/01/2017. Results will be disseminated via peer-reviewed publication and presentation at international conferences.

TRIAL REGISTRATION NUMBER

ISRCTN76291951 and NCT03028766.

The poor outcome in high molecular risk, hydroxycarbamide-resistant/intolerant ET is not ameliorated by ruxolitinib

Essential Thrombocythemia (ET) patients at high-risk of thrombosis require cytoreductive treatment, typically with hydroxycarbamide. Many patients are resistant or intolerant to hydroxycarbamide (HC-RES/INT) and are at increased risk of disease progression. MAJIC-ET is a randomized phase 2 study comparing ruxolitinib (RUX) to best available therapy (BAT) in HC-RES/INT ET, which showed no difference between the two arms in rates of hematological response or disease progression. The impact of additional non-MPN driver mutations (NDM) on the risk of disease complications in HC-RES/INT ET patients is unknown. Since the presence of NDM may influence trial outcomes, we expand the primary MAJIC-ET analysis to serially evaluate NDM in MAJIC-ET patients using a targeted myeloid 32-gene panel. NDM at baseline were detected in 30% of patients, most frequently affecting TET2 (11%) followed by TP53 (6.4%) and SF3B1 (6.4%). The presence of a NDM was associated with inferior 4-year transformation-free survival (TFS; 65.4% [95% CI 53.3 – 75%] vs. 82.8% [95% CI 73.2 – 89.1%], p=0.017). Specifically, TP53 (p=0.01) and splicing factor (SF, SF3B1, ZRSR2, SRSF2 ; p<0.001), but not TET2 mutations were associated with reduced TFS which was not mitigated by RUX treatment. Longitudinal analysis identified new mutations in 19.3% of patients; primarily affecting TET2, TP53 and SF3B1 . We report the first comprehensive mutational analysis of HC-RES/INT ET patients and highlight the clinical/prognostic utility of serial mutation analysis for NDM in HC-RES/INT ET, including the importance of SF and TP53 mutations which identify HC-RES/INT ET patients at increased risk of disease transformation.

When to keep it simple - adaptive designs are not always useful

BACKGROUND

Adaptive designs are a wide class of methods focused on improving the power, efficiency and participant benefit of clinical trials. They do this through allowing information gathered during the trial to be used to make changes in a statistically robust manner - the changes could include which treatment arms patients are enrolled to (e.g. dropping non-promising treatment arms), the allocation ratios, the target sample size or the enrolment criteria of the trial. Generally, we are enthusiastic about adaptive designs and advocate their use in many clinical situations. However, they are not always advantageous. In some situations, they provide little efficiency advantage or are even detrimental to the quality of information provided by the trial. In our experience, factors that reduce the efficiency of adaptive designs are routinely downplayed or ignored in methodological papers, which may lead researchers into believing they are more beneficial than they actually are.

MAIN TEXT

In this paper, we discuss situations where adaptive designs may not be as useful, including situations when the outcomes take a long time to observe, when dropping arms early may cause issues and when increased practical complexity eliminates theoretical efficiency gains.

CONCLUSION

Adaptive designs often provide notable efficiency benefits. However, it is important for investigators to be aware that they do not always provide an advantage. There should always be careful consideration of the potential benefits and disadvantages of an adaptive design.

How to design a dose-finding study using the continual reassessment method

INTRODUCTION

The continual reassessment method (CRM) is a model-based design for phase I trials, which aims to find the maximum tolerated dose (MTD) of a new therapy. The CRM has been shown to be more accurate in targeting the MTD than traditional rule-based approaches such as the 3 + 3 design, which is used in most phase I trials. Furthermore, the CRM has been shown to assign more trial participants at or close to the MTD than the 3 + 3 design. However, the CRM's uptake in clinical research has been incredibly slow, putting trial participants, drug development and patients at risk. Barriers to increasing the use of the CRM have been identified, most notably a lack of knowledge amongst clinicians and statisticians on how to apply new designs in practice. No recent tutorial, guidelines, or recommendations for clinicians on conducting dose-finding studies using the CRM are available. Furthermore, practical resources to support clinicians considering the CRM for their trials are scarce.

METHODS

To help overcome these barriers, we present a structured framework for designing a dose-finding study using the CRM. We give recommendations for key design parameters and advise on conducting pre-trial simulation work to tailor the design to a specific trial. We provide practical tools to support clinicians and statisticians, including software recommendations, and template text and tables that can be edited and inserted into a trial protocol. We also give guidance on how to conduct and report dose-finding studies using the CRM.

RESULTS

An initial set of design recommendations are provided to kick-start the design process. To complement these and the additional resources, we describe two published dose-finding trials that used the CRM. We discuss their designs, how they were conducted and analysed, and compare them to what would have happened under a 3 + 3 design.

CONCLUSIONS

The framework and resources we provide are aimed at clinicians and statisticians new to the CRM design. Provision of key resources in this contemporary guidance paper will hopefully improve the uptake of the CRM in phase I dose-finding trials.

Combination Lenalidomide and Azacitidine: A Novel Salvage Therapy in Patients Who Relapse After Allogeneic Stem-Cell Transplantation for Acute Myeloid Leukemia

PURPOSE

Salvage options for patients who relapse after allogeneic stem-cell transplantation (allo-SCT) for acute myeloid leukemia (AML) and myelodysplasia (MDS) remain limited, and novel treatment strategies are required. Both lenalidomide (LEN) and azacitidine (AZA) possess significant antitumor activity effect in AML. Administration of LEN post-transplantation is associated with excessive rates of graft-versus-host disease (GVHD), but AZA has been shown to ameliorate GVHD in murine transplantation models. We therefore examined the tolerability and activity of combined LEN/AZA administration in post-transplantation relapse.

PATIENTS AND METHODS

Twenty-nine patients who had relapsed after allo-SCT for AML (n = 24) or MDS (n = 5) were treated with sequential AZA (75 mg/m² for 7 days) followed by escalating doses of LEN on days 10 to 30. Dose allocation and maximum tolerated dose (MTD) estimation were guided by a modified Bayesian continuous reassessment method (CRM).

RESULTS

Sequential AZA and LEN therapy was well tolerated. The MTD of post-transplantation LEN, in combination with AZA, was determined as 25 mg daily. Three patients developed grade 2 to 4 GVHD. There was no GVHD-related mortality. Seven of 15 (47%) patients achieved a major clinical response after LEN/AZA therapy. CD8+ T cells demonstrated impaired interferon-γ/tumor necrosis factor-α production at relapse, which was not reversed during LEN/AZA administration.

CONCLUSION

We conclude LEN can be administered safely post-allograft in conjunction with AZA, and this combination demonstrates clinical activity in relapsed AML/MDS without reversing biologic features of T-cell exhaustion. The use of a CRM model delivered improved efficiency in MTD assessment and provided additional flexibility. Combined LEN/AZA therapy represents a novel and active salvage therapy in patients who had relapsed post-allograft.

Naturopathic approaches to irritable bowel syndrome: protocol for a prospective observational study in academic teaching clinics

Background

Irritable bowel syndrome (IBS) is a common functional bowel disorder with a worldwide prevalence estimated between 10% and 20%. It has a significant impact on quality of life and societal expense. While there are pharmaceutical options available, few can be reliably recommended. Many IBS sufferers turn to complementary and alternative medicine including naturopathy. Naturopathic approaches to IBS are poorly studied to date.

Methods

We aim to describe naturopathic approaches to IBS as well as establish pilot data on before and after changes in validated IBS instruments. The study will employ a multi-centered, international, prospective, observational, naturalistic design. The uncontrolled before-and-after study will examine the outcomes associated with individualized, whole system naturopathic care as determined by each provider. We will recruit adult patients diagnosed with IBS and presenting to a participating naturopathic academic teaching clinic. Participants’ IBS symptoms will be measured using validated instruments (IBS-SSS and IBS-AR). Quality of life will be measured by using the PROMIS-29 profile. Adverse events will be tracked, as followed for treatment descriptions. Our primary outcomes will be before-and-after differences using week twelve as the primary endpoint. A p values will be set at 0.05, and descriptive and summary data will be presented.

Discussion

This study is designed to plug significant evidence gaps and to gather preliminary evidence to guide the design of a follow-up randomized active controlled trial.

Australia and New Zealand Clinical Trial Registration Number: ACTRN12617001413314

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Development of Clinical Criteria for Functional Assessment to Predict Primary Nonfunction of High-Risk Livers Using Normothermic Machine Perfusion

Increased use of high-risk allografts is critical to meet the demand for liver transplantation. We aimed to identify criteria predicting viability of organs, currently declined for clinical transplantation, using functional assessment during normothermic machine perfusion (NMP). Twelve discarded human livers were subjected to NMP following static cold storage. Livers were perfused with a packed red cell-based fluid at 37°C for 6 hours. Multilevel statistical models for repeated measures were employed to investigate the trend of perfusate blood gas profiles and vascular flow characteristics over time and the effect of lactate-clearing (LC) and non-lactate-clearing (non-LC) ability of the livers. The relationship of lactate clearance capability with bile production and histological and molecular findings were also examined. After 2 hours of perfusion, median lactate concentrations were 3.0 and 14.6 mmol/L in the LC and non-LC groups, respectively. LC livers produced more bile and maintained a stable perfusate pH and vascular flow >150 and 500 mL/minute through the hepatic artery and portal vein, respectively. Histology revealed discrepancies between subjectively discarded livers compared with objective findings. There were minimal morphological changes in the LC group, whereas non-LC livers often showed hepatocellular injury and reduced glycogen deposition. Adenosine triphosphate levels in the LC group increased compared with the non-LC livers. We propose composite viability criteria consisting of lactate clearance, pH maintenance, bile production, vascular flow patterns, and liver macroscopic appearance. These have been tested successfully in clinical transplantation. In conclusion, NMP allows an objective assessment of liver function that may reduce the risk and permit use of currently unused high-risk livers.

Adaptive designs in clinical trials: why use them, and how to run and report them

Adaptive designs can make clinical trials more flexible by utilising results accumulating in the trial to modify the trial's course in accordance with pre-specified rules. Trials with an adaptive design are often more efficient, informative and ethical than trials with a traditional fixed design since they often make better use of resources such as time and money, and might require fewer participants. Adaptive designs can be applied across all phases of clinical research, from early-phase dose escalation to confirmatory trials. The pace of the uptake of adaptive designs in clinical research, however, has remained well behind that of the statistical literature introducing new methods and highlighting their potential advantages. We speculate that one factor contributing to this is that the full range of adaptations available to trial designs, as well as their goals, advantages and limitations, remains unfamiliar to many parts of the clinical community. Additionally, the term adaptive design has been misleadingly used as an all-encompassing label to refer to certain methods that could be deemed controversial or that have been inadequately implemented.We believe that even if the planning and analysis of a trial is undertaken by an expert statistician, it is essential that the investigators understand the implications of using an adaptive design, for example, what the practical challenges are, what can (and cannot) be inferred from the results of such a trial, and how to report and communicate the results. This tutorial paper provides guidance on key aspects of adaptive designs that are relevant to clinical triallists. We explain the basic rationale behind adaptive designs, clarify ambiguous terminology and summarise the utility and pitfalls of adaptive designs. We discuss practical aspects around funding, ethical approval, treatment supply and communication with stakeholders and trial participants. Our focus, however, is on the interpretation and reporting of results from adaptive design trials, which we consider vital for anyone involved in medical research. We emphasise the general principles of transparency and reproducibility and suggest how best to put them into practice.

Granulocyte colony-stimulating factor and autologous CD133-positive stem-cell therapy in liver cirrhosis (REALISTIC): an open-label, randomised, controlled phase 2 trial

BACKGROUND

Results of small-scale studies have suggested that stem-cell therapy is safe and effective in patients with liver cirrhosis, but no adequately powered randomised controlled trials have been done. We assessed the safety and efficacy of granulocyte colony-stimulating factor (G-CSF) and haemopoietic stem-cell infusions in patients with liver cirrhosis.

METHODS

This multicentre, open-label, randomised, controlled phase 2 trial was done in three UK hospitals and recruited patients with compensated liver cirrhosis and MELD scores of 11·0-15·5. Patients were randomly assigned (1:1:1) to receive standard care (control), treatment with subcutaneous G-CSF (lenograstim) 15 μg/kg for 5 days, or treatment with G-CSF for 5 days followed by leukapheresis and intravenous infusion of three doses of CD133-positive haemopoietic stem cells (0·2 × 106 cells per kg per infusion). Randomisation was done by Cancer Research UK Clinical Trials Unit staff with a minimisation algorithm that stratified by trial site and cause of liver disease. The coprimary outcomes were improvement in severity of liver disease (change in MELD) at 3 months and the trend of change in MELD score over time. Analyses were done in the modified intention-to-treat population, which included all patients who received at least one day of treatment. Safety was assessed on the basis of the treatment received. This trial was registered at Current Controlled Trials on Nov 18, 2009; ISRCTN, number 91288089; and the European Clinical Trials Database, number 2009-010335-41.

FINDINGS

Between May 18, 2010, and Feb 26, 2015, 27 patients were randomly assigned to the standard care, 26 to the G-CSF group, and 28 to the G-CSF plus stem-cell infusion group. Median change in MELD from day 0 to 90 was -0·5 (IQR -1·5 to 1·1) in the standard care group, -0·5 (-1·7 to 0·5) in the G-CSF group, and -0·5 (-1·3 to 1·0) in the G-CSF plus stem-cell infusion group. We found no evidence of differences between the treatment groups and control group in the trends of MELD change over time (p=0·55 for the G-CSF group vs standard care and p=0·75 for the G-CSF plus stem-cell infusion group vs standard care). Serious adverse events were more frequent the in G-CSF and stem-cell infusion group (12 [43%] patients) than in the G-CSF (three [11%] patients) and standard care (three [12%] patients) groups. The most common serious adverse events were ascites (two patients in the G-CSF group and two patients in the G-CSF plus stem-cell infusion group, one of whom was admitted to hospital with ascites twice), sepsis (four patients in the G-CSF plus stem-cell infusion group), and encephalopathy (three patients in the G-CSF plus stem-cell infusion group, one of whom was admitted to hospital with encephalopathy twice). Three patients died, including one in the standard care group (variceal bleed) and two in the G-CSF and stem-cell infusion group (one myocardial infarction and one progressive liver disease).

INTERPRETATION

G-CSF with or without haemopoietic stem-cell infusion did not improve liver dysfunction or fibrosis and might be associated with increased frequency of adverse events compared with standard care.

FUNDING

National Institute of Health Research, The Sir Jules Thorn Charitable Trust.

Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children

BACKGROUND

Antibiotics can disturb gastrointestinal microbiota which may lead to reduced resistance to pathogens such as Clostridium difficile (C. difficile). Probiotics are live microbial preparations that, when administered in adequate amounts, may confer a health benefit to the host, and are a potential C. difficile prevention strategy. Recent clinical practice guidelines do not recommend probiotic prophylaxis, even though probiotics have the highest quality evidence among cited prophylactic therapies.

OBJECTIVES

To assess the efficacy and safety of probiotics for preventing C.difficile-associated diarrhea (CDAD) in adults and children.

SEARCH METHODS

We searched PubMed, EMBASE, CENTRAL, and the Cochrane IBD Group Specialized Register from inception to 21 March 2017. Additionally, we conducted an extensive grey literature search.

SELECTION CRITERIA

Randomized controlled (placebo, alternative prophylaxis, or no treatment control) trials investigating probiotics (any strain, any dose) for prevention of CDAD, or C. difficile infection were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors (independently and in duplicate) extracted data and assessed risk of bias. The primary outcome was the incidence of CDAD. Secondary outcomes included detection of C. difficile infection in stool, adverse events, antibiotic-associated diarrhea (AAD) and length of hospital stay. Dichotomous outcomes (e.g. incidence of CDAD) were pooled using a random-effects model to calculate the risk ratio (RR) and corresponding 95% confidence interval (95% CI). We calculated the number needed to treat for an additional beneficial outcome (NNTB) where appropriate. Continuous outcomes (e.g. length of hospital stay) were pooled using a random-effects model to calculate the mean difference and corresponding 95% CI. Sensitivity analyses were conducted to explore the impact of missing data on efficacy and safety outcomes. For the sensitivity analyses, we assumed that the event rate for those participants in the control group who had missing data was the same as the event rate for those participants in the control group who were successfully followed. For the probiotic group, we calculated effects using the following assumed ratios of event rates in those with missing data in comparison to those successfully followed: 1.5:1, 2:1, 3:1, and 5:1. To explore possible explanations for heterogeneity, a priori subgroup analyses were conducted on probiotic species, dose, adult versus pediatric population, and risk of bias as well as a post hoc subgroup analysis on baseline risk of CDAD (low 0% to 2%; moderate 3% to 5%; high > 5%). The overall quality of the evidence supporting each outcome was independently assessed using the GRADE criteria.

MAIN RESULTS

Thirty-nine studies (9955 participants) met the eligibility requirements for our review. Overall, 27 studies were rated as either high or unclear risk of bias. A complete case analysis (i.e. participants who completed the study) among trials investigating CDAD (31 trials, 8672 participants) suggests that probiotics reduce the risk of CDAD by 60%. The incidence of CDAD was 1.5% (70/4525) in the probiotic group compared to 4.0% (164/4147) in the placebo or no treatment control group (RR 0.40, 95% CI 0.30 to 0.52; GRADE = moderate). Twenty-two of 31 trials had missing CDAD data ranging from 2% to 45%. Our complete case CDAD results proved robust to sensitivity analyses of plausible and worst-plausible assumptions regarding missing outcome data and results were similar whether considering subgroups of trials in adults versus children, inpatients versus outpatients, different probiotic species, lower versus higher doses of probiotics, or studies at high versus low risk of bias. However, in a post hoc analysis, we did observe a subgroup effect with respect to baseline risk of developing CDAD. Trials with a baseline CDAD risk of 0% to 2% and 3% to 5% did not show any difference in risk but trials enrolling participants with a baseline risk of > 5% for developing CDAD demonstrated a large 70% risk reduction (interaction P value = 0.01). Among studies with a baseline risk > 5%, the incidence of CDAD in the probiotic group was 3.1% (43/1370) compared to 11.6% (126/1084) in the control group (13 trials, 2454 participants; RR 0.30, 95% CI 0.21 to 0.42; GRADE = moderate). With respect to detection of C. difficile in the stool pooled complete case results from 15 trials (1214 participants) did not show a reduction in infection rates. C. difficile infection was 15.5% (98/633) in the probiotics group compared to 17.0% (99/581) in the placebo or no treatment control group (RR 0.86, 95% CI 0.67 to 1.10; GRADE = moderate). Adverse events were assessed in 32 studies (8305 participants) and our pooled complete case analysis indicates probiotics reduce the risk of adverse events by 17% (RR 0.83, 95% CI 0.71 to 0.97; GRADE = very low). In both treatment and control groups the most common adverse events included abdominal cramping, nausea, fever, soft stools, flatulence, and taste disturbance.

AUTHORS' CONCLUSIONS

Based on this systematic review and meta-analysis of 31 randomized controlled trials including 8672 patients, moderate certainty evidence suggests that probiotics are effective for preventing CDAD (NNTB = 42 patients, 95% CI 32 to 58). Our post hoc subgroup analyses to explore heterogeneity indicated that probiotics are effective among trials with a CDAD baseline risk >5% (NNTB = 12; moderate certainty evidence), but not among trials with a baseline risk ≤5% (low to moderate certainty evidence). Although adverse effects were reported among 32 included trials, there were more adverse events among patients in the control groups. The short-term use of probiotics appears to be safe and effective when used along with antibiotics in patients who are not immunocompromised or severely debilitated. Despite the need for further research, hospitalized patients, particularly those at high risk of CDAD, should be informed of the potential benefits and harms of probiotics.

Dose Transition Pathways: The Missing Link Between Complex Dose-Finding Designs and Simple Decision-Making

The ever-increasing pace of development of novel therapies mandates efficient methodologies for assessment of their tolerability and activity. Evidence increasingly support the merits of model-based dose-finding designs in identifying the recommended phase II dose compared with conventional rule-based designs such as the 3 + 3 but despite this, their use remains limited. Here, we propose a useful tool, dose transition pathways (DTP), which helps overcome several commonly faced practical and methodologic challenges in the implementation of model-based designs. DTP projects in advance the doses recommended by a model-based design for subsequent patients (stay, escalate, de-escalate, or stop early), using all the accumulated information. After specifying a model with favorable statistical properties, we utilize the DTP to fine-tune the model to tailor it to the trial's specific requirements that reflect important clinical judgments. In particular, it can help to determine how stringent the stopping rules should be if the investigated therapy is too toxic. Its use to design and implement a modified continual reassessment method is illustrated in an acute myeloid leukemia trial. DTP removes the fears of model-based designs as unknown, complex systems and can serve as a handbook, guiding decision-making for each dose update. In the illustrated trial, the seamless, clear transition for each dose recommendation aided the investigators' understanding of the design and facilitated decision-making to enable finer calibration of a tailored model. We advocate the use of the DTP as an integral procedure in the co-development and successful implementation of practical model-based designs by statisticians and investigators. Clin Cancer Res; 23(24); 7440-7. ©2017 AACR.

Viability testing and transplantation of marginal livers (VITTAL) using normothermic machine perfusion: study protocol for an open-label, non-randomised, prospective, single-arm trial

INTRODUCTION

The use of marginal or extended criteria donor livers is increasing. These organs carry a greater risk of initial dysfunction and early failure, as well as inferior long-term outcomes. As such, many are rejected due to a perceived risk of use and use varies widely between centres. Ex situ normothermic machine perfusion of the liver (NMP-L) may enable the safe transplantation of organs that meet defined objective criteria denoting their high-risk status and are currently being declined for use by all the UK transplant centres.

METHODS AND ANALYSIS

Viability testing and transplantation of marginal livers is an open-label, non-randomised, prospective, single-arm trial designed to determine whether currently unused donor livers can be salvaged and safely transplanted with equivalent outcomes in terms of patient survival. The procured rejected livers must meet predefined criteria that objectively denote their marginal condition. The liver is subjected to NMP-L following a period of static cold storage. Organs metabolising lactate to ≤2.5 mmol/L within 4 hours of the perfusion commencing in combination with two or more of the following parameters-bile production, metabolism of glucose, a hepatic arterial flow rate ≥150 mL/min and a portal venous flow rate ≥500 mL/min, a pH ≥7.30 and/or maintain a homogeneous perfusion-will be considered viable and transplanted into a suitable consented recipient. The coprimary outcome measures are the success rate of NMP-L to produce a transplantable organ and 90-day patient post-transplant survival.

ETHICS AND DISSEMINATION

The protocol was approved by the National Research Ethics Service (London-Dulwich Research Ethics Committee, 16/LO/1056), the Medicines and Healthcare Products Regulatory Agency and is endorsed by the National Health Service Blood and Transplant Research, Innovation and Novel Technologies Advisory Group. The findings of this trial will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT02740608; Pre-results.

Ruxolitinib vs best available therapy for ET intolerant or resistant to hydroxycarbamide

Treatments for high-risk essential thrombocythemia (ET) address thrombocytosis, disease-related symptoms, as well as risks of thrombosis, hemorrhage, transformation to myelofibrosis, and leukemia. Patients resistant/intolerant to hydroxycarbamide (HC) have a poor outlook. MAJIC (ISRCTN61925716) is a randomized phase 2 trial of ruxolitinib (JAK1/2 inhibitor) vs best available therapy (BAT) in ET and polycythemia vera patients resistant or intolerant to HC. Here, findings of MAJIC-ET are reported, where the modified intention-to-treat population included 58 and 52 patients randomized to receive ruxolitinib or BAT, respectively. There was no evidence of improvement in complete response within 1 year reported in 27 (46.6%) patients treated with ruxolitinib vs 23 (44.2%) with BAT (P = .40). At 2 years, rates of thrombosis, hemorrhage, and transformation were not significantly different; however, some disease-related symptoms improved in patients receiving ruxolitinib relative to BAT. Molecular responses were uncommon; there were 2 complete molecular responses (CMR) and 1 partial molecular response in CALR-positive ruxolitinib-treated patients. Transformation to myelofibrosis occurred in 1 CMR patient, presumably because of the emergence of a different clone, raising questions about the relevance of CMR in ET patients. Grade 3 and 4 anemia occurred in 19% and 0% of ruxolitinib vs 0% (both grades) in the BAT arm, and grade 3 and 4 thrombocytopenia in 5.2% and 1.7% of ruxolitinib vs 0% (both grades) of BAT-treated patients. Rates of discontinuation or treatment switching did not differ between the 2 trial arms. The MAJIC-ET trial suggests that ruxolitinib is not superior to current second-line treatments for ET. This trial was registered at www.isrctn.com as #ISRCTN61925716.

Embracing model-based designs for dose-finding trials

BACKGROUND

Dose-finding trials are essential to drug development as they establish recommended doses for later-phase testing. We aim to motivate wider use of model-based designs for dose finding, such as the continual reassessment method (CRM).

METHODS

We carried out a literature review of dose-finding designs and conducted a survey to identify perceived barriers to their implementation.

RESULTS

We describe the benefits of model-based designs (flexibility, superior operating characteristics, extended scope), their current uptake, and existing resources. The most prominent barriers to implementation of a model-based design were lack of suitable training, chief investigators' preference for algorithm-based designs (e.g., 3+3), and limited resources for study design before funding. We use a real-world example to illustrate how these barriers can be overcome.

CONCLUSIONS

There is overwhelming evidence for the benefits of CRM. Many leading pharmaceutical companies routinely implement model-based designs. Our analysis identified barriers for academic statisticians and clinical academics in mirroring the progress industry has made in trial design. Unified support from funders, regulators, and journal editors could result in more accurate doses for later-phase testing, and increase the efficiency and success of clinical drug development. We give recommendations for increasing the uptake of model-based designs for dose-finding trials in academia.

Implementing the EffTox dose-finding design in the Matchpoint trial

BACKGROUND

The Matchpoint trial aims to identify the optimal dose of ponatinib to give with conventional chemotherapy consisting of fludarabine, cytarabine and idarubicin to chronic myeloid leukaemia patients in blastic transformation phase. The dose should be both tolerable and efficacious. This paper describes our experience implementing EffTox in the Matchpoint trial.

METHODS

EffTox is a Bayesian adaptive dose-finding trial design that jointly scrutinises binary efficacy and toxicity outcomes. We describe a nomenclature for succinctly describing outcomes in phase I/II dose-finding trials. We use dose-transition pathways, where doses are calculated for each feasible set of outcomes in future cohorts. We introduce the phenomenon of dose ambivalence, where EffTox can recommend different doses after observing the same outcomes. We also describe our experiences with outcome ambiguity, where the categorical evaluation of some primary outcomes is temporarily delayed.

RESULTS

We arrived at an EffTox parameterisation that is simulated to perform well over a range of scenarios. In scenarios where dose ambivalence manifested, we were guided by the dose-transition pathways. This technique facilitates planning, and also helped us overcome short-term outcome ambiguity.

CONCLUSIONS

EffTox is an efficient and powerful design, but not without its challenges. Joint phase I/II clinical trial designs will likely become increasingly important in coming years as we further investigate non-cytotoxic treatments and streamline the drug approval process. We hope this account of the problems we faced and the solutions we used will help others implement this dose-finding clinical trial design.

TRIAL REGISTRATION

Matchpoint was added to the European Clinical Trials Database ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2012-005629-65/GB ) on 2013-12-30.

Phase III randomised controlled trial (RCT) comparing alternative regimens for escalating treatment of intermediate and high-risk oropharyngeal cancer (CompARE)

TPS6091

Background: Patients with intermediate and high-risk oropharyngeal cancer (OPC) have poorer response to standard treatment and poorer overall survival compared to low-risk OPC. The CompARE trial is designed to test alternative approaches to intensification of treatment for these patients to improve survival. Methods: CompARE is a pragmatic phase III open-label multicenter RCT with an adaptive multi-arm multi-stage design. Eligible OPC patients include those with; HPV negative, T1-T4, N1-N3 or T3-4, N0 or HPV positive current smokers (or ≥ 10 pack years previous smoking history) with T1-T4, N2b-N3. The primary outcome measure is overall survival. Secondary outcome measures include quality of life, toxicity, swallowing outcomes, feeding tube incidence, surgical complications and cost-effectiveness. The trial is powered to detect a hazard ratio of 0.69 (an improvement of 10% in OS at 3-years) requiring 128 control events. It is estimated that the study will take 6.5 years to recruit sufficient patients to experience the number of events needed. Planned interim futility analyses using event-free survival (EFS) will be performed when 70 and 114 control EFS events have occurred. Current treatment arms are; (1) control: standard treatment of 3-weekly cisplatin 100mg/m2 or weekly 40mg/m2 with Intensity Modulated Radiotherapy (IMRT) using 70Gy in 35F +/- neck dissection determined by clinical and radiological assessment 3-months post treatment. (3) IMRT 64Gy in 25F + cisplatin 100mg/m2 day 1 of week 1 and week 5 or weekly 40mg/m2+/- neck dissection as per standard treatment. (4) Resection of primary + selective neck dissection followed by standard treatment. (5) One cycle of induction durvalumab 1500mg followed by standard treatment then durvalumab 1500mg every four weeks for a total of 6 months. Recruitment to arm (2) involving induction chemotherapy from the original protocol is suspended. Since July 2015, 42 patients have been randomised with 16 sites open to recruitment. The Data Monitoring Committee last reviewed progress and conduct of the trial in September 2016 and recommended continuation. ISRCTN Number: 41478539, CRUK CRUK/13/026 Clinical trial information: 41478539.