Early closure of European Pimagedine trial. Steering Committee. Safety Committee

Small molecule inhibiting microglial nitric oxide release could become a potential treatment for neuroinflammation

Microglia are the immune effector cells of the central nervous system (CNS) and react to pathologic events with a complex process including the release of nitric oxide (NO). NO is a free radical, which is toxic for all cells at high concentrations. To target an exaggerated NO release, we tested a library of 16 544 chemical compounds for their effect on lipopolysaccharide (LPS)-induced NO release in cell line and primary neonatal microglia. We identified a compound (C1) which significantly reduced NO release in a dose-dependent manner, with a low IC50 (252 nM) and no toxic side effects in vitro or in vivo. Target finding strategies such as in silico modelling and mass spectroscopy hint towards a direct interaction between C1 and the nitric oxide synthase making C1 a great candidate for specific intra-cellular interaction with the NO producing machinery.

Characteristics of Ophthalmology Trials Registered in ClinicalTrials.gov, 2007-2018

PURPOSE

To perform a comprehensive analysis of characteristics of ophthalmology trials registered in ClinicalTrials.gov.

DESIGN

Cross-sectional study.

METHODS

All 4,203 ophthalmologic clinical trials registered on ClinicalTrials.gov between October 1, 2007, and April 30, 2018, were identified by using medical subject headings (MeSH). Disease condition terms were verified by manual review. Trial characteristics were assessed through frequency calculations. Hazard ratios and 95% confidence intervals were determined for characteristics associated with early discontinuation.

RESULTS

The majority of trials were multiarmed (73.6%), single-site (69.4%), randomized (64.8%), and had <100 enrollees (66.3%). A total of 33% used a data-monitoring committee (DMC), and 50.6% incorporated blinding. Other groups (51.6%) were funded by industry, whereas 2.6% were funded by the US National Institutes of Health (NIH). NIH trials were significantly more likely to address oncologic (NIH = 15.5%, Other = 3%, Industry = 1.5%; P < 0.001) or pediatric disease (NIH = 20.9%, Other = 5.9%, Industry = 1.4%; P < 0.001). Industry-sponsored trials (69.6% of phase 3 trials) were significantly more likely to be randomized (Industry = 68.7%, NIH = 58.9%, Other = 60.8%; P < 0.001) and blinded (Industry = 57.2%, NIH = 42.7%, Other = 43.5%; P < 0.001). A total of 359 trials (8.5%) were discontinued early, and 530 trials (12.6%) had unknown status. Trials were less likely to be discontinued if funded by sources other than industry (hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.55-0.95; P = 0.021) and/or had a DMC (HR, 0.71; 95% CI, 0.55-0.92; P = 0.010).

CONCLUSIONS

Ophthalmology trials in the past decade reveal heterogeneity across study funding sources. NIH trials were more likely to support historically underfunded subspecialties, whereas Industry trials were more likely to face early discontinuation. These trends emphasize the importance of carefully monitored and methodologically sound trials with deliberate funding allocation.

Implications of product withdrawal on a post-approval pragmatic trial: The VOLUME study experience

INTRODUCTION

Many clinical trials terminate early due to safety and efficacy concerns, and less often due to unexpected "positive" findings. However, early termination of post-approval (Phase IV) pragmatic randomized trials for commercial reasons is less frequent, may be more complex, and may require added flexibility in closure methods, including short term follow-up. VOLUME was a randomized, open-label, post-approval pragmatic clinical trial (PCT) or large simple trial that terminated early due to product withdrawal. The aim of this paper is to describe circumstances unique to post-approval PCTs that may require a closure amendment rather than immediate study termination, and our recommendations for operational study closure in these circumstances. We use the VOLUME case study throughout to provide a practical example.

METHODS

Study closeout considerations at the study level include: notifying external governance bodies, e.g., data monitoring committees (DMC), and scientific steering committees (SSC); executing a study closure amendment; notifying and training of study physicians; and institutional review board (IRB)/ethics committee (EC) approvals. Study closure considerations at the patient level focus on patient safety and include: patient notification, efficient transition to alternative treatments, the need for re-consenting; and drug supply shortages.

CONCLUSIONS

Early study closeout logistics require careful analysis, detailed planning, and close coordination, and are ideally considered at the study planning phase. Lessons learned from the VOLUME closeout should help other researchers devise contingencies when terminating post approval pragmatic trials that utilize a marketed product.ClinicalTrials.gov: NCT00359801.

Neuropathic pain: mechanisms of development, principles of diagnostics and treatment

Neuropathic pain is a pain caused by a disease or focal damage to the somatosensory nervous system. The prevalence of chronic pain with neuropathic features in different countries is estimated at 7–10 %. Damages to the nervous system can occur at the level of peripheral nerves, plexus and dorsal roots (peripheral neuropathic pain) or spinal cord and brain (central neuropathic pain). Neuropathic pain is based on pathological activation of pain pathways. Neuropathic pain occurs with diabetic polyneuropathy more often than with all polyneuropathies of another etiology. Hyperglycemia is the major cause of chronic diabetes mellitus and its progression. Since the cause of pain can rarely be cured, treatment is usually symptomatic. Neuropathic pain is generally poorly controlled by analgesics. NB management is started with conservative pharmacotherapy before applying invasive analgesia. Although there are many drugs that can be used in patients with DPN, monotherapy can not always stop pain syndrome. In addition, the patient may not tolerate the full therapeutic dose of the drug. All this dictates the need for combination therapy.

Retinylamine Benefits Early Diabetic Retinopathy in Mice

Recent evidence suggests an important role for outer retinal cells in the pathogenesis of diabetic retinopathy (DR). Here we investigated the effect of the visual cycle inhibitor retinylamine (Ret-NH2) on the development of early DR lesions. Wild-type (WT) C57BL/6J mice (male, 2 months old when diabetes was induced) were made diabetic with streptozotocin, and some were given Ret-NH2 once per week. Lecithin-retinol acyltransferase (LRAT)-deficient mice and P23H mutant mice were similarly studied. Mice were euthanized after 2 (WT and Lrat(-/-)) and 8 months (WT) of study to assess vascular histopathology, accumulation of albumin, visual function, and biochemical and physiological abnormalities in the retina. Non-retinal effects of Ret-NH2 were examined in leukocytes treated in vivo. Superoxide generation and expression of inflammatory proteins were significantly increased in retinas of mice diabetic for 2 or 8 months, and the number of degenerate retinal capillaries and accumulation of albumin in neural retina were significantly increased in mice diabetic for 8 months compared with nondiabetic controls. Administration of Ret-NH2 once per week inhibited capillary degeneration and accumulation of albumin in the neural retina, significantly reducing diabetes-induced retinal superoxide and expression of inflammatory proteins. Superoxide generation also was suppressed in Lrat(-/-) diabetic mice. Leukocytes isolated from diabetic mice treated with Ret-NH2 caused significantly less cytotoxicity to retinal endothelial cells ex vivo than did leukocytes from control diabetics. Administration of Ret-NH2 once per week significantly inhibited the pathogenesis of lesions characteristic of early DR in diabetic mice. The visual cycle constitutes a novel target for inhibition of DR.

Unsuccessful trial accrual and human subjects protections: an empirical analysis of recently closed trials

BACKGROUND

Ethical evaluation of risk-benefit in clinical trials is premised on the achievability of resolving research questions motivating an investigation.

OBJECTIVE

To determine the fraction and number of patients enrolled in trials that were at risk of not meaningfully addressing their primary research objective due to unsuccessful patient accrual.

METHODS

We used the National Library of Medicine clinical trial registry to capture all initiated phases 2 and 3 intervention clinical trials that were registered as closed in 2011. We then determined the number that had been terminated due to unsuccessful accrual and the number that had closed after less than 85% of the target number of human subjects had been enrolled. Five factors were tested for association with unsuccessful accrual.

RESULTS

Of 2579 eligible trials, 481 (19%) either terminated for failed accrual or completed with less than 85% expected enrolment, seriously compromising their statistical power. Factors associated with unsuccessful accrual included greater number of eligibility criteria (p = 0.013), non-industry funding (25% vs 16%, p < 0.0001), earlier trial phase (23% vs 16%, p < 0.0001), fewer number of research sites at trial completion (p < 0.0001) and at registration (p < 0.0001), and an active (non-placebo) comparator (23% vs 16%, p < 0.001).

CONCLUSION

A total of 48,027 patients had enrolled in trials closed in 2011 who were unable to answer the primary research question meaningfully. Ethics bodies, investigators, and data monitoring committees should carefully scrutinize trial design, recruitment plans, and feasibility of achieving accrual targets when designing and reviewing trials, monitor accrual once initiated, and take corrective action when accrual is lagging.

Money and morals: ending clinical trials for financial reasons

Too often, biopharmaceutical companies stop their clinical trials solely for financial reasons. In this chapter, we discuss this phenomenon against the backdrop of a 2011 decision by Geron Corporation to abandon its stem cell clinical trial for spinal cord injury (SCI), the preliminary results of which were released in May 2014. We argue that the resultant harms are widespread and are different in nature from the consequences of stopping trials for scientific or medical reasons. We examine the ethical and social effects that arise from such decisions and discuss them in light of ethical frameworks, including duties of individual stakeholders and corporate sponsors. We offer ways that sponsors and clinical sites can ensure that trials are responsibly started, and once started adequately protect the interests of participants. We conclude with recommendations that industry sponsors of clinical trials should adopt in order to advance a collective and patient-centered research ethic.

Would tirofiban have been shown non-inferior to abciximab had the TENACITY trial not been terminated for financial reasons?

OBJECTIVES

To investigate whether tirofiban would have been non-inferior to abciximab had the trial completed enrollment and place the termination of this trial in a broader research ethics context.

BACKGROUND

TENACITY was terminated by the sponsor for financial reasons. At the time, event rates for the 2 treatment arms were unknown.

METHODS

TENACITY was designed to compare tirofiban with abciximab in approximately 8,000 patients; however, enrollment was terminated after 383 (4.8%) patients. The primary end-point was a composite of 30-day death, myocardial infarction, and urgent target vessel revascularization. Non-inferiority was defined as the likelihood that tirofiban would preserve at least 50% of the ability of abciximab to reduce the primary end-point at 30 days, based on abciximab's demonstrated ability to reduce such events by 43% (relative risk, 0.573; 95% confidence interval [CI], 0.507-0.648; P < 0.001). To determine the probability of non-inferiority given the patients already enrolled, a Bayesian approach was used.

RESULTS

The primary composite end-point occurred in 8.8% of patients randomized to abciximab versus 6.9% receiving high-bolus-dose tirofiban (odds ratio, 0.77; 95% CI, 0.37-1.64). The estimated conditional power for the test that tirofiban would be non-inferior to abciximab if all patients been enrolled is 93.7%. Using the estimated predictive power method, the likelihood was 84.8%.

CONCLUSIONS

TENACITY was well powered to identify non-inferiority with tirofiban versus abciximab, and the patients enrolled strengthened the probability that this would have been the outcome had the trial been completed. When a clinical trial is terminated solely for financial reasons, it is incumbent upon the sponsor to provide proper patient follow-up and publication of the findings.

Clinical potential of advanced glycation end-product inhibitors in diabetes mellitus

Non-enzymatic accumulation of advanced glycation end-products (AGE) is to some extent a physiologic consequence of tissue aging. On the other hand, circulating AGE and tissue deposits mark the course of diabetes mellitus as well as a variety of other vascular or degenerative diseases. AGE generation is paralleled by oxidative damage and lipid peroxidation within target tissue, with features of inflammation through the involvement of monocytes/macrophages expressing receptors for glycated macromolecules. Over the past 15 years, a wealth of data concerning the pharmacology of AGE have been gathered through animal and human investigations, targeting their likely contribution to the progression of diabetic and non-diabetic vascular damage. Several agents have been shown to interfere with the formation of AGE or AGE precursors, bind to tissue receptors, or promote breakdown of deposits. The first and most studied inhibitor, aminoguanidine, has shown extensive beneficial effects in experimental models of diabetic vascular damage, recently entering phase I-III clinical investigation. Newer anti-AGE agents include pyridoxamine and the so-called 'amadorins', cross-link breakers, AGE binders and receptor antagonists.

The role of the data safety and monitoring committee in stroke trials

There are many good reasons why any human experiment should have appropriate oversight. In clinical trials, the data safety and monitoring committee (DSMC) serves to protect the interests of the patients. In stroke trials, its members usually together represent a broad expertise in neurology, internal medicine, cardiology and biostatistics. Independency and integrity are key words, especially in the relationship to the sponsor of the trial. The DSMC members should have no long-term financial strings to the sponsor, and they should not be personally involved in patient recruitment and evaluation. The DSMC provides recommendations to the steering committee of the trial on whether to continue or to stop patient recruitment and on protocol amendments that may be necessary to protect the safety of the patients.

Potential new medical therapies for diabetic retinopathy: protein kinase C inhibitors

PURPOSE

To review the evidence supporting a role for the beta (beta) isoform of protein kinase C (PKC) in the pathogenesis of diabetic retinopathy and the possible therapeutic benefit of inhibiting this enzyme.

DESIGN

Brief literature review of research suggesting the potential use for systemic inhibitors of the beta isoform of PKC as a medical therapy to prevent the progression of diabetic retinopathy. Brief consideration is given to previous, primarily clinical, studies dealing with other therapies for this disease.

RESULTS

Kinases transfer the terminal, "high energy," phosphate group of ATP to a site on a target protein, thereby activating the protein, which may be an enzyme, cell membrane receptor, or ion transport channel. The PKC family is a group of such enzymes that require specific activator molecules, including diacylglycerol, whose intracellular concentration is substantially increased during the hyperglycemia of diabetes. Protein kinase Cbeta is present at high levels in the retina. Increased activation of this enzyme, perhaps by producing tissue hypoxia, leads to increased expression of vascular endothelial growth factor, a mitogen that increases proliferation of vascular endothelial cells leading to neovascularization and enhances breakdown of the blood-retinal barrier, perhaps resulting in macular edema.

CONCLUSIONS

By interfering with the above biochemical pathways, PKC inhibitors may retard or prevent the development and progression of diabetic retinopathy. Because members of the PKC family are found throughout the body, a generalized inhibitor is likely to be toxic. However, an inhibitor specific for PKCbeta may act effectively within the retina and have a favorable toxicity profile. Two phase III randomized controlled clinical trials of such an inhibitor are now in progress, attempting to evaluate the efficacy of this approach to preventing the progression, or inducing regression, of "nonclinically significant" diabetic macular edema and of severe nonproliferative diabetic retinopathy.

Effect of chronic aminoguanidine treatment on age-related glycation, glycoxidation, and collagen cross-linking in the Fischer 344 rat

Aminoguanidine (AG) is an inhibitor of protein modification by the advanced Maillard reaction. We evaluated its effects in preventing age-related collagen cross-linking, glycation, and glycoxidation in Fischer 344 rats by administering the drug in their drinking water at 1 g/l from the time they were 6 months until they were 24 months of age. Body weight and food and water consumption were consistently recorded throughout the study. Plasma glucose was measured by the glucose oxidase method, and collagen cross-linking was assessed by tail tendon break time (TBT) in urea. Glycation (furosine) and glycoxidation (pentosidine and carboxymethyllysine) were assessed by high-performance liquid chromatography in acid hydrolysates of skin and tendon collagen. Water consumption dramatically increased (p <.0001) after 20 months of age and was accelerated in the control versus AG-treated rats (p <.0001). Plasma glucose increased approximately 20% at age 19 months in both groups (p <.0001). TBT, glycation, and glycoxidation all increased significantly (p <.0001) with age. However, except for a modest decrease of TBT at all ages that approached significance (p =.077), AG had no effect on collagen glycation or glycoxidation. These results are important because they suggest that alpha,beta-dicarbonyl compounds that can be trapped by aminoguanidine do not play a major role in collagen aging in the rat. Instead, post-Amadori pathways involving oxidative or nonoxidative fragmentation of the Amadori product emerge as the more likely mechanism of collagen cross-linking in aging.