Post-progression treatment in cancer randomized trials: a cross-sectional study of trials leading to FDA approval and published trials between 2018 and 2020

The landscape of checkpoint inhibitors in oncology

BACKGROUND

Immune checkpoint inhibitor (ICI) therapies have become increasingly popular treatment options for patients with cancer, even for patients in non-metastatic settings. Survival and responses have been reported for individual tumor types, but little is known about these outcomes, collectively. We sought to provide an overview of overall survival (OS) and progression-free survival (PFS) in ICI drugs tested in registration trials.

METHODS

In a cross-sectional analysis of US FDA oncology ICI drug approvals (2011-2023), we searched for supporting ICI registration trials. We characterized these trials, regarding differences in median OS and PFS between patients in intervention and control arm participants in ICI registration trials; percentage of patients who receive ICI crossover; and whether there is correlation between the percentage of crossover and differences in OS or PFS.

RESULTS

Fifty-six (54.4 %) approvals had trials that reported median OS for both intervention and control arms (median difference was 2.8 months; IQR: 2.2 to 5.0 months). Sixty-five (63.1 %) approvals had trials that reported PFS data for both arms (median of 0.9 months; IQR: -0.2 to 3.0 months). Subsequent therapy was common (median=18.9 %) and was significantly correlated with a higher difference in median OS in all studies with reported differences (R2 =0.15; p = 0.001).

CONCLUSION

ICIs are increasingly used in the treatment of cancer, yet the median OS improvement is modest, and many ICIs have not been tested for OS benefit. OS is the outcome most meaningful for patients, and drug regulation should require better testing and reporting of these data.

Postrecurrence Treatment in Neoadjuvant or Adjuvant FDA Registration Trials: A Systematic Review

Importance

In oncology randomized clinical trials, suboptimal access to best available care at recurrence (or relapse) may affect overall survival results.

Objective

To assess the proportion and the quality of postrecurrence treatment received by patients enrolled in US Food and Drug Administration (FDA) registration trials of systemic therapy in the adjuvant or neoadjuvant setting.

Evidence Review

For this systematic review, all trials leading to an FDA approval from January 2018 through May 2023 were obtained from the FDA website and drug announcements. Randomized clinical trials of an anticancer drug in the neoadjuvant or the adjuvant setting were included. Trials of supportive care treatment and treatments given in combination with radiotherapy were excluded. Information abstracted for each trial included tumor type, setting, phase, type of sponsor, reporting and assessment of postrecurrence, and overall survival data.

Findings

A total of 14 FDA trials met the inclusion criteria. Postrecurrence data were not available in 6 of 14 registration trials (43%). Of the 8 remaining trials, postrecurrence treatment was assessed as suboptimal in 6 (75%). Overall, only 2 of 14 trials (14%) had data assessed as appropriate.

Conclusions and Relevance

This systematic review found that 43% of randomized clinical trials of anticancer treatment in the adjuvant or neoadjuvant context failed to present any assessable postrecurrence treatment data. In instances in which these data were shared, postrecurrence treatment was suboptimal 75% of the time. The findings suggest that regulatory bodies should enforce rules stipulating that patients have access to the best standard of care at recurrence.

A novel framework to assess haematology and oncology registration trials: The THEOREMM project

BACKGROUND

Methodological limitations affect a significant number of oncology and haematology trials, raising concerns about the applicability of their results. For example, a suboptimal control arm or limited access to best care upon progression may skew the trial results toward a benefit in the experimental arm. Beyond the fact that such limitations do not prevent drugs reaching the market, other assessment tools, such as those developed by professional societies-ESMO-MCBS and ASCO Value Framework-do not integrate these important shortcomings.

METHODS

We propose creating a novel framework with the scope of assessing registration cancer clinical trials in haematology and oncology (randomized or single arm)-that is trials leading to a marketing authorization. The main steps of the methods are (1) assembling a scientific board; (2) defining the scope, goal and methods through pre-specified, pre-registered and protocolized methodology; (3) preregistration of the protocol; (4) conducting a scoping review of limitations and biases affecting oncology trials and assessing existing scores or methods; (5) developing a list of features to be included and assessed within the framework; (6) assessing each feature through a questionnaire sent to highly cited haematologists and oncologists involved in clinical trials; and (7) finalizing the first version of framework.

RESULTS

Not applicable.

CONCLUSIONS

Our proposal emerged in response to the lack of consideration for key limitations in current trial assessments. The goal is to create a framework specifically designed to assess single trials leading to marketing authorization in the field of oncology and haematogy.

Overall survival benefits of cancer drugs initially approved by the US Food and Drug Administration on the basis of immature survival data: a retrospective analysis

BACKGROUND

New cancer drugs can be approved by the US Food and Drug Administration (FDA) on the basis of surrogate endpoints while data on overall survival are still incomplete or immature, with too few deaths for meaningful analysis. We aimed to evaluate whether clinical trials with immature survival data generated evidence of overall survival benefit during the period after marketing authorisation, and where that evidence was reported.

METHODS

In this retrospective analysis, we searched Drugs@FDA to identify cancer drug indications approved between Jan 1, 2001, and Dec 31, 2018, on the basis of immature survival data. We systematically collected publicly available data on postapproval overall survival results in labelling (Drugs@FDA), journal publications (MEDLINE via PubMed), and clinical trial registries (ClinicalTrials.gov). The primary outcome was availability of statistically significant overall survival benefits during the period after marketing authorisation (until March 31, 2023). Additionally, we evaluated the availability and timing of overall survival findings in labelling, journal publications, and ClinicalTrials.gov records.

FINDINGS

During the study period, the FDA granted marketing authorisation to 223 cancer drug indications, 95 of which had overall survival as an endpoint. 39 (41%) of these 95 indications had immature survival data. After a minimum of 4·3 years of follow-up during the period after marketing authorisation (and median 8·2 years [IQR 5·3-12·0] since FDA approval), additional survival data from the pivotal trials became available in either revised labelling or publications, or both, for 38 (97%) of 39 indications. Additional data on overall survival showed a statistically significant benefit in 12 (32%) of 38 indications, whereas mature data yielded statistically non-significant overall survival findings for 24 (63%) indications. Statistically significant evidence of overall survival benefit was reported in either labelling or publications a median of 1·5 years (IQR 0·8-2·3) after initial approval. The median time to availability of statistically non-significant overall survival results was 3·3 years (2·2-4·5). The availability of overall survival results on ClinicalTrials.gov varied considerably.

INTERPRETATION

Fewer than a third of indications approved with immature survival data showed a statistically significant overall survival benefit after approval. Notable inconsistencies in timing and availability of information after approval across different sources emphasise the need for better reporting standards.

FUNDING

None.

Clinical trial design and treatment effects: a meta-analysis of randomised controlled and single-arm trials supporting 437 FDA approvals of cancer drugs and indications

OBJECTIVES

This study aims to analyse the association between clinical trial design and treatment effects for cancer drugs with US Food and Drug Administration (FDA) approval.

DESIGN

Cross-sectional study and meta-analysis.

SETTING

Data from Drugs@FDA, FDA labels, ClincialTrials.gov and the Global Burden of Disease study.

PARTICIPANTS

Pivotal trials for 170 drugs with FDA approval across 437 cancer indications between 2000 and 2022.

MAIN OUTCOME MEASURES

Treatment effects were measured in HRs for overall survival (OS) and progression-free survival (PFS), and in relative risk for tumour response. Random-effects meta-analyses and meta-regressions explored the association between treatment effect estimates and clinical trial design for randomised controlled trials (RCTs) and single-arm trials.

RESULTS

Across RCTs, greater effect estimates were observed in smaller trials for OS (ß=0.06, p<0.001), PFS (ß=0.15, p<0.001) and tumour response (ß=-3.61, p<0.001). Effect estimates were larger in shorter trials for OS (ß=0.08, p<0.001) and PFS (ß=0.09, p=0.002). OS (ß=0.04, p=0.006), PFS (ß=0.10, p<0.001) and tumour response (ß=-2.91, p=0.004) outcomes were greater in trials with fewer centres. HRs for PFS (0.54 vs 0.62, p=0.011) were lower in trials testing the new drug to an inactive (placebo/no treatment) rather than an active comparator. The analysed efficacy population (intention-to-treat, per-protocol, or as-treated) was not consistently associated with treatment effects. Results were consistent for single-arm trials and in multivariable analyses.

CONCLUSIONS

Pivotal trial design is significantly associated with measured treatment effects. Particularly small, short, single-centre trials testing a new drug compared with an inactive rather than an active comparator could overstate treatment outcomes. Future studies should verify results in unsuccessful trials, adjust for further confounders and examine other therapeutic areas. The FDA, manufacturers and trialists must strive to conduct robust clinical trials with a low risk of bias.

A conceptual framework for cautious escalation of anticancer treatment: How to optimize overall benefit and obviate the need for de-escalation trials

BACKGROUND

The developmental workflow of the currently performed phase 1, 2 and 3 cancer trial stages lacks essential information required for the determination of the optimal efficacy threshold of new anticancer regimens. Due to this there is a serious risk of overdosing and/or treating for an unnecessary long time, leading to excess toxicity and a higher financial burden for society. But often post-approval de-escalation trials for dose-optimization and treatment de-intensification are not performed due to failing resources and time. Therefore, the developmental workflow needs to be restructured toward cautious systemic cancer treatment escalation, in order to guarantee optimal efficacy and sustainability.

METHODS

In this manuscript we discuss opportunities to produce the information needed for cautious escalation, based on models of cancer growth and cancer kill kinetics as well as exploratory biomarkers, for the purpose of designing the optimal phase 3 superiority trial. Subsequently, we compare the sample size needed for a phase 3 superiority trial, followed by a necessary de-escalation trial with the sample size needed for a multi-arm phase 3 trial with intervention arms of differing intensity. All essential items are structured within a Framework for Cautious Escalation (FCE). The discussion uses illustrations from the breast cancer setting, but aims to be applicable for all cancers.

RESULTS

The FCE is a promising model of clinical development in oncology to prevent overtreatment and associated issues, especially with regard to the number of repetitive treatment cycles. It will hopefully increase the relevance and success rate of clinical trials, to deliver improved patient-centric outcomes.

Reporting of post-protocol therapies in metastatic breast cancer registration clinical trials: A systematic review

BACKGROUND

As the treatment for metastatic breast cancer (MBC) often includes sequential lines of therapy, data on post-protocol treatment in clinical trials are valuable in the assessment of long-term outcomes. The objective of this study was to assess the reported data on post-protocol therapy in clinical trials supporting US Food and Drug Administration (FDA) approval of drugs for MBC.

METHODS

All initial and subsequent publications related to FDA approved indications for MBC between January 2000 and February 2023 were identified. Collected data included study design, patients' characteristics and whether reporting on post-protocol therapy was available. Differences in study design and population between studies with and without data on post-protocol therapy were evaluated.

FINDINGS

Forty-one indications for MBC were identified. Data were evaluated from 249 publications or abstracts, comprising 20,152 patients. Reporting of post-protocol therapy was available for 22 (53.7 %) indications. Reported data were often incomplete. Reporting has not improved over time with reported data in 50 % and 55.2 % studies between 2000 and 2010 and 2011-2023 (p value for the difference = 1.0), respectively. Studies with OS as their primary endpoints were associated with significantly higher reporting of post-protocol therapy, (p = 0.02). Other characteristics of study design and population were comparable between studies with and without data on post-protocol therapy.

CONCLUSIONS

Data on post-protocol therapy in trials supporting FDA approval of drugs for MBC are available for only half of the indications. As subsequent lines of therapy may have a crucial role in patients' outcome, post-protocol reporting should be included in the regulatory submission and be made available publicly.

How is overall survival assessed in randomised clinical trials in cancer and are subsequent treatment lines considered? A systematic review

BACKGROUND

Overall survival is the "gold standard" endpoint in cancer clinical trials. It plays a key role in determining the clinical- and cost-effectiveness of a new intervention and whether it is recommended for use in standard of care. The assessment of overall survival usually requires trial participants to be followed up for a long period of time. In this time, they may stop receiving the trial intervention and receive subsequent anti-cancer treatments, which also aim to extend survival, during trial follow-up. This can potentially change the interpretation of overall survival in the context of the clinical trial. This review aimed to determine how overall survival has been assessed in cancer clinical trials and whether subsequent anti-cancer treatments are considered.

METHODS

Two searches were conducted using MEDLINE within OVID© on the 9th of November 2021. The first sought to identify papers publishing overall survival results from randomised controlled trials in eight reputable journals and the second to identify papers mentioning or considering subsequent treatments. Papers published since 2010 were included if presenting or discussing overall survival in the context of treating cancer.

RESULTS

One hundred and thirty-four papers were included. The majority of these were presenting clinical trial results (98, 73%). Of these, 45 (46%) reported overall survival as a (co-) primary endpoint. A lower proportion of papers including overall survival as a (co-) primary endpoint compared to a secondary endpoint were published in recent years. The primary analysis of overall survival varied across the papers. Fifty-nine (60%) mentioned subsequent treatments. Seven papers performed additional analysis, primarily when patients in the control arm received the experimental treatment during trial follow-up (treatment switching).

DISCUSSION

Overall survival has steadily moved from being the primary to a secondary endpoint. However, it is still of interest with papers presenting overall survival results with the caveat of subsequent treatments, but little or no investigation into their effect. This review shows that there is a methodological gap for what researchers should do when trial participants receive anti-cancer treatment during trial follow-up. Future research will identify the stakeholder opinions, on how this methodological gap should be addressed.

Is Target-Based Drug Discovery Efficient? Discovery and "Off-Target" Mechanisms of All Drugs

Target-based drug discovery is the dominant paradigm of drug discovery; however, a comprehensive evaluation of its real-world efficiency is lacking. Here, a manual systematic review of about 32000 articles and patents dating back to 150 years ago demonstrates its apparent inefficiency. Analyzing the origins of all approved drugs reveals that, despite several decades of dominance, only 9.4% of small-molecule drugs have been discovered through "target-based" assays. Moreover, the therapeutic effects of even this minimal share cannot be solely attributed and reduced to their purported targets, as they depend on numerous off-target mechanisms unconsciously incorporated by phenotypic observations. The data suggest that reductionist target-based drug discovery may be a cause of the productivity crisis in drug discovery. An evidence-based approach to enhance efficiency seems to be prioritizing, in selecting and optimizing molecules, higher-level phenotypic observations that are closer to the sought-after therapeutic effects using tools like artificial intelligence and machine learning.