Trial-level factors affecting accrual and completion of oncology clinical trials: A systematic review

Analyzing determinants of premature trial discontinuation in leukemia clinical trials

Clinical trials are crucial for improving patient outcomes. Although a significant number of trials are discontinued prematurely, our understanding of factors influencing early termination is limited. We conducted a comprehensive search of ClinicalTrials.gov to identify leukemia trials from 2000 to 2020, followed by data abstraction performed by two independent reviewers. Among 3522 leukemia clinical trials identified, 28.4% were terminated prematurely. Slow accrual was the leading cause of termination 38.2%. The termination rate increased significantly from 17.0% between 2000 and 2005 to 30.9% between 2010 and 2015 (p < .001). Large trials had a lower termination rate than small trials (p < .001). Academic-sponsored trials had the highest termination rates compared to other sponsors' trials (p < .001). Early-phase trials showed higher termination rates compared to late-phase (p < .001). Other significant factors included a sequential assignment, single-center, and non-randomized trials (p < .001). Much of leukemia trials are terminated prematurely, with slow accrual being the most common reason for early termination.

A student-community partnership to enhance cancer research training

BACKGROUND

Despite the importance of community involvement in research, little formal training in community outreach and engagement (COE) is offered to cancer research trainees. A collaboration between the Office of COE and the Office of Cancer Research Training and Education Coordination (CRTEC) at the Sidney Kimmel Comprehensive Cancer Center at Jefferson led to the COE-CRTEC Trainee Working Group, a unique program in which trainees in cancer research each created a novel COE initiative.

METHODS

Four cancer research trainees were selected to serve as COE Program Liaisons (CPLs), each aligned with one of the four cancer center research programs. Each CPL developed, implemented, and evaluated a project that enhanced the bidirectional relationship between their research and the community. Trainees were provided a modest budget, support from the Office of COE, and a requirement to complete the project within one academic year.

RESULTS

Projects included a cancer education seminar for older adults at a senior center, a prostate cancer education and screening event at a predominantly African American church, a video demonstrating a day in the life of a skin cancer researcher, and a podcast that featured SKCCC investigators answering research questions from community members.

CONCLUSION

Students who would not typically be exposed to COE training gained experience developing, implementing, and evaluating community-based initiatives. Projects were diverse in topic and approach, reflecting the diversity of the trainees and the community. Allowing trainees, those who are the next generation of cancer researchers, to design community-based research may lead to more patient-centered research in the future.

Consideration of factors of low accrual and methods for setting appropriate accrual periods: Japan Clinical Oncology Group study

BACKGROUND

Poor patient accrual can delay reporting of clinical trials and, consequently, the development of new treatments. For reducing the risk of additional resource requirements, a method for setting planned accrual periods with minimal deviation from the actual accrual periods is desirable. Risk factors for poor patient accrual and the appropriate method of estimating the required accrual period for timely completion of clinical trials were evaluated using the data of trials conducted by the Japan Clinical Oncology Group.

METHODS

The study included 199 trials that started patient accrual between January 1, 1990, and June 30, 2021. The explanatory variables included factors that could be evaluated prior to trial commencement. We also evaluated whether the estimation methods for accrual pace could lead to completion within the planned accrual period.

RESULTS

Approximately 23.6% of trials were completed within the planned accrual period. The risk factors for trial extension included planned accrual periods > 3 years (reference group: ≤ 3 years, odds ratio [OR] 0.37, 95% confidence interval [CI]: 0.15-0.92, P = 0.033) and stratified trial design (reference group: nonrandomized phase II trials, nonrandomized phase III trial [OR: 3.28, 95% CI: 0.99-10.9, P = 0.051], randomized phase II trial [OR: 3.91, 95% CI: 0.75-20.30, P = 0.105], and randomized phase III trial [OR: 9.29, 95% CI: 3.39-25.40, P < 0.001]). The method of estimating the accrual pace based on past clinical trials facilitated timely completion of the trial (OR: 3.51; 95% CI: 1.73-7.10, P < 0.001), unlike the estimation method based on survey evaluation of the accrual pace for participating institutions (OR: 1.12, 95% CI: 0.56-2.26, P = 0.751). Furthermore, the discrepancy between planned and actual accrual periods was minimal when using the methods of considering the accrual pace of past clinical trials.

CONCLUSIONS

Considering the accrual pace of past clinical trials is useful for estimating the required accrual period if data from past trials are available. When conducting a survey, it is necessary to be cautious of overestimating the cases at each facility.

The Trial Enrollment Diversity Dashboard for Acute Leukemia Clinical Research: Intervention Development and Cohort Analysis

PURPOSE

Participation in acute leukemia clinical trials is inequitable across multiple sociodemographic categories. Tools that provide researchers with performance feedback on the representativeness of the patients they enroll are limited. We aimed to develop an electronic health record (EHR)-based dashboard to provide such feedback and to describe any enrollment inequities uncovered.

METHODS

We created a visual dashboard linking leukemia clinical trial registration and EHR data at the Dana-Farber Cancer Institute. Accuracy of a patient inclusion and assignment algorithm was tested with a target area under the receiver-operator curve (AUROC) of >0.90 against manual review. Demographic metric identification, visualization construction, and dashboard refinement were performed through stakeholder cognitive testing. Analysis of a recent 5-year cohort generated by the final algorithm assessed bivariate associations between enrollment and demographic metrics. Multivariable logistic regression included significant bivariate results.

RESULTS

The final algorithm assignment AUROC was 0.98. Metrics were identified and visualizations successfully constructed. Fourteen individuals participated in testing and identified areas for revision: category mergers, denominator filters, and data delivery preferences. In the initial cohort of 1,315 patients, 1,020 (77.6%) had enrolled in any study protocol: 553 (42.1%) in a treatment trial and 936 (71.2%) in a biobanking study. In a multivariable model, older age (odds ratio [OR], 0.83 [95% CI, 0.73 to 0.94]) and Non-Hispanic Black race-ethnicity (OR, 0.38 [95% CI, 0.18 to 0.82]) were associated with lower enrollment, and English primary language with higher enrollment (OR, 2.50 [95% CI, 1.30 to 4.79]).

CONCLUSION

We developed a research participation equity performance feedback dashboard for clinical researchers, and we identified actionable inequities. Next steps include feasibility and efficacy testing as well as implementation.

Patient Enrollment per Month (Accrual) in Clinical Trials Leading to the FDA Approval of New Cancer Drugs

BACKGROUND

Insufficient patient enrollment per month (=accrual) is the leading cause of cancer trial termination.

OBJECTIVE

To identify and quantify factors associated with patient accrual in trials leading to the US Food and Drug Administration (FDA) approval of new cancer drugs.

DATA

All anti-cancer drugs with FDA approval were identified in the Drugs@FDA database (2000-2022). Data on drug indication's background-, treatment-, disease-, and trial-related factors were collected from FDA labels, clinicaltrials.gov, and the Global Burden of Disease study. The association between patient accrual and collected variables was assessed in Poisson regression models reporting adjusted rate ratios (aRR).

RESULTS

We identified 170 drugs with approval in 455 cancer indications on the basis of 292 randomized and 163 single-arm trials. Among randomized trials, median enrollment per month was 38 patients (interquartile range [IQR]: 26-54) for non-orphan, 21 (IQR: 15-38, aRR 0.88, p = 0.361) for common orphan, 20 (IQR: 10-35, aRR 0.73, p <0.001) for rare orphan, and 8 (IQR 6-12, aRR 0.30, p < 0.001) for ultra-rare orphan indications. Patient enrollment was positively associated with disease burden [aRR: 1.0003 per disability-adjusted life year (DALY), p < 0.001), trial sites (aRR: 1.001 per site, p < 0.001), participating countries (aRR: 1.02 per country, p < 0.001), and phase 3 vs. 1/2 trials (aRR: 1.64, p = 0.037). Enrollment was negatively associated with advanced-line vs. first-line treatments (aRR: 0.81, p = 0.010) and monotherapy vs. combination treatments (aRR: 0.80, p = 0.007). Patient enrollment per month was similar between indications with and without a biomarker (median: 27 vs. 32, aRR 0.80, p = 0.117). Patient enrollment per month was substantially lower in government-sponsored than industry-sponsored trials (median: 14 vs. 32, aRR 0.80, p = 0.209). Enrollment was not associated with randomization ratios, crossover, and study blinding.

CONCLUSIONS

Disease incidence and disease burden alongside the number of study sites and participating countries are the main drivers of patient enrollment in clinical trials. For rare disease trials, greater financial incentives could help expedite patient enrollment. Novel trial design features, including skewed randomization, crossover, or open-label masking, did not entice patient enrollment.

Radiation Therapy Quality Assurance Analysis of Alliance A021501: Preoperative mFOLFIRINOX or mFOLFIRINOX Plus Hypofractionated Radiation Therapy for Borderline Resectable Adenocarcinoma of the Pancreas

PURPOSE

Alliance A021501 is the first randomized trial to evaluate stereotactic body radiation therapy (SBRT) for borderline resectable pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant chemotherapy. In this post hoc study, we reviewed the quality of radiation therapy (RT) delivered.

METHODS AND MATERIALS

SBRT (6.6 Gy × 5) was intended but hypofractionated RT (5 Gy × 5) was permitted if SBRT specifications could not be met. Institutional credentialing through the National Cancer Institute-funded Imaging and Radiation Oncology Core (IROC) was required. Rigorous RT quality assurance (RT QA) was mandated, including pretreatment review by a radiation oncologist. Revisions were required for unacceptable deviations. Additionally, we performed a post hoc RT QA analysis in which contours and plans were reviewed by 3 radiation oncologists and assigned a score (1, 2, or 3) based on adequacy. A score of 1 indicated no deviation, 2 indicated minor deviation, and 3 indicated a major deviation that could be clinically significant. Clinical outcomes were compared by treatment modality and by case score.

RESULTS

Forty patients were registered to receive RT (1 planned but not treated) at 27 centers (18 academic and 9 community). Twenty-three centers were appropriately credentialed for moving lung/liver targets and 4 for static head and neck only. Thirty-two of 39 patients (82.1%) were treated with SBRT and 7 (17.9%) with hypofractionated RT. Five cases (13%) required revision before treatment. On post hoc review, 23 patients (59.0%) were noted to have suboptimal contours or plan coverage, 12 (30.8%) were scored a 2, and 11 (28.2%) were scored a 3. There were no apparent differences in failure patterns or surgical outcomes based on treatment technique or post hoc case score. Details related to on-treatment imaging were not recorded.

CONCLUSIONS

Despite rigorous QA, we encountered variability in simulation, contouring, plan coverage, and dose on trial. Although clinical outcomes did not appear to have been affected, findings from this analysis serve to inform subsequent PDAC SBRT trial designs and QA requirements.

Phase II study of vemurafenib in children and young adults with tumors harboring BRAF V600 mutations: NCI-COG pediatric MATCH trial (APEC1621) Arm G

BACKGROUND

This is a phase II subprotocol of the NCI-COG Pediatric MATCH study evaluating vemurafenib, a selective oral inhibitor of BRAF V600 mutated kinase, in patients with relapsed or refractory solid tumors harboring BRAF V600 mutations.

METHODS

Patients received vemurafenib at 550 mg/m2 (maximum 960 mg/dose) orally twice daily for 28-day cycles until progression or intolerable toxicity. The primary aim was to determine the objective response rate and secondary objectives included estimating progression-free survival and assessing the tolerability of vemurafenib.

RESULTS

Twenty-two patients matched to the subprotocol and 4 patients (18%) enrolled. Primary reasons for non-enrollment were ineligibility due to exclusions of low-grade glioma (n = 7) and prior BRAF inhibitor therapy (n = 7). Enrolled diagnoses were one each of histiocytosis, ameloblastoma, Ewing sarcoma, and high-grade glioma, all with BRAF V600E mutations. Treatment was overall tolerable with mostly expected grade 1/2 adverse events (AE). Grade 3 or 4 AE on treatment were acute kidney injury, hyperglycemia, and maculopapular rash. One patient came off therapy due to AE. One patient (glioma) had an objective partial response and remained on protocol therapy for 15 cycles.

CONCLUSION

There was a low accrual rate on this MATCH subprotocol, with only 18% of those who matched with BRAFV600 mutations enrolling, resulting in early termination, and limiting study results (ClinicalTrials.gov Identifier: NCT03220035).

Special FDA designations for drug development: orphan, fast track, accelerated approval, priority review, and breakthrough therapy

BACKGROUND

Over the past decades, US Congress enabled the US Food and Drug Administration (FDA) to facilitate and expedite drug development for serious conditions filling unmet medical needs with five special designations and review pathways: orphan, fast track, accelerated approval, priority review, and breakthrough therapy.

OBJECTIVES

This study reviews the FDA's five special designations for drug development regarding their safety, efficacy/clinical benefit, clinical trials, innovation, economic incentives, development timelines, and price.

METHODS

We conducted a keyword search to identify studies analyzing the impact of the FDA's special designations (orphan, fast track, accelerated approval, priority review, and breakthrough therapy) on the safety, efficacy/clinical benefit, trials, innovativeness, economic incentives, development times, and pricing of new drugs. Results were summarized in a narrative overview.

RESULTS

Expedited approval reduces new drugs' time to market. However, faster drug development and regulatory review are associated with more unrecognized adverse events and post-marketing safety revisions. Clinical trials supporting special FDA approvals frequently use small, non-randomized, open-label designs. Required post-approval trials to monitor unknown adverse events are often delayed or not even initiated. Evidence suggests that drugs approved under special review pathways, marketed as "breakthroughs", are more innovative and deliver a higher clinical benefit than those receiving standard FDA approval. Special designations are an economically viable strategy for investors and pharmaceutical companies to develop drugs for rare diseases with unmet medical needs, due to financial incentives, expedited development timelines, higher clinical trial success rates, alongside greater prices. Nonetheless, patients, physicians, and insurers are concerned about spending money on drugs without a proven benefit or even on drugs that turn out to be ineffective. While European countries established performance- and financial-based managed entry agreements to account for this uncertainty in clinical trial evidence and cost-effectiveness, the pricing and reimbursement of these drugs remain largely unregulated in the US.

CONCLUSION

Special FDA designations shorten clinical development and FDA approval times for new drugs treating rare and severe diseases with unmet medical needs. Special-designated drugs offer a greater clinical benefit to patients. However, physicians, patients, and insurers must be aware that special-designated drugs are often approved based on non-robust trials, associated with more unrecognized side effects, and sold for higher prices.

Ethical Considerations in Decentralized Clinical Trials

As a consequence of the COVID-19 pandemic, the number of decentralized clinical trials, trials conducted in whole or in part at locations other than traditional clinical trial sites, significantly increased. While these trials have the potential advantage of access, participant centricity, convenience, lower costs, and efficiency, they also raise a number of important ethical and practical concerns. Here we focus on a number of those concerns, including participant safety, privacy and confidentiality, remote consent, digital access and proficiency, and trial oversight. Awareness of these ethical complexities will help foster the development of processes and cooperative solutions to promote safe, ethical trials going forward, optimized to decrease burden and increase access for all participants.

Combined Results of Two Cross-Sectional Surveys on the Participation in Clinical Trials and the e-Consent Procedure in the Landscape of Haematology

Despite the motivation of oncology patients to take part in clinical trials, only a minority of them are enrolled in clinical trials. Implementation of new practical procedures can become a barrier that withholds patients from participating in clinical trials. Treating physicians are crucial in augmenting trial accrual. The drivers that promote physicians to allocate patients for clinical trials need further assessment. We conducted two separate cross-sectional surveys, addressing patients with a haematological disease in one survey and haematologists in another survey. The patient survey was filled out by 420 patients. Significant relationships between the willingness to participate in a trial and trial knowledge (p < 0.001) and between doctor-patient relationship and participation willingness (p = 0.007) were noted. Patients above 60 years were less willing to use an electronic consent procedure vs. patients younger than 60 (p < 0.001). The physician questionnaire was completed by 42 participants of whom most (83%) were active in and (94%) motivated for clinical trials. Apart from the patient benefit and scientific interest, prestige was an equal motivator closely followed by financial remunerations. First goal was not to harm the patient. Our study confirms the high willingness of patients for trial participation and the need to rethink the structure of trial organisation. The e-consent procedure is not the method preferred by most patients above 60 years old.

Can we predict trial failure among older adult-specific clinical trials using trial-level factors?

INTRODUCTION

Conducting older adult-specific clinical trials can help overcome the lack of clinical evidence for older adults due to their underrepresentation in clinical trials. Understanding factors contributing to the successful completion of such trials can help trial sponsors and researchers prioritize studies and optimize study design. We aimed to develop a model that predicts trial failure among older adult-specific cancer clinical trials using trial-level factors.

MATERIALS AND METHODS

We identified phase 2-4 interventional cancer clinical trials that ended between 2008 and 2019 and had the minimum age limit of 60 years old or older using Aggregate Analysis of ClinicalTrials.gov data. We defined trial failure as closed early for reasons other than interim results or toxicity or completed with a sample of <85% of the targeted size. Candidate trial-level predictors were identified from a literature review. We evaluated eight types of machine learning algorithms to find the best model. Model fitting and testing were performed using 5-fold nested cross-validation. We evaluated the model performance using the area under receiver operating characteristic curve (AUROC).

RESULTS

Of 209 older adult-specific clinical trials, 87 were failed trials per the definition of trial failure. The model with the highest AUROC in the validation set was the least absolute shrinkage and selection operator (AUROC in the test set = 0.70; 95% confidence interval [CI]: 0.53, 0.86). Trial-level factors included in the best model were the study sponsor, the number of participating centers, the number of modalities, the level of restriction on performance score, study location, the number of arms, life expectancy restriction, and the number of target size. Among these factors, the number of centers (odds ratio [OR] = 0.83, 95% CI: 0.71, 0.94), study being in non-US only vs. US only (OR = 0.32, 95% CI: 0.12, 0.82), and life expectancy restriction (OR = 2.17, 95% CI: 1.04, 4.73) were significantly associated with the trial failure.

DISCUSSION

We identified trial-level factors predictive of trial failure among older adult-specific clinical trials and developed a prediction model that can help estimate the risk of failure before a study is conducted. The study findings could aid in the design and prioritization of future older adult-specific clinical trials.

Implementation and Clinical Adoption of Precision Oncology Workflows Across a Healthcare Network

BACKGROUND

Precision oncology relies on molecular diagnostics, and the value-proposition of modern healthcare networks promises a higher standard of care across partner sites. We present the results of a clinical pilot to standardize precision oncology workflows.

METHODS

Workflows are defined as the development, roll-out, and updating of disease-specific molecular order sets. We tracked the timeline, composition, and effort of consensus meetings to define the combination of molecular tests. To assess clinical impact, we examined order set adoption over a two-year period (before and after roll-out) across all gastrointestinal and hepatopancreatobiliary (GI) malignancies, and by provider location within the network.

RESULTS

Development of 12 disease center-specific order sets took ~9 months, and the average number of tests per indication changed from 2.9 to 2.8 (P = .74). After roll-out, we identified significant increases in requests for GI patients (17%; P < .001), compliance with testing recommendations (9%; P < .001), and the fraction of "abnormal" results (6%; P < .001). Of 1088 GI patients, only 3 received targeted agents based on findings derived from non-recommended orders (1 before and 2 after roll-out); indicating that our practice did not negatively affect patient treatments. Preliminary analysis showed 99% compliance by providers in network sites, confirming the adoption of the order sets across the network.

CONCLUSION

Our study details the effort of establishing precision oncology workflows, the adoption pattern, and the absence of harm from the reduction of non-recommended orders. Establishing a modifiable communication tool for molecular testing is an essential component to optimize patient care via precision oncology.

What drives cancer clinical trial accrual? An empirical analysis of studies leading to FDA authorisation (2015-2020)

OBJECTIVE

To examine factors associated with accrual rate in industry sponsored clinical trials supporting US Food and Drug Administration (FDA) cancer drug approvals from 2015 to 2020.

DESIGN, SETTING AND PARTICIPANTS

Retrospective cross-sectional study included 194 pivotal trials supporting cancer drug approvals by the US FDA from 2015 to 2020.

INTERVENTIONS

Clinical trials were analysed for the type of blinding, primary endpoint, whether crossover was specified in the publication, study phase, line of therapy, response rate, investigational sites, manufacturer and randomisation ratio.

MAIN OUTCOME MEASURES

The main outcome was the rate of accrual, which is the number of patients accrued in the study per open month of enrolment.

RESULTS

The study consisted of 133 randomised (68%) and 61 (32%) non-randomised clinical trials. In randomised studies, we found the accrual rate was higher in trials investigating first and second line drugs (adjusted rate ratios (aRR): 1.55, 95% CI 1.18 to 2.09), phase III trials (aRR: 2.13, 95% CI 1.48 to 2.99), and for studies sponsored by Merck (aRR: 1.47, 95% CI 1.18 to 2.37), adjusting for other covariates. In contrast, the primary endpoint of a study, presence of crossover, single agent response rate, the number of investigational sites, population disease burden and skewed randomisation ratios were not associated with the rate of accrual. In the non-randomised adjusted model, the accrual rate was 2.03 higher (95% CI 1.10 to 3.92) for clinical trials sponsored by manufacturer, specifically Merck. Primary endpoint, crossover, trial phase, response rate, the number of investigational sites, disease burden or line of therapy were not associated with the rate of accrual.

CONCLUSION

In this cross-sectional study, line of therapy, study phase and manufacturer were the only factors associated with accrual rate. These findings suggest many proffered factors for speedy trial accrual are not associated with greater enrolment rates.