Evaluation of Oncology Trial Results Reporting Over a 10-Year Period

Accrual and statistical power failure in published adjuvant phase III oncology trials: a comprehensive analysis from 2013 to 2023

BACKGROUND

In a competitive landscape with many ongoing adjuvant randomised controlled trials (RCTs), the prevalence of trials that failed to recruit their targeted sample size and were inadequately powered is unclear. The aims of the study are (i) to determine the percentage of trials with accrual and statistical power failure and (ii) to evaluate their potential impact on the drug development process.

MATERIALS AND METHODS

A systematic review was carried out to identify adjuvant phase III oncology RCTs reported between 2013 and 2023 across all solid tumours. No restrictions were applied regarding the type of intervention or journal of publication. The percentage of trials with accrual failure and power failure was estimated as well as their association with the efficacy endpoints. Logistic regression models were used to estimate the odds ratio (OR) and its 95% confidence interval (CI).

RESULTS

A total of 282 RCTs met the inclusion criteria with a median sample size of 661 patients and a median accrual period of 4.3 years. Most of these studies were superiority trials (83.0%). Accrual failure was observed in 22.0% of the studies, finishing recruitment without achieving the targeted sample size. Overall, 39.7% of the studies experienced power failure, having less power than specified in the protocol at the date of the read-out. Among superiority RCTs evaluating intermediate survival endpoints, only 31.1% presented statistically significant results. Trials with power failure were less likely to present statistically significant results (37.9% versus 21.9%, P = 0.04). The association was consistent across all cancer types. In the subset of non-inferiority trials, 35.0% formally demonstrated non-inferiority of the experimental arm.

CONCLUSIONS

Nearly 40% of adjuvant phase III RCTs experienced power failure, and the reduction in power significantly impacted the final study results. There is a need for procedural refinements in the design and implementation of future adjuvant RCTs to mitigate these fallacies.

Poor Result Reporting Rate in Cell Therapy Trials Registered at ClinicalTrials.gov

As research associates in clinical experiments, we have an obligation to disclose clinical methodologies and findings in full transparency in ethics. However, inadequate disclosure in results reporting clinical trials registered on ClinicalTrials.gov has been revealed, with approximately half the trial results not being reported in an applicable manner. Our recent study in clinical trials of regenerative medicine for four kinds of neurological diseases revealed that the rate of result reporting to ClinicalTrials.gov is inadequate for gene and cell therapy (CT) trials. In this path, further curiosity emerged to see what the findings would be if the analysis was conducted for trials in all disease areas, and outcomes if gene therapy (GT) and CT were distinguished in terms. In this study, the scope of analysis was further expanded to include all disease areas, and the drug classification from the AdisInsight database was used for modality classification, with biologic drug trials classified as controls, CT, ex vivo GT, and in vivo GT. To begin, among all interventional clinical trials with registration in the ClinicalTrials.gov registry and with a primary completion between 2010 and 2019, we created a total of 5539 datasets corresponding to trials classified as GT and CT, while biologics (BLG) as controls in the AdisInsight drug classification. The status of reported results of these trials was identified by surveying posting status of ClinicalTrials.gov and publication in journals (PubMed), respectively. Based on the obtained dataset, multivariate analysis was performed on the data on the reporting rate of clinical trial results, aggregated by sponsor, phase, status, and modality (CT, ex vivo GT, in vivo GT, and BLG), respectively. The result shows that CT was identified as an independent factor restraining result reporting ratio in both ClinicalTrials.gov and total disclosures, whereas ex vivo GT as boosting result reporting ratio. Since the result reporting rate of CT results was notably poor, we discussed the causes and solutions in this regard.

Characteristics of immunotherapy trials for nasopharyngeal carcinoma over a 15-year period

Background

Immunotherapy has been a hotspot in nasopharyngeal carcinoma (NPC) in recent years. This study aimed to provide a comprehensive landscape of the characteristics of immunotherapy clinical trials in NPC and to determine whether contemporary studies are of sufficient quality to demonstrate therapeutic value.

Methods

This is a cross-sectional analysis of NPC trials registered on ClinicalTrials.gov in the last 15 years (Jan 1, 2008-Nov 20, 2022). Only interventional trials with a primary purpose of treatment were included in the final analysis. Characteristics of immunotherapy trials were compared with those of other NPC trials. Chronological shifts in NPC immunotherapy trials were also analyzed.

Results

Of the 440 NPC studies selected, 161 (36.6%) were immunotherapy trials and 279 (63.4%) were other NPC trials. NPC immunotherapy trials were more likely than other NPC trials to be phase 1-2 (82.6% vs. 66.7%, P < 0.001), single-arm (51.3% vs. 39.6%, P = 0.020), non-randomized (64.8% vs. 44.4%, P < 0.001), and enroll fewer than 50 participants (46.3% vs. 34.4%, P = 0.015). Blinding was used in 8.8% of NPC immunotherapy trials. Also, 90.7% of NPC immunotherapy trials were recruited nationally and 82.6% were Asia-centric. Although academic institutions and governments (72.7%) were the major sponsors of NPC trials, immunotherapy trials were more likely to be industry-funded than other NPC trials (34.2% vs. 11.5%, P < 0.001). The number of NPC immunotherapy trials increased exponentially after 2017, attributed to the exploration of immune checkpoint inhibitors. Immunotherapy combined with chemotherapy was the most commonly investigated regimen.

Conclusion

NPC immunotherapy trials over a 15-year period were predominantly exploratory. To generate high-quality evidence and advance the clinical application of immunotherapy in NPC, more attention and concerted efforts are needed.

A Pilot Study on Result Reporting Rates from Clinical Trials of Regenerative Medicine

Sharing the methods and results of clinical trials with full transparency is an ethical obligation for those involved in clinical research. In this regard, ClinicalTrials.gov requires reporting of results to the registry within 1 year of completion of the trial. However, a poor result reporting rate has been pointed out, with approximately half the trial results not been reported. It has been suggested that one of the reasons behind this could be the influence of sponsors who conduct the clinical trials. In the course of our previous trend analysis on regenerative medicine for stroke (STR) using ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP) portal site as data sources, we suspected whether the results of gene and/or cell therapy trials are poorly reported. For this reason, a multivariate analysis using data from ClinicalTrials.gov was performed to identify the factors suppressing the result reporting rate, expanding our study to four different kinds of neurological diseases and regenerative medicine as a treatment modality when small-molecule compounds and biologics were set up as controls, in addition to the sponsor type factor. As a result, we found gene and/or cell therapy (therapeutic modality) in addition to STR (disease area), trials completed in 2005-2007, and clinical phases II and IV as independent factors that suppressed the rate of reporting results to ClinicalTrials.gov. On the other hand, big pharmaceutical companies were identified as a factor that increased the reporting result rate to ClinicalTrials.gov. When we applied result reporting publications through PubMed as an index, our study data revealed that the following factors were not identified as the cause for a decrease in the reporting result rate: STR (as disease area), trials completed between 2005 and 2007, and gene/cell therapy (as treatment modality). In this context, our findings indicate that gene/cell therapy has led to the suppression of the result reporting rate to ClinicalTrials.gov. This confirmed our initial suspicion of the low result reporting rate of gene/cell therapy trials. We believe that further studies are required to elucidate the factors affecting the result reporting rate from the perspective of disease area and treatment modality. Impact Statement Several studies have addressed the poor result reporting rate of clinical trials, which still remains an issue. Regenerative medicine holds great promise for the future and the process of its practical application is expected to be challenging. Although having a limited disease area and small sample size, to the best of our knowledge, this is the first study to point out insufficient result reporting of clinical trials of regenerative medicine from the perspective of treatment modality. This report highlights an issue for discussing the path toward its translation through an overview of various factors in comparison with conventional treatment modalities.

Adjuvant immunotherapy in renal cell carcinoma: a systematic review and meta-analysis

OBJECTIVES

To synthesise available data regarding the disease-free survival (DFS) benefit of adjuvant immune checkpoint inhibitors (ICIs) for patients with renal cell carcinoma (RCC) and evaluate the overall safety profile of ICIs in this setting.

MATERIALS AND METHODS

We utilised PubMed, Embase, and relevant conference proceedings to identify phase III randomised controlled trials comparing adjuvant ICIs vs placebo/observation for RCC. The primary outcome of interest was DFS. Variables for subgroup analyses were programmed death-ligand 1 (PD-L1) expression, sarcomatoid features, nephrectomy type, and disease-risk category. Secondary outcomes included Grade ≥3 adverse events (AEs), immune-related AEs, and treatment discontinuation due to AEs. All outcomes were analysed using random-effects models owing to inter-study heterogeneity.

RESULTS

Among the four included studies, one demonstrated a significant DFS benefit. There was considerable clinical and statistical heterogeneity (I2  = 64%) due to differences in inclusion criteria and interventions. While pooled results across the four studies did not demonstrate a significant benefit in DFS overall (hazard ratio [HR] 0.85, 95% confidence interval [CI] 0.69-1.04) there was significant benefit among patients with positive PD-L1 expression (HR 0.72, 95% CI 0.55-0.94) and sarcomatoid features (HR 0.59, 95% CI 0.38-0.91).

CONCLUSION

The evidence base to date regarding ICIs as adjuvant therapy in RCC is mixed - conclusions are limited by considerable heterogeneity between studies. However, pooled analyses suggest that patients with positive PD-L1 expression or sarcomatoid features are most likely to benefit from adjuvant immunotherapy.

Evolving landscape of clinical trials in gastroenteropancreatic neuroendocrine neoplasms in the past two decades

BACKGROUND

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are heterogenous malignancies that require well-designed trials to develop effective management strategies. This cross-sectional study aimed to illustrate the current landscape of clinical trials in GEP-NENs to provide insights for future research.

MATERIALS AND METHODS

We reviewed all clinical trials registered on ClinicalTrials.gov between 1 January 2000 and 31 December 2021 with GEP-NEN in the 'condition or disease' field.

RESULTS

We included 206 eligible trials. Most trials enrolled less than 50 patients (59.8%) and were sponsored by institutions other than government or industry (67.0%). Most trials were conducted in high-income countries (86.6%) and countries located in Europe (30.1%) or Northern America (29.6%). The overall result reporting rates of GEP-NEN trials was 41.4%, and the median time from primary completion to result reporting was 101 months. Characteristics that improved the reporting of results included larger sample size, tumor differentiation specification for inclusion, progression-free survival as primary endpoint, industry sponsorship, and multicenter or multinational participation (all P < 0.05). Compared with trials registered between 2000 and 2011 (n = 28), trials registered between 2012 and 2021 (n = 178) were more likely to specify the Ki-67 index for inclusion (68.0% vs 35.7%, P = 0.002) and to be conducted outside Europe or Northern America (16.4% vs 3.7%, P = 0.02), while the sample size and the sponsorship did not change significantly.

CONCLUSIONS

Novel management options have been explored for GEP-NENs with more specific inclusion criteria during the past two decades. More efforts are needed to promote international collaborations in clinical trials and enhance timely result dissemination.

Early discontinuation and results reporting of robot-assisted surgery studies registered on ClinicalTrials.gov: a research on research study

OBJECTIVES

In this study, we aimed to investigate the characteristics of robot-assisted surgery studies registered on ClinicalTrials.gov and identify factors associated with early trial discontinuation and timely results reporting.

DESIGN

We searched ClinicalTrials.gov to identify interventional studies on robot-assisted surgery on 24 May 2021. All structured information of the potential studies was downloaded and reviewed. A descriptive analysis was performed. Logistic and Cox regression analyses were respectively performed to determine the significance of the association of study characteristics with results reporting and early discontinuation.

RESULTS

A total of 529 interventional studies on robot-assisted surgery were included, with 45 studies reporting results and 54 studies being stopped early. Of the 289 due studies, only 45 (16%) had submitted their results, and only 6 (2%) had submitted their results within the 1-year deadline. Funding source was associated with results reporting: academic funded were 63% less likely than industry to report results (OR=0.37, 95% CI: 0.16 to 0.83, p=0.02). Studies related to device feasibility were associated with greater risk of early discontinuation compared to treatment-related studies (HR=2.30, 95% CI: 1.08 to 4.89, p=0.03). Surprisingly, National Institutes of Health-funded studies were at greater hazard of discontinuation compared to industry-funded studies (HR=3.30, 95% CI: 1.09 to 10.00, p=0.04).

CONCLUSIONS

There was poor compliance with results reporting requirements for robot-assisted surgical studies. It is important that investigators remain informed about the regulatory requirements, and should be helped to develop a sense of responsibility for reporting results. Also, they need to ensure the careful design of the study protocol and adequate resources to reduce the risk of early discontinuation.

Characterization of Oncology Clinical Trials Using Germline Genetic Data

IMPORTANCE

The recent successes of poly-ADP ribose polymerase (PARP) inhibitors and belzutifan support germline genetic data as an exciting, accessible source for biomarkers in cancer treatment. This study hypothesizes, however, that most oncology clinical trials using germline data largely prioritize BRCA1/2 as biomarkers and PARP inhibitors as therapy.

OBJECTIVE

To characterize past and ongoing oncology trials that use germline data.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cross-sectional study of oncology trials used the Informa Trialtrove database to evaluate trial attributes. Trials using germline information (including the terms germline, hereditary, or inherited in the title, treatment plan, interventions, end points, objectives, results, or notes) and conducted globally between December 1, 1990, and April 4, 2022 (data freeze date), were included.

MAIN OUTCOMES AND MEASURES

Trials by cancer type, phase, participants, sponsor type, end points, outcomes, and locations were described. Associated biomarkers and mechanisms of action for studied therapeutic interventions were counted. How germline data in trial inclusion and exclusion criteria are associated with end points, outcomes, and enrollment were also examined.

RESULTS

A total of 887 of 84 297 (1.1%) oncology clinical trials in the Trialtrove database that use germline data were identified. Most trials were conducted in cancer types where PARP inhibitors are already approved. A total of 74.8% (672) of trials were performed in the phase 2 setting or above. Trials were primarily sponsored by industry (523 trials [59.0%]), academia (382 trials [43.1%]), and the government (274 trials [30.9%]), where trials may have multiple sponsor types. Among 343 trials using germline data with outcomes in Trialtrove, 180 (52.5%) reported meeting primary end points. Although BRCA1/2 are the most frequent biomarkers seen (BRCA1, 224 trials [25.3%]; BRCA2, 228 trials [25.7%]), trials also examine pharmacogenomic variants and germline mediators of somatic biomarkers. PARP inhibitors or immunotherapy were tested in 69.9% of trials; PARP inhibition was the most frequently studied mechanism (367 trials [41.4%]). An overwhelming number of trials using germline data were conducted in the US, Canada, and Europe vs other countries, mirroring disparities in cancer genetics data. Germline data in inclusion and exclusion criteria are associated with altered end point, outcomes, and enrollment compared with oncology trials with no germline data use. Examples of inclusion and exclusion criteria regarding germline data that may unintentionally exclude patients were identified.

CONCLUSIONS AND RELEVANCE

These findings suggest that for germline biomarkers to gain clinical relevance, trials must expand biomarkers, therapies, and populations under study.

Racial and ethnic enrollment disparities and demographic reporting requirements in acute leukemia clinical trials

Public demographic reporting for acute leukemia trials is inadequate, and NH-White subjects are more likely to be enrolled.

Larger racial-ethnic enrollment disparities were documented after federal reporting requirements, which may be from more data transparency.

Data regarding racial and ethnic enrollment diversity for acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) clinical trials in the United States are limited, and little is known about the effect of federal reporting requirements instituted in the late 2000s. We examined demographic data reporting and enrollment diversity for ALL and AML trials in the United States from 2002 to 2017, as well as changes in reporting and diversity after reporting requirements were instituted. Of 223 AML trials and 97 ALL trials with results on ClinicalTrials.gov, 68 (30.5%) and 51 (52.6%) reported enrollment by both race and ethnicity. Among trials that reported race and ethnicity (AML, n = 6554; ALL, n = 4149), non-Hispanic (NH)-Black, NH-Native American, NH-Asian, and Hispanic patients had significantly lower enrollment compared with NH-White patients after adjusting for race-ethnic disease incidence (AML odds ratio, 0.68, 0.31, 0.75, and 0.83, respectively; ALL odds ratio, 0.74, 0.27, 0.67, and 0.64; all, P ≤ .01). The proportion of trials reporting race increased significantly after implementation of the reporting requirements (44.2% to 60.2%; P = .02), but race-ethnicity reporting did not (34.8% to 38.6%; P = .57). Reporting proportions according to number of patients enrolled increased significantly after the reporting requirements were instituted (race, 51.7% to 72.7%; race-ethnicity, 39.5% to 45.4%; both, P < .001), and relative enrollment of NH-Black and Hispanic patients decreased (AML odds ratio, 0.79 and 0.77; ALL odds ratio, 0.35 and 0.25; both P ≤ .01). These data suggest that demographic enrollment reporting for acute leukemia trials is suboptimal, changes in diversity after the reporting requirements may be due to additional enrollment disparities that were previously unreported, and enrollment diversification strategies specific to acute leukemia care delivery are needed.