Systematic review of interventional sickle cell trials registered in ClinicalTrials.gov

Cardiac Toxicity in the Treatment of Light Chain Amyloidosis: Systematic Review of Clinical Studies

BACKGROUND

Light chain amyloidosis (AL) is a progressive and a fatal disease that primarily affects cardiac tissue. Although the current approach to anti-amyloidosis treatments has managed to reduce amyloidosis morbimortality, the dynamics of cardiac adverse events are unknown.

OBJECTIVE

to provide evidence about reported cardiac toxicity during treatment of AL amyloidosis through a systematic review of the literature.

METHODS

A search was performed for registered clinical trials on ClinicalTrials.gov filtered for AL amyloidosis up to December 31, 2022. Studies were filtered by those that reported intervention in patients with AL amyloidosis and that had reported adverse events. The type of study, the intervention performed, and the frequency of reported cardiac adverse events were discriminated from each trial.

RESULTS

25 clinical trials were analyzed, representing a population of 1,542 patients, among whom 576 (38.95%) adverse events were reported, 326 being serious (SAE) and 242 nonserious (nSAE). The most frequent SAEs were cardiac failure, atrial fibrillation, and cardiac arrest, while the most frequent nSAEs were palpitations, atrial fibrillation, and sinus tachycardia.

CONCLUSION

cardiac toxicity during treatment for amyloidosis seems common, and it is important to evaluate the relationship of therapies with its occurrence.

Using the consolidated framework for implementation research to identify recruitment barriers and targeted strategies for a shared decision-making randomized clinical trial in pediatric sickle cell disease

BACKGROUND/AIMS

Recruitment is often a barrier in clinical trials that include minoritized populations, such as individuals with sickle cell disease. In the United States, the majority of people with sickle cell disease identify as Black or African American. In sickle cell disease, 57% of the United States trials that ended early did so due to low enrollment. Thus, there is a need for interventions that improve trial enrollment in this population. After lower-than-expected recruitment during the first 6 months of the Engaging Parents of Children with Sickle Cell Anemia and their Providers in Shared-Decision-Making for Hydroxyurea trial, a multi-site study for young children with sickle cell disease, we collected data to understand barriers and used the Consolidated Framework for Implementation Research to categorize them and guide the development of targeted strategies.

METHODS

Study staff used screening logs and coordinator and principal investigator calls to identify recruitment barriers that were then mapped onto Consolidated Framework for Implementation Research constructs. Targeted strategies were implemented during Months 7-13. Recruitment and enrollment data were summarized before (Months 1-6) and during the implementation period (Months 7-13).

RESULTS

During the first 13 months, 60 caregivers (M = 30.65 years; SD = 6.35) enrolled in the trial. Most caregivers primarily self-identified as female (n = 54, 95%) and African American or Black (n = 51, 90%). Recruitment barriers mapped onto three Consolidated Framework for Implementation Research constructs: (1) Process barriers (i.e. no identified "site champion" and poor recruitment planning at several sites); (2) Inner setting barriers (i.e. limited communication, low relative study priority at several sites); and (3) Outer setting barriers (i.e. poor patient attendance at clinic appointments). Targeted strategies to improve recruitment included (1) principal investigator site visits and retraining on recruitment procedures to address process barriers; (2) increased frequency of communication through all coordinator, site principal investigator, and individual site calls to address inner setting barriers; and (3) development and implementation of no-show procedures for clinic appointments to address outer setting barriers. After implementation of the recruitment strategies, the number of caregivers identified for pre-screening increased from 54 to 164, and enrollment more than tripled from 14 to 46 caregiver participants.

CONCLUSION

Consolidated Framework for Implementation Research constructs guided the development of targeted strategies that increased enrollment. This reflective process reframes recruitment challenges as the responsibility of the research team rather than characterizing minoritized populations as "difficult" or "hard to reach." Future trials including patients with sickle cell disease and minoritized populations may benefit from this approach.

Palatability and Acceptability of Flaxseed-Supplemented Foods in Children with Sickle Cell Disease

Omega-3 fatty acids (w3FAs) have demonstrated benefits in several inflammatory disease states; however, limited research has been conducted in sickle cell disease (SCD). While marine-based w3FAs are used, their strong odor and taste are a barrier to long-term use. Plant-based sources, especially those in whole foods, may circumvent this barrier. We tested whether flaxseed (rich source of w3FAs) was acceptable to children with SCD. A cross-sectional tasting trial of flaxseed added to baked products (cookies, pancakes, brownies) or to readily available foods (applesauce, pudding, yogurt) was conducted among 30 children (median age = 13 years) reporting to a clinic for routine follow-up, sick visits, or transfusion for SCD to determine acceptability. A food preference rank scale (1-7) was used to rank products based on taste, sight, smell, and texture. An average score for each product was computed. Children were also asked to rank their top three products. The top-ranked products were flaxseed baked in brownies and cookies and ground flaxseed added to yogurt. More than 80% of participants indicated willingness to be contacted for a follow-up study in which a flaxseed-supplemented diet would be evaluated for mitigation of SCD-associated pain. In conclusion, flaxseed-enriched products are palatable and acceptable in children with SCD.

Clinical trial considerations in sickle cell disease: patient-reported outcomes, data elements, and the stakeholder engagement framework

Patients with sickle cell disease (SCD) have significant impairment in their quality of life across the life span as a consequence of serious disease burden with several SCD-related complications. A number of disease-modifying therapies are currently available, yet long-term clinical benefits in real-world settings remain unclear. Over the past few years, a number of important initiatives have been launched to optimize clinical trials in SCD in different ways, including: (1) established panels through a partnership between the American Society of Hematology (ASH) and the US Food and Drug Administration; (2) the ASH Research Collaborative SCD Clinical Trials Network; (3) the PhenX Toolkit (consensus measures for Phenotypes and eXposures) in SCD; and (4) the Cure Sickle Cell Initiative, led by the National Heart, Lung, and Blood Institute. Electronic patient-reported outcomes assessment is highly recommended, and patient-reported outcomes (PROs) should be evaluated in all SCD trials and reported using Standard Protocol Items Recommendations for Interventional Trials guidelines. Patient-centered outcomes research (PCOR) approaches and meaningful stakeholder engagement throughout the process have the potential to optimize the execution and success of clinical trials in SCD with considerable financial value. This article reviews several clinical trial considerations in SCD related to study design and outcomes assessment as informed by recent initiatives as well as patient-centered research approaches and stakeholder engagement. A proposed hematology stakeholder-engagement framework for clinical trials is also discussed.

Accelerated approval of Oxbryta® (voxelotor): A case study on novel endpoint selection in sickle cell disease

Sickle cell disease (SCD) is an inherited disease characterized by hemolysis, anemia, and vaso-occlusion leading to substantial morbidity and mortality. Development of prior pharmacologic therapies exclusively utilized vaso-occlusive crisis (VOC) as a clinical efficacy endpoint; however, this focus on VOC did not capture the full extent of disease symptomatology and complications and slowed the development of new therapies. Voxelotor, a hemoglobin S polymerization inhibitor, was recently approved in the United States for the treatment of SCD in adults and adolescents 12 years of age and older through an accelerated approval pathway. The rapid approval and availability of voxelotor was facilitated in a collaborative effort with the US Food and Drug Administration (FDA), using hemoglobin, a biologic surrogate endpoint, as reasonably likely to predict clinical benefit. Use of this new endpoint was supported by FDA-led multistakeholder discussions with physician and patient communities to identify unmet needs and potential clinical trial endpoints, as well as by a company-sponsored analysis of external patient-level data to demonstrate a correlation between hemoglobin change and stroke risk. A two-part phase 3 study was used to allow for rank ordering of key secondary endpoints based on a planned interim analysis. Continued open communication with the FDA was essential to gain agreement on hemoglobin as a novel endpoint and to address the unmet and urgent need of new therapies for SCD.

Applicability and added value of novel methods to improve drug development in rare diseases

BACKGROUND

The ASTERIX project developed a number of novel methods suited to study small populations. The objective of this exercise was to evaluate the applicability and added value of novel methods to improve drug development in small populations, using real world drug development programmes as reported in European Public Assessment Reports.

METHODS

The applicability and added value of thirteen novel methods developed within ASTERIX were evaluated using data from 26 European Public Assessment Reports (EPARs) for orphan medicinal products, representative of rare medical conditions as predefined through six clusters. The novel methods included were 'innovative trial designs' (six methods), 'level of evidence' (one method), 'study endpoints and statistical analysis' (four methods), and 'meta-analysis' (two methods) and they were selected from the methods developed within ASTERIX based on their novelty; methods that discussed already available and applied strategies were not included for the purpose of this validation exercise. Pre-requisites for application in a study were systematized for each method, and for each main study in the selected EPARs it was assessed if all pre-requisites were met. This direct applicability using the actual study design was firstly assessed. Secondary, applicability and added value were explored allowing changes to study objectives and design, but without deviating from the context of the drug development plan. We evaluated whether differences in applicability and added value could be observed between the six predefined condition clusters.

RESULTS AND DISCUSSION

Direct applicability of novel methods appeared to be limited to specific selected cases. The applicability and added value of novel methods increased substantially when changes to the study setting within the context of drug development were allowed. In this setting, novel methods for extrapolation, sample size re-assessment, multi-armed trials, optimal sequential design for small sample sizes, Bayesian sample size re-estimation, dynamic borrowing through power priors and fall-back tests for co-primary endpoints showed most promise - applicable in more than 40% of evaluated EPARs in all clusters. Most of the novel methods were applicable to conditions in the cluster of chronic and progressive conditions, involving multiple systems/organs. Relatively fewer methods were applicable to acute conditions with single episodes. For the chronic clusters, Goal Attainment Scaling was found to be particularly applicable as opposed to other (non-chronic) clusters.

CONCLUSION

Novel methods as developed in ASTERIX can improve drug development programs. Achieving optimal added value of these novel methods often requires consideration of the entire drug development program, rather than reconsideration of methods for a specific trial. The novel methods tested were mostly applicable in chronic conditions, and acute conditions with recurrent episodes.

Sickle cell disease

Sickle cell disease (SCD) is a group of inherited disorders caused by mutations in HBB, which encodes haemoglobin subunit β. The incidence is estimated to be between 300,000 and 400,000 neonates globally each year, the majority in sub-Saharan Africa. Haemoglobin molecules that include mutant sickle β-globin subunits can polymerize; erythrocytes that contain mostly haemoglobin polymers assume a sickled form and are prone to haemolysis. Other pathophysiological mechanisms that contribute to the SCD phenotype are vaso-occlusion and activation of the immune system. SCD is characterized by a remarkable phenotypic complexity. Common acute complications are acute pain events, acute chest syndrome and stroke; chronic complications (including chronic kidney disease) can damage all organs. Hydroxycarbamide, blood transfusions and haematopoietic stem cell transplantation can reduce the severity of the disease. Early diagnosis is crucial to improve survival, and universal newborn screening programmes have been implemented in some countries but are challenging in low-income, high-burden settings.

Clinical trial conduct in special populations and developing regions: An overview of the DOVE study in pediatric patients with sickle cell disease

Clinical trials conducted in unique patient populations or individuals with rare diseases are typically hampered by limitations in availability of qualified patients, requiring sponsors to broaden their global outreach to achieve enrollment. Engaging clinical study centers in developing regions may offer access to a substantially larger patient pool. However, they provide a unique set of challenges based on local cultures and requirements. The DOVE study (Determining effects Of platelet inhibition on Vaso-occlusive Events) was a clinical trial of prasugrel hydrochloride (prasugrel) in pediatric patients (aged 2 to <18years) with sickle cell anemia. The study was conducted at centers located in both well-developed and developing regions, enrolling 341 children. Study planning and execution required careful consideration of cultural requirements in each region and implementation of additional trial initiation and execution processes to address those needs. Innovative strategies were employed to ensure global consistency and quality in study execution. Significant regional- and country-specific differences were observed in site activation and enrollment. Although site activation processes were more complex and slower in developing countries, enrollment rates were much higher, which helped mitigate the site activation delays and allowed significant contribution to complete study enrollment. Data quality and patient retention in developing countries were equivalent to those observed in more developed countries, further supporting the ability to successfully conduct high-quality global registration trials in those countries. This report provides an overview of the experiences in site identification, site qualification, enrollment, patient retention, and data quality assurance in the DOVE study.

Acute kidney injury during a pediatric sickle cell vaso-occlusive pain crisis

BACKGROUND

Patients who develop sickle cell disease (SCD) nephropathy are at a high risk for mortality. The pathophysiology of vaso-occlusive pain crisis may contribute to acute kidney injury (AKI). Non-steroidal anti-inflammatory drugs, known inducers of AKI, are used to treat pain crises. Multiple gaps exist in the knowledge about the impact of AKI in SCD.

METHODS

We conducted a 2-year retrospective review of AKI events in patients admitted for vaso-occlusive crisis. AKI was defined by an increase of ≥0.3 mg/dL or 50% in serum creatinine from baseline. Laboratory values and ketorolac administration by days and dose (mg/kg) were identified from hospital records. A generalized mixed effects model for binary outcomes evaluated AKI based on laboratory variables and ketorolac administration. A generalized mixed Poisson effects model analyzed the association of AKI with hospital length of stay.

RESULTS

Thirty-three out of 197 admissions for vaso-occlusive pain crisis (17%) were associated with AKI. Fifty-two percent of the cases presented to the Emergency Room (ER) with AKI. Every one unit decrease in hemoglobin from baseline to admission increased the risk of AKI by 49%. Among patients who received ketorolac for pain, both total days and doses of ketorolac were associated with AKI. Finally, patients with pain and AKI required longer periods of hospitalization than patients without AKI.

CONCLUSION

Acute kidney injury during sickle cell pain crisis is common and may be an important modifiable risk factor for developing chronic kidney disease (CKD). Further studies are needed to determine the impact of nephrotoxic medications on progressive SCD nephropathy.

A systematic review of the processes used to link clinical trial registrations to their published results

BACKGROUND

Studies measuring the completeness and consistency of trial registration and reporting rely on linking registries with bibliographic databases. In this systematic review, we quantified the processes used to identify these links.

METHODS

PubMed and Embase databases were searched from inception to May 2016 for studies linking trial registries with bibliographic databases. The processes used to establish these links were categorised as automatic when the registration identifier was available in the bibliographic database or publication, or manual when linkage required inference or contacting of trial investigators. The number of links identified by each process was extracted where available. Linear regression was used to determine whether the proportions of links available via automatic processes had increased over time.

RESULTS

In 43 studies that examined cohorts of registry entries, 24 used automatic and manual processes to find articles; 3 only automatic; and 11 only manual (5 did not specify). Twelve studies reported results for both manual and automatic processes and showed that a median of 23% (range from 13 to 42%) included automatic links to articles, while 17% (range from 5 to 42%) of registry entries required manual processes to find articles. There was no evidence that the proportion of registry entries with automatic links had increased (R ² = 0.02, p = 0.36). In 39 studies that examined cohorts of articles, 21 used automatic and manual processes; 9 only automatic; and 2 only manual (7 did not specify). Sixteen studies reported numbers for automatic and manual processes and indicated that a median of 49% (range from 8 to 97%) of articles had automatic links to registry entries, and 10% (range from 0 to 28%) required manual processes to find registry entries. There was no evidence that the proportion of articles with automatic links to registry entries had increased (R ² = 0.01, p = 0.73).

CONCLUSIONS

The linkage of trial registries to their corresponding publications continues to require extensive manual processes. We did not find that the use of automatic linkage has increased over time. Further investigation is needed to inform approaches that will ensure publications are properly linked to trial registrations, thus enabling efficient monitoring of trial reporting.

New insights into sickle cell disease: mechanisms and investigational therapies

PURPOSE OF REVIEW

Sickle cell disease (SCD) afflicts millions worldwide. The simplicity of its single nucleotide mutation belies the biological and psychosocial complexity of the disease. Despite only a single approved drug specifically for the treatment of SCD, new findings reviewed from 2015 provide the direction forward.

RECENT FINDINGS

The last year has provided a wealth of support for mechanisms affecting the red cell, hemolysis and vasculopathy, the innate immune system activation, blood cell and endothelial adhesiveness, central sensitization to pain, and chronic brain injury. The evidence supporting expanded use of hydroxyurea continues to mount. Many promising therapies are reaching clinical trial, including curative therapies, with more on the horizon.

SUMMARY

Evidence is compelling that the use of hydroxyurea must be expanded by clinicians to gain the full pleiotropic benefits of this approved drug. Clinicians must become aware that severe acute and chronic pain has a biological and neurologic basis, and the understanding of this basis is growing. Researchers are testing investigational therapies at an unprecedented pace in SCD, and partnership between patients, researchers, and the private sector provides the most rapid and productive way forward.

Using re-randomization to increase the recruitment rate in clinical trials - an assessment of three clinical areas

Background

Patient recruitment in clinical trials is often challenging, and as a result, many trials are stopped early due to insufficient recruitment. The re-randomization design allows patients to be re-enrolled and re-randomized for each new treatment episode that they experience. Because it allows multiple enrollments for each patient, this design has been proposed as a way to increase the recruitment rate in clinical trials. However, it is unknown to what extent recruitment could be increased in practice.

Methods

We modelled the expected recruitment rate for parallel-group and re-randomization trials in different settings based on estimates from real trials and datasets. We considered three clinical areas: in vitro fertilization, severe asthma exacerbations, and acute sickle cell pain crises. We compared the two designs in terms of the expected time to complete recruitment, and the sample size recruited over a fixed recruitment period.

Results

Across the different scenarios we considered, we estimated that re-randomization could reduce the expected time to complete recruitment by between 4 and 22 months (relative reductions of 19% and 45%), or increase the sample size recruited over a fixed recruitment period by between 29% and 171%. Re-randomization can increase recruitment most for trials with a short follow-up period, a long trial recruitment duration, and patients with high rates of treatment episodes.

Conclusions

Re-randomization has the potential to increase the recruitment rate in certain settings, and could lead to quicker and more efficient trials in these scenarios.

Trends in Research with U.S. Military Service Member Participants: A Population-Specific ClinicalTrials.gov Review

BACKGROUND

ClinicalTrials.gov reviews have evaluated research trends for specific conditions and age groups but not for specific populations of research participants. No ClinicalTrials.gov reviews have evaluated research with military service member participants.

PURPOSE

Study objectives were (a) to use ClinicalTrials.gov to identify trends in biomedical research from 2005 to 2014 in which U.S. military service members actively participated as research participants and (b) to describe a search strategy for adaptation in future ClinicalTrials.gov reviews of specific participant populations.

METHODS

A systematic review of ClinicalTrials.gov was performed to identify studies that included U.S. service members as participants, either exclusively or with other groups of participants.

RESULTS

U.S. service members were identified as participants in 512 studies. Service members participated together with other groups in 392 studies, while 120 studies included only service members. The top five conditions of interest were post-traumatic stress disorder, traumatic brain injury, amputations, burns, and ocular injuries/disorders. The number of studies started each year peaked in 2011 and declined from 2012 to 2014. Twenty-five percent of studies exclusive to service members aimed to enroll 500 or more participants. Research exclusive to Guard and Reserve service members during this period was limited.

CONCLUSIONS

U.S. military service members participate in biomedical research. To address the health needs of U.S. service members, it is important to ensure there is not a prolonged decline in research among this population. The search strategy may be adapted to ClinicalTrials.gov reviews of specific participant populations for which straightforward searches are not possible.

Mistrust of Pediatric Sickle Cell Disease Clinical Trials Research

INTRODUCTION

Sickle cell disease (SCD) research is hampered by disparities in participation due in part to mistrust of research among racial/ethnic minorities. Beyond the historic context of research misconduct, little is known about the associations of social ecologic factors with mistrust and of mistrust with SCD clinical trials enrollment. This study evaluated proximal (age, gender, disease severity, perceived stress, SES) and distal (religious beliefs, social support, instrumental support) factors related to mistrust of research among caregivers of children with SCD and adolescents and young adults (AYAs) with SCD.

METHODS

Over an 18-month period (2009-2010), participants completed questionnaires of perceived barriers and benefits to clinical trials enrollment, perceived stress, and self-reported demographic and disease-related information. Analyses (January-June 2015) used multivariable linear regressions to evaluate predictors of mistrust.

RESULTS

Data were analyzed for 154 caregivers (mean age, 38.75 years; SD=9.56 years; 90.30% female) and 88 AYAs (mean age, 24.76 years; SD=7.25 years; 46.40% female). Among caregivers (full model, R(2)=0.14, p≤0.001), greater mistrust was explained by higher perceived stress (β=0.04, p=0.052); religious beliefs (β=0.61, p≤0.001); and greater instrumental support (β=0.07, p=0.044). Among AYAs (full model, R(2)=0.18, p≤0.001), higher mistrust was explained by being male (β=-0.56, p≤0.001) and lower instrumental support (β=-0.11, p=0.016). Mistrust was significantly greater among caregivers that reported no prior involvement in medical research (p=0.003).

CONCLUSIONS

By understanding the complexity through which social ecologic factors contribute to mistrust, researchers may create targeted strategies to address mistrust and increase engagement in SCD research for caregivers and AYAs.

Hydroxyurea decreases hospitalizations in pediatric patients with Hb SC and Hb SB+ thalassemia

PURPOSE

Patients with hemoglobin SC (Hb SC) and hemoglobin SB+ (Hb SB+) thalassemia suffer from frequent hospitalizations yet strong evidence of a clinical benefit of hydroxyurea (HU) in this population is lacking. Patients with recurrent hospitalizations for pain crisis are offered HU at our institution based on small cohort data and anecdotal benefit. This study identifies outcomes from a large cohort of patients with Hb SC and SB+ thalassemia who were treated with HU for 2 years.

MATERIALS AND METHODS

A retrospective review was conducted of 32 patients with Hb SC and SB+ thalassemia who were treated with HU. We reviewed the number, and reasons for hospitalization in the 2 years prior to, and 2 years post-HU treatment as well as laboratory changes from baseline, over 1 year.

RESULTS

Patients with Hb SC and SB+ thalassemia started on HU for frequent pain, had a significant reduction in hospitalizations over 2 years as compared to the 2 years prior to HU initiation (mean total hospitalizations/year: pre-HU: 1.6 vs post-HU 0.4 hospitalizations, P<0.001; mean pain hospitalizations/year: pre-HU 1.5 vs post-HU 0.3 hospitalizations, P<0.001). Patients demonstrated hematologic changes including an increase in percent fetal hemoglobin (%HbF) pre-post HU (4.5% to 7.7%, P=0.002), mean corpuscular volume (74 to 86 fL, P<0,0001), and decrease in absolute neutrophil count (5.0 to 3.2×10(9)/L, P=0.007). Patients with higher doses of HU demonstrated the greatest reduction in hospitalizations but this was unrelated to absolute neutrophil count.

CONCLUSION

This cohort of patients with Hb SC and SB+ thalassemia provides additional support for using HU in patients with recurrent hospitalizations for pain. A large randomized multicenter trial of HU to reduce pain admissions should be conducted to confirm these data and provide much needed evidence based recommendations for this population.