Premature termination of clinical trials--lessons learned

Analysis of terminated pulmonary hypertension clinical trials. What are we doing wrong?

Despite significant interest in the diagnosis and treatment of pulmonary hypertension (PH) over the past two decades, there have been no notable advancements in reducing mortality. One contributing factor to this lack of progress is the insufficient number of well-designed and conducted trials. We aimed to evaluate factors associated with termination of PH clinical trials, to serve as a reference when designing future trials. We searched the ClinicalTrials.gov database for PH clinical trials conducted between January 1st 2000 to December 31st 2020. Information collected and analyzed included trial design, status, and publication status. Of the 240 analyzed clinical trials, 81% evaluated therapeutic interventions. Around 30.4% of the trials were terminated, most commonly due to recruitment issues. Terminated trials had a significantly lower number of enrolled patients when compared to trials that were completed (p= .017). Furthermore, there was an overall negative correlation between the year of trial initiation and the total number of enrolled patients (r= -0.18; p= .013). The likelihood of termination decreased by 1.9% for every additional enrolled patient. Ultimately, only 37.5% of the trials have been published. There was a significant positive correlation between number of patients enrolled and the journal's impact factor (r = 0.4, p < 0.05). Pharmaceutical companies sponsored the majority of the trials. The termination rate of PH trials is higher than other conditions. Factors such as recruitment contribute significantly to termination. Further studies are required to evaluate the challenges associated with recruiting this patient population.

Clinical Trials in Gastroesophageal Cancers: An Analysis of the Global Landscape of Interventional Trials From ClinicalTrials.gov

PURPOSE

To describe the global landscape of clinical research into interventions for gastroesophageal cancers (GECs), with examination of trial characteristics, geographic distribution of trial sites, and factors associated with trial termination.

METHODS

We queried ClinicalTrials.gov to identify all completed or terminated phase III interventional studies investigating GECs (esophageal squamous cell carcinoma [ESCC], esophageal adenocarcinoma [EAC], gastroesophageal junctional [GEJ], and gastric adenocarcinoma). Data on all reported trial characteristics were extracted. Pearson's chi-square and Fisher's exact tests were used to compare differences in completed and terminated trials. Multivariate logistic regression evaluated predictors of termination.

RESULTS

A total of 179 trials were identified; of these, 90% were therapeutic. Most included sites in Asia (61%) and Europe (32%); few included sites in Africa (4%). Thirty percent included sites in low- and middle-income countries (LMICs). Most (70%) focused on gastric or GEJ adenocarcinoma, 13% on EAC and ESCC, and 9% on ESCC alone. Sixteen percent (n = 29) of trials terminated prematurely. In multivariate analysis, study site number, location of recruitment sites, and patient population emerged as predictors of termination. Trials recruiting from US-based sites were more likely to terminate (odds ratio [OR], 7.22 [95% CI, 1.59 to 32.69]). Trials conducted exclusively in LMICs were less likely to terminate (OR, 0.04 [95% CI, 0.01 to 0.59] v conducted in high-income countries [HICs] alone). Studies on ESCC were more likely to terminate (OR, 17.74 [95% CI, 1.49 to 210.69]).

CONCLUSION

Although 80% of GECs occur in LMICs, trial activity disproportionately occurs in HICs. Few trials focus on EAC/ESCC despite being highly fatal, highlighting an unmet need. Overall, this study highlights (1) a missed opportunity to recruit patients from high-incidence regions globally; and (2) a pressing need for increasing funding, infrastructure, and support for GEC trials in LMICs.

Early termination of cardiovascular trials as a consequence of poor accrual: analysis of ClinicalTrials.gov 2006-2015

OBJECTIVES

To present a snapshot of experimental cardiovascular research with a focus on geographical and temporal patterns of early termination due to poor accrual.

SETTING

The Aggregate Analysis of ClinicalTrials.gov (AACT) database, reflecting ClinicalTrials.gov as of 27 March 2016.

DESIGN

The AACT database was searched for all cardiovascular clinical trials that started from January 2006 up to December 2015.

RESULTS

Thirteen thousand and seven hundred twenty-nine cardiovascular trials were identified. Of these, 8900 (65%) were classified as closed studies. Globally, 11% of closed trials were terminated. This proportion varied from 9.6% to 14% for trials recruiting from Europe and Americas, respectively, with a slightly decreasing trend (p=0.02) over the study period. The most common reason for trials failing to complete was poor accrual (41%). Intercontinental trials exhibited lower figures of poor accrual as the reason for their early stopping, as compared with trials recruiting in a single continent (28% vs 44%, p=0.002).

CONCLUSIONS

Poor accrual significantly challenges the successful completion of cardiovascular clinical trials. Findings are suggestive of a positive effect of globalisation of cardiovascular clinical research on the achievement of enrolment goals within a reasonable time frame.

Realizing Informed Consent in Times of Controversy: Lessons from the SUPPORT Study

This Essay examines the elegantly simple idea that consent to medical treatment or participation in human research must be "informed" to be valid. It does so by using as a case study the controversial clinical research trial known as the Surfactant, Positive Pressure, and Oxygenation Randomized Trial ("SUPPORT"). The Essay begins by charting, through case law and the adoption of the common rule, the evolution of duties to secure fully informed consent in both research and treatment. The Essay then utilizes the SUPPORT study, which sought to pinpoint the level of saturated oxygen that should be provided to extremely low birth weight infants to demonstrate modern complexities and shortcomings of the duty to secure informed consent. This Essay shows how the duty is measured by foreseeability of risks and benefits in human research and why federal regulators believed the trade-offs in risk and benefits from differing oxygen levels administered in the support study were foreseeable. It then explores the contours of the duty to secure informed consent when applied to researchers who also serve as treating physicians, highlighting how common law duties differ in jurisdictions that apply the professional standard and those that apply the patient-centered material risk standard. This Essay provides new insight into what the law must do to make real the notion that [e]very human being of adult years and sound mind has a right to determine what shall be done with his body."

The impact of health insurance mandates on drug innovation: evidence from the United States

An important health policy issue is the low rate of patient enrollment into clinical trials, which may slow down the process of clinical trials and discourage their supply, leading to delays in innovative life-saving drug treatments reaching the general population. In the US, patients' cost of participating in a clinical trial is considered to be a major barrier to patient enrollment. In order to reduce this barrier, some states in the US have implemented policies requiring health insurers to cover routine care costs for patients enrolled in clinical trials. This paper evaluates empirically how effective these policies were in increasing the supply of clinical trials and speeding up their completion, using data on cancer clinical trials initiated in the US between 2001 and 2007. Our analysis indicates that the policies did not lead to an increased supply in the number of clinical trials conducted in mandate states compared to non-mandate states. However, we find some evidence that once clinical trials are initiated, they are more likely to finish their patient recruitment in a timely manner in mandate states than in non-mandate states. As a result, the overall length to completion was significantly shorter in mandate states than in non-mandate states for cancer clinical trials in certain phases. The findings hint at the possibility that these policies might encourage drug innovation in the long run.