When is crossover desirable in cancer drug trials and when is it problematic?

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.

The need for optimal crossover in trials testing the anticipation of treatments: A methodological and ethical issue

Quality of control arms in randomized clinical trials implies also optimal postprotocol treatment. Meta‐research studies highlighting biases of the published literature contribute to improving design and conduct of future studies.

Current unmet needs in locally advanced (unresectable) or metastatic dedifferentiated liposarcoma, the relevance of progression-free survival as clinical endpoint, and expectations for future clinical trial design: an international Delphi consensus report

BACKGROUND

Locally advanced (unresectable) or metastatic dedifferentiated liposarcoma (DDLPS) is a common presentation of liposarcoma. Despite established diagnostic and treatment guidelines for DDLPS, critical clinical gaps remain driven by diagnostic challenges, symptom burden and the lack of targeted, safe and effective treatments. The objective of this study was to gather expert opinions from Europe and the United States on the management, unmet needs and expectations for clinical trial design as well as the value of progression-free survival (PFS) in this disease. Other aims included raising awareness and educate key stakeholders across healthcare systems.

MATERIALS AND METHODS

An international panel of 12 sarcoma key opinion leaders (KOLs) was recruited. The study consisted of two rounds of surveys with pre-defined statements. Experts scored each statement on a 9-point Likert scale. Consensus agreement was defined as ≥75% of experts scoring a statement with ≥7. Revised statements were discussed in a consensus meeting.

RESULTS

Consensus was reached on 43 of 55 pre-defined statements across disease burden, treatment paradigm, unmet needs, value of PFS and its association with overall survival (OS), and cross-over trial design. Twelve statements were deprioritised or merged with other statements. There were no statements where experts disagreed.

CONCLUSION

This study constitutes the first international Delphi panel on DDLPS. It aimed to explore KOL perception of the disease burden and unmet need in DDLPS, the value of PFS, and its potential translation to OS benefit, as well as the relevance of a cross-over trial design for DDLPS therapies. Results indicate an alignment across Europe and the United States regarding DDLPS management, unmet needs, and expectations for clinical trials. Raising awareness of critical clinical gaps in relation to DDLPS can contribute to improving patient outcomes and supporting the development of innovative treatments.

Immunotherapy for Brain Tumors: Where We Have Been, and Where Do We Go From Here?

OPINION STATEMENT

Immunotherapy for glioblastoma (GBM) remains an intensive area of investigation. Given the seismic impact of cancer immunotherapy across a range of malignancies, there is optimism that harnessing the power of immunity will influence GBM as well. However, despite several phase 3 studies, there are still no FDA-approved immunotherapies for GBM. Importantly, the field has learned a great deal from the randomized studies to date. Today, we are continuing to better understand the disease-specific features of the microenvironment in GBM-as well as the exploitable antigenic characteristic of the tumor cells themselves-that are informing the next generation of immune-based therapeutic strategies. The coming phase of next-generation immunotherapies is thus poised to bring us closer to treatments that will improve the lives of patients with GBM.

Common Sense (Radiation) Oncology: Redefining targets in radiotherapy

In 2023, the Common Sense Oncology (CSO) movement was launched with the goal of recalibrating cancer care to focus on outcomes that matter to patients. We extend the three CSO pillars - evidence generation, interpretation and communication - to radiation oncology and advocate for better evidence demonstrating the value of our modality.

Are PARP Inhibitors Ready for Prime Time in Metastatic Prostate Cancer? Maybe Not

While PARP inhibitors such as rucaparib and olaparib have shown activity in metastatic castration-resistant prostate cancer, they have failed to show a clear improvement in hard outcomes such as overall survival or quality of life. Because of methodological limitations, we suggest caution before implementing these treatments in routine clinical practice; offering them to patients without a BRCA1/2 mutation is probably inappropriate.

Validity and Efficiency of Progression-Free Survival-2 as a Surrogate End Point for Overall Survival in Advanced Cancer Randomized Trials

PURPOSE

Progression-free survival (PFS)-2, defined as the time from randomization to progression on second-line therapy, is potentially a more reliable surrogate than PFS for overall survival (OS), but will require longer follow-up and a larger sample size. We sought to compare the validity and efficiency, defined as proportional increase in follow-up time and sample size, of PFS-2 to PFS.

METHODS

We performed an electronic search to identify randomized trials of advanced solid tumors reporting PFS, PFS-2, and OS as prespecified end points. Only studies that had protocols that defined measurement of PFS-2 and follow-up for patients after first disease progression were included. We compared correlations in the relative treatment effect for OS with PFS and PFS-2. We reconstructed individual patient data from survival curves to estimate time to statistical significance (TSS) of the relative treatment effect. We further computed the sample size (person-year [PY] follow-up) required to reach statistical significance.

RESULTS

Across the 42 analysis units and 21,255 patients, the correlation of the relative treatment effect between OS and PFS-2, r, was 0.70 (95% CI, 0.41 to 0.80) and r = 0.46 (95% CI, 0.26 to 0.74) for OS and PFS. The median differences in TSS between OS with PFS, OS with PFS-2, and PFS with PFS-2 were 16.59 (95% CI, 4.48 to not reached [NR]), 10.0 (95% CI, 2.2 to NR), and 4.31 (95% CI, 2.92 to 13.13) months, respectively. The median difference in PYs required to reach statistical significance for PFS-2 over PFS was 156 (95% CI, 82 to 500) PYs, equivalent to an estimated median 12.7% increase in PYs.

CONCLUSION

PFS-2 offers improved correlation with OS than PFS with a modest increase in follow-up time and sample size. PFS-2 should be considered as a primary end point in future trials of advanced cancers.

Clinical trial considerations for pediatric cancer drug development

Oncology has been one of the most active therapeutic areas in medicinal products development. Despite this fact, few drugs have been approved for use in pediatric cancer patients when compared to the number approved for adults with cancer. This disparity could be attributed to the fact that many oncology drugs have had orphan drug designation and were exempt from Pediatric Research Equity Act (PREA) requirements. On August 18, 2017, the RACE for Children Act, i.e. Research to Accelerate Cures and Equity Act, was signed into law as Title V of the 2017 FDA Reauthorization Act (FDARA) to amend the PREA. Pediatric investigation is now required if the drug or biological product is intended for the treatment of an adult cancer and directed at a molecular target that FDA determines to be "substantially relevant to the growth or progression of a pediatric cancer." This paper discusses the specific considerations in clinical trial designs and statistical methodologies to be implemented in oncology pediatric clinical programs.

Challenges, Complexities, and Considerations in the Design and Interpretation of Late-Phase Oncology Trials

Optimal management of cancer patients relies heavily on late-phase oncology randomized controlled trials. A comprehensive understanding of the key considerations in designing and interpreting late-phase trials is crucial for improving subsequent trial design, execution, and clinical decision-making. In this review, we explore important aspects of late-phase oncology trial design. We begin by examining the selection of primary endpoints, including the advantages and disadvantages of using surrogate endpoints. We address the challenges involved in assessing tumor progression and discuss strategies to mitigate bias. We define informative censoring bias and its impact on trial results, including illustrative examples of scenarios that may lead to informative censoring. We highlight the traditional roles of the log-rank test and hazard ratio in survival analyses, along with their limitations in the presence of nonproportional hazards as well as an introduction to alternative survival estimands, such as restricted mean survival time or MaxCombo. We emphasize the distinctions between the design and interpretation of superiority and noninferiority trials, and compare Bayesian and frequentist statistical approaches. Finally, we discuss appropriate utilization of phase II and phase III trial results in shaping clinical management recommendations and evaluate the inherent risks and benefits associated with relying on phase II data for treatment decisions.

Cross-sectional analysis characterizing the use of rank preserving structural failure time in oncology studies: changes to hazard ratio and frequency of inappropriate use

BACKGROUND

Rank preserving structural failure time (RPSFT) is a statistical method to correct or adjust for crossover in clinical trials, by estimating the counterfactual effect on overall survival (OS) when control arm patients do not receive the interventional drug when their tumor progresses. We sought to examine the strength of correlation between differences in uncorrected and corrected OS hazard ratios and percentage of crossover, and characterize instances of fundamental and sequential efficacy.

METHODS

In a cross-sectional analysis (2003-2023), we reviewed oncology randomized trials that used RPSFT analysis to adjust the OS hazard ratio for patients who crossed over to an anti-cancer drug. We calculated the percentage of RPSFT studies evaluating a drug for fundamental efficacy (with or without a standard of care (SOC)) or sequential efficacy and the correlation between the OS hazard ratio difference (unadjusted and adjusted) and the percentage of crossover.

RESULTS

Among 65 studies, the median difference between the uncorrected and corrected OS hazard ratio was -0.1 (quartile 1, quartile 3 : -0.3 to -0.06). The median percentage of crossover was 56% (quartile 1, quartile 3: 37% to 72%). All studies were funded by the industry or had authors who were employees of the industry. Twelve studies (19%) tested a drug's fundamental efficacy when there was no SOC; 34 studies (52%) tested a drug's fundamental efficacy when there was already a SOC; and 19 studies (29%) tested a drug's sequential efficacy. The correlation between the uncorrected and corrected OS hazard ratio difference and the percentage of crossover was 0.44 (95% CI: 0.21 to 0.63).

CONCLUSIONS

RPSFT is a common tactic used by the industry to reinterpret trial results. Nineteen percent of RPSFT use is appropriate. We recognize that while crossover can bias OS results, the allowance and handling of crossover in trials should be limited to appropriate circumstances.

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

BACKGROUND

Suboptimal treatment upon progression may affect overall survival (OS) results in oncology randomized controlled trials (RCTs). We aim to assess the proportion of trials reporting post-progression treatment.

METHODS

This cross-sectional analysis included two concurrent analyses. The first one examined all published RCTs of anti-cancer drugs in six high impact medical/oncology journals between January 2018 and December 2020. The second studied all US Food and Drug Administration (FDA) approved anti-cancer drugs during the same period. Included trials needed to study an anti-cancer drug in the advanced or metastatic setting. Data abstracted included the tumor type, characteristics of trials, and reporting and assessment of post-progression treatment.

RESULTS

There were 275 published trials and 77 US FDA registration trials meeting inclusion criteria. Assessable post-progression data were reported in 100/275 publications (36.4%) and 37/77 approvals (48.1%). Treatment was considered substandard in 55 publications (n = 55/100, 55.0%) and 28 approvals (n = 28/37, 75.7%). Among trials with assessable post-progression data and positive OS results, a subgroup analysis identified substandard post-progression treatment in 29 publications (n = 29/42, 69.0%) and 20 approvals (n = 20/26, 76.9%). Overall, 16.4% of publications (45/275) and 11.7% of registration trials (9/77) had available post-progression data assessed as appropriate.

CONCLUSION

We found that most anti-cancer RCTs do not report assessable post-progression treatment. When reported, post-progression treatment was substandard in most trials. In trials reporting positive OS results and with assessable post-progression data, the proportion of trials with subpar post-progression treatment was even higher. Discrepancies between post-progression therapy in trials and the standard of care can limit RCT results' applicability. Regulatory rules should enforce higher requirements regarding post-progression treatment access and reporting.

Autologous tumor lysate-loaded dendritic cell vaccination in glioblastoma: What happened to the evidence?

In patients with glioblastoma, the "DCVax-L" trial reported a survival benefit with the addition of autologous tumor lysate-loaded denditric cell vaccination to the standard-of-care (SoC) in patients with glioblastoma. The trial presented as a phase 3 externally controlled trial is showing an improvement in overall survival (OS) in patients receiving the vaccine therapy as compared to externally controlled patients, both in the newly diagnosed setting (median OS = 19.3 months versus 16.5 months; HR = 0.80; 98% CI, 0.00-0.94; P = 0.002) and in the recurrent setting (median OS = 13.2 months versus 7.8 months; HR = 0.58; 98% CI, 0.00-0.76; P < 0.001). Interestingly, the original endpoint, progression-free survival (PFS), was not improved by the experimental therapy. While we praise efforts to improve outcomes in a population representing a true unmet need, the trial's design, methods and report raise several issues undermining the ability to derive meaningful conclusion. These limitations are mainly driven by multiple changes occurring years after the trial ended. External controls were used in a trial originally randomizing patients, the primary endpoint was modified (OS instead of PFS), a new study population (recurrent glioblastoma) was added, and unplanned analyses were conducted, among several other changes. Additionally, due to inclusion criteria, the external controls likely selected patients with less favorable outcome as compared with patients enrolled in the trial, potentially biasing the reported survival benefit. In the absence of data sharing, these shortcomings will not be clarified. Dendritic cell vaccination remains a promising approach for GBM. It is therefore disappointing that due to key methodological limitations, the DCVax-L trial ultimately failed to provide sound conclusions about the potential efficacy of such approach for patients with glioblastoma.

Sotorasib in KRASG12C mutated lung cancer: Can we rule out cracking KRAS led to worse overall survival?

The KRAS oncogene is present in up to 25% of solid tumors and for decades had been undruggable. Sotorasib was the first-in-class KRAS inhibitor to reach the US and European market, and its pharmacological inhibition is restricted to the KRAS p.G12C mutation. Sotorasib showed activity (tumor shrinkage) in patients with non-small cell lung cancer harboring this specific mutation, and efficacy was tested in the CodeBreaK 200, open-label, phase 3 trial (NCT04303780). The results were presented in the ESMO 2022 meeting. CodeBreaK 200 found an improvement in the primary endpoint of progression-free survival (PFS), but overall survival, a key secondary endpoint, was not improved. However, critical questions about the trial's design may limit inferences regarding the reported results. The control arm treatment was inferior to the best standard of care. A late protocol modification (which lowered the sample size and allowed a problematic crossover) prohibited the trial from making a determination regarding overall survival. Imbalance in censoring rates, with potential informative censoring, makes PFS estimates unreliable. Quality-of-life data were also limited. Ultimately, CodeBreaK 200 does not clarify how this therapy should be used in practice, and while we maintain cautious enthusiasm for this and other Ras inhibitors, we await more informative trials.

Surrogate Endpoints as Predictors of Overall Survival in Metastatic Urothelial Cancer: A Trial-level Analysis

Background

Surrogate endpoints (SEs), such as progression-free survival (PFS) and objective response rate (ORR), are frequently used in clinical trials. The relationship between SEs and overall survival (OS) has not been well described in metastatic urothelial cancer (MUC).

Objective

We evaluated trial-level data to assess the relationship between SEs and OS. We hypothesize a moderate surrogacy relationship between both PFS and ORR with OS.

Design setting and participants

We systematically reviewed phase 2/3 trials in MUC with two or more treatment arms, and report PFS and/or ORR, and OS.

Outcome measurements and statistical analysis

Linear regression was performed, and the coefficient of determination (R²) and surrogate threshold effect (STE) estimate were determined between PFS/ORR and OS.

Results and limitations

Of 3791 search results, 59 trials and 62 comparisons met the inclusion criteria. Of the 53 trials that reported PFS, 31 (58%) reported proportional hazard regression for PFS and OS. Linear regression across trials demonstrated an R² of 0.60 between hazard ratio (HR) for PFS (HR^PFS) and HR for OS (HR^OS), and an STE of 0.41. Linear regression of ΔPFS (median PFS in months of the treatment arm - that of the control arm) and ΔOS demonstrated an R² of 0.12 and an STE of 14.1 mo. Thirty trials reported ORRs. Linear regression for ORR^ratio and HR^OS among all trials found an R² of 0.08; an STE of 95% was not reached at any value and ΔORR and HR^OS similarly demonstrated a poor correlation with an R² value of 0.03.

Conclusions

PFS provides only a moderate level of surrogacy for OS; An HR^PFS of ≤0.41 provides 95% confidence of OS improvement. ORR is weakly correlated with OS and should be de-emphasized in MUC clinical trials. When PFS is discussed, proportional hazard regression should be reported.

Patient summary

We examined the relationship between surrogate endpoints, common outcomes in clinical trials, with survival in urothelial cancer trials. Progression-free survival is moderately correlated, while objective response rate had a poor correlation with survival and should be de-emphasized as a primary endpoint.

Crossover in Adjuvant Trastuzumab Trials: Sparing Toxicity in Patient Care

OBJECTIVES

Design and reporting of randomized control trials for drug therapies in the adjuvant setting require a nuanced consideration of patient crossover. Adjuvant trials can be susceptible to the misuse of crossover and may distort the interpretation of findings. We sought to investigate and describe crossover and/or postprogression access to trastuzumab within adjuvant trastuzumab randomized control trials for human epidermal growth factor receptor 2-positive breast cancer patients.

METHODS

Seven clinical trials for adjuvant trastuzumab in human epidermal growth factor receptor 2-positive breast cancer were identified through a meta-analysis published in the Lancet . Primary study publications were located through MEDLINE, Google Scholar, and trials were identified, when possible, using Clincialtrials.gov.

RESULTS

Sixteen publications, describing 7 studies, were reviewed. Four (57%) trials reported offering patients within the control arm the opportunity to crossover and receive trastuzumab in the adjuvant setting. Two (29%) trials did not report nor discuss crossover within the publication. Five (71%) trials reported the total number of patients who crossed over among the control arms. No trials specified the proportion of control patients who received trastuzumab at recurrence.

CONCLUSIONS

Trials for adjuvant trastuzumab did not disambiguate between crossover (1) in the adjuvant setting or (2) at recurrence. Due to the low reported rate of crossover, it is questionable if participants received the standard of care.

Dose modification rules and availability of growth factor support: A cross-sectional study of head-to-head cancer trials used for US FDA approval from 2009 to 2021

AIM OF THE STUDY

Different drug modification rules or growth factor support guidance may affect the results in oncology randomised controlled trials. We aimed to estimate the prevalence of unequal rules for dose modification rules or the use of myeloid growth factors in head-to-head registration Food and Drug Administration trials.

METHODS

This cross-sectional analysis included all head-to-head registration randomised controlled trials leading to a US Food and Drug Administration approval between 2009 and 2021. Trials examined anti-cancer drugs in the advanced or metastatic setting where a comparison could be made between arms regarding either dose modification rules or myeloid growth factors recommendations. Sixty-two registration trials met inclusion criteria. Information abstracted for each trial included tumour type, setting, phase, and type of sponsor. We assessed, according to pre-specified rules, imbalance in drug modification rules, myeloid growth factors recommendations or both.

RESULTS

We find 40 of 62 (65%) selected trials have unequal rules for dose medication, granulocyte colony-stimulating factor (G-CSF) use or both. Six trials (10%) had rules favouring the control arm, while 55% of selected trials (34/62) favoured the experimental arm. Among these, 50% (17/34) had unequal drug modification rules, 41% (14/34) had unequal G-CSF rules and 9% contained both (3/34).

CONCLUSION

We find that 55% of trials testing anti-cancer drugs against each other used protocol rules that favoured the experimental arm. This leaves open the question of whether new molecules are truly superior to older molecules or if instead different outcomes are due to more aggressive dosing or growth factor support. Trials should utilise equal rules for dose medication and G-CSF support.

Clinical Benefit Scales and Trial Design: Some Statistical Issues

Recently developed clinical-benefit outcome scales by the European Society for Medical Oncology (ESMO) and the American Society of Clinical Oncology (ASCO) allow standardized objective evaluation of outcomes of randomized clinical trials. However, incorporation of clinical-benefit outcome scales into trial designs highlights a number of statistical issues: the relationship between minimal clinical benefit and the target treatment-effect alternative used in the trial design, designing trials to assess long-term benefit, potential problems with using a trial endpoint that is not overall survival, and how to incorporate subgroup analyses into the trial design. Using the ESMO Magnitude of Clinical Benefit Scale as a basis for discussion, we review what these issues are and how they can guide the choice of trial-design target effects, appropriate endpoints, and pre-specified subgroup analyses to increase the chances that the resulting trial outcomes can be appropriately evaluated for clinical benefit.

Vaccine Therapy in Non-Small Cell Lung Cancer

Immunotherapy using immune checkpoint modulators has revolutionized the oncology field, emerging as a new standard of care for multiple indications, including non-small cell lung cancer (NSCLC). However, prognosis for patients with lung cancer is still poor. Although immunotherapy is highly effective in some cases, not all patients experience significant or durable responses, and further strategies are needed to improve outcomes. Therapeutic cancer vaccines are designed to exploit the body’s immune system to activate long-lasting memory against tumor cells that ensure tumor regression, with minimal toxicity. A unique feature of cancer vaccines lies in their complementary approach to boost antitumor immunity that could potentially act synergistically with immune checkpoint inhibitors (ICIs). However, single-line immunization against tumor epitopes with vaccine-based therapeutics has been disappointingly unsuccessful, to date, in lung cancer. The high level of success of several recent vaccines against SARS-CoV-2 has highlighted the evolving advances in science and technology in the vaccines field, raising hope that this strategy can be successfully applied to cancer treatments. In this review, we describe the biology behind the cancer vaccines, and discuss current evidence for the different types of therapeutic cancer vaccines in NSCLC, including their mechanisms of action, current clinical development, and future strategies.

Tivozanib in renal cell carcinoma: a systematic review of the evidence and its dissemination in the scientific literature

Background

Tivozanib (Fotivda) is an anti-angiogenic tyrosine kinase inhibitor that was denied access to the US market by the Food and Drug Administration (FDA). In contrast, it was granted approval by the European Medicines Agency (EMA) for the treatment of Renal Cell Carcinoma in adults. Given the conflicting decisions from these regulatory agencies, the objectives of the following study are (i) to critically review the evidence supporting the approval of tivozanib; (ii) to analyse the dissemination of this evidence in the literature by way of a citation analysis.

Methods

Pivotal trials were searched by two independent reviewers using Medline, Cochrane Library, ClinicalTrials.gov and the European Public Assessment Report. The risk of bias for each trial was then inductively assessed. Articles citing any of these trials were identified using Web of Sciences. Finally, the quality of the citations was evaluated by two independent reviewers according to standard data extraction methods.

Results

The search for primary evidence identified two pivotal studies: TIVO-1 upon which the FDA and the EMA decisions were based, and TIVO-3 which was conducted after the agencies’ decisions had been issued. The TIVO-1 trial presented several limitations that compromised causal inference, in relation to (i) design (absence of blinding, inappropriate comparator, and one-way crossover), (ii) poor internal consistency in the results for the primary endpoint, (iii) a discrepancy between a benefit observed for progression-free survival (HR: 0.80, 95% CI [0.64–0.99]) and the absence of difference for overall survival (HR: 1.25, 95% CI [0.95 – 1.62]). Our citation search protocol identified 229 articles that cited TIVO-1 in the 7 years following its publication, among which 151 (65.9%) citing articles discussing efficacy. Presence of spin was identified in 64 (42.4%) of these 151 citing articles, and 39 (25.8%) additional articles citing results without providing enough elements to interpret the TIVO-1 results.

Conclusion

EMA’s approval was based on a single pivotal trial presenting critical limitations, rendering the results from the trial potentially inconclusive. The broad dissemination of TIVO-1 results in the scientific literature may have been affected by spin or results were presented in an inadequate critical manner.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09475-7.

11 ESMO 2021 breakthroughs: practicing oncologist’s perceptions on data presentation

Background

The European Society for Medical Oncology (ESMO) 2021 conference provided a high number of randomized phase III trial reports, many of which were claimed to be practice changing. Given the short time available for conference presentations, results and conclusions tend to have greatest priority with less time remaining for study background and study methodology.

Purpose

On behalf of the ESMO Practicing Oncologists Working Group, 11 potentially practice-changing reports were selected and screened for three main questions: (i) Did the investigators provide sufficient details with regard to Patients and Methods to make the results comprehensible? (ii) Were there any reasons to consider bias? (iii) To which extent did the results presented translate to clinical benefit?

Results

In 2 out of 11 trials, the study design presented differed considerably from the study design described at ClinicalTrials.gov. Allocation concealment was not carried out in 6 out of 11 trials. In none of the trials reporting progression-free survival was informative censoring considered an issue. In none of the trials reporting overall survival was desirable crossover considered an issue. Defined trial outcome measures depicted at ClinicalTrials.gov, which could boost or weaken the ESMO-Magnitude of Clinical Benefit Scale score, were often lacking in the presentation. Study success was claimed in a heterogeneous manner, which was often not clearly linked to overall clinical benefit.

Conclusion

ESMO conference presentations can inform the scientific community and catalyze further research but cannot replace the full papers in peer-reviewed journals, which are needed to estimate the thoroughness of the results, the overall impact on clinical benefit and the consequences for future treatment guidelines.

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An oncological peer-reviewed paper is lengthy and well structured.

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An oncological conference presentation is short and less structured, but its impact can be high.

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ESMO 2021 conference encompassed many possibly practice-shaping phase III trial reports.

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A survey of 11 selected reports to ascertain if the conclusions made were adequately underlined by the provided information.

N-of-1 Trials in Pediatric Oncology: From a Population-Based Approach to Personalized Medicine-A Review

Pediatric oncology is a critical area where the more efficient development of new treatments is urgently needed. The speed of approval of new drugs is still limited by regulatory requirements and a lack of innovative designs appropriate for trials in children. Childhood cancers meet the criteria of rare diseases. Personalized medicine brings it even closer to the horizon of individual cases. Thus, not all the traditional research tools, such as large-scale RCTs, are always suitable or even applicable, mainly due to limited sample sizes. Small samples and traditional versus subject-specific evidence are both distinctive issues in personalized pediatric oncology. Modern analytical approaches and adaptations of the paradigms of evidence are warranted. We have reviewed innovative trial designs and analytical methods developed for small populations, together with individualized approaches, given their applicability to pediatric oncology. We discuss traditional population-based and individualized perspectives of inferences and evidence, and explain the possibilities of using various methods in pediatric personalized oncology. We find that specific derivatives of the original N-of-1 trial design adapted for pediatric personalized oncology may represent an optimal analytical tool for this area of medicine. We conclude that no particular N-of-1 strategy can provide a solution. Rather, a whole range of approaches is needed to satisfy the new inferential and analytical paradigms of modern medicine. We reveal a new view of cancer as continuum model and discuss the "evidence puzzle".

Use of Second-line Immunotherapy in Control Arms of Randomized Clinical Trials in Kidney Cancer: A Systematic Review

IMPORTANCE

Immunotherapy (anti-programmed death ligand 1 antibodies) is associated with improved survival rates in advanced kidney cell carcinoma (KCC) after progression on first-line tyrosine kinase inhibitor (TKI) treatment. It is unknown whether and to what degree patients in the control arm receive postprotocol immunotherapy in trials comparing combination immunotherapy regimens with TKI in first-line advanced KCC.

OBJECTIVE

To characterize the proportion of patients in the control arm who received postprotocol immunotherapy in trials comparing combination immunotherapy regimens with TKI in first-line advanced KCC.

EVIDENCE REVIEW

A search of PubMed was conducted to identify randomized clinical trials of combination immunotherapy compared with TKI in first-line advanced KCC between January 1, 2015, and February 28, 2021. Combination immunotherapy was defined as an anti-programmed death ligand 1 agent and an additional agent. Search terms included renal cell cancer and first-line and were filtered by the type clinical trial. All English-language trials of combination immunotherapy compared with a TKI were included. The trials and their protocols and supplements were analyzed to determine the proportion of patients in the control arm receiving postprotocol immunotherapy.

FINDINGS

A total of 106 articles met search criteria and were screened. A total of 6 trials and 3 published updates of trial results were included in the systematic review. Of 2565 patients assigned to control arm groups, 2069 (81%) were no longer on TKI at last data cutoff. Of patients in the control arm who discontinued TKI, 932 (45%) received postprotocol immunotherapy. Of patients in the control arm receiving any type of postprotocol therapy, 66.4% received immunotherapy.

CONCLUSIONS AND RELEVANCE

This systematic review found that the proportion of patients in the control arm receiving postprotocol immunotherapy is low in randomized clinical trials of first-line combination immunotherapy regimens for advanced KCC. Appropriate use of postprotocol therapy is essential to answering the question of whether a combination or sequential treatment strategy with immunotherapy is superior.

Biases in study design, implementation, and data analysis that distort the appraisal of clinical benefit and ESMO-Magnitude of Clinical Benefit Scale (ESMO-MCBS) scoring

Background

The European Society for Medical Oncology-Magnitude of Clinical Benefit Scale (ESMO-MCBS) is a validated, widely used tool developed to score the clinical benefit from cancer medicines reported in clinical trials. ESMO-MCBS scores assume valid research methodologies and quality trial implementation. Studies incorporating flawed design, implementation, or data analysis may generate outcomes that exaggerate true benefit and are not generalisable. Failure to either indicate or penalise studies with bias undermines the intention and diminishes the integrity of ESMO-MCBS scores. This review aimed to evaluate the adequacy of the ESMO-MCBS to address bias generated by flawed design, implementation, or data analysis and identify shortcomings in need of amendment.

Methods

As part of a refinement of the ESMO-MCBS, we reviewed trial design, implementation, and data analysis issues that could bias the results. For each issue of concern, we reviewed the ESMO-MCBS v1.1 approach against standards derived from Helsinki guidelines for ethical human research and guidelines from the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use, the Food and Drugs Administration, the European Medicines Agency, and European Network for Health Technology Assessment.

Results

Six design, two implementation, and two data analysis and interpretation issues were evaluated and in three, the ESMO-MCBS provided adequate protections. Seven shortcomings in the ability of the ESMO-MCBS to identify and address bias were identified. These related to (i) evaluation of the control arm, (ii) crossover issues, (iii) criteria for non-inferiority, (iv) substandard post-progression treatment, (v) post hoc subgroup findings based on biomarkers, (vi) informative censoring, and (vii) publication bias against quality-of-life data.

Conclusion

Interpretation of the ESMO-MCBS scores requires critical appraisal of trials to understand caveats in trial design, implementation, and data analysis that may have biased results and conclusions. These will be addressed in future iterations of the ESMO-MCBS.

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We reviewed trial design, implementation, and data analysis issues that could bias the results of trials.

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These issues could skew the results of ESMO-MCBS scores.

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Six design, two implementation, and two analysis issues were reviewed, and seven shortcomings were identified.

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These issues will be addressed in future versions of the MCBS scale.

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Interpretation of MCBS scores requires critical appraisal of trials.

Reporting of Postprotocol Therapies and Attrition in Multiple Myeloma Randomized Clinical Trials: A Systematic Review

Importance

A thorough understanding of the optimal role and sequence of agents for treatment of multiple myeloma (MM) requires knowledge of the use and rate of postprotocol therapies in randomized clinical trials (RCTs).

Objectives

To examine the proportion of MM RCTs that reported postprotocol therapies and, among those, the percentage of patients who received no further therapy and how treatments differed between the control and intervention arms.

Evidence Review

The reporting of postprotocol therapies was systematically assessed in published MM RCTs using 3 databases (PubMed, Embase, and Cochrane Registry of Controlled Trials) for MM RCTs from January 1, 2005, to December 30, 2019. All MM RCTs were included, and all other studies, such as editorials, nonrandomized studies, and review articles, were excluded.

Findings

A total of 103 RCTs were identified (47 251 patients); of these, 45 (43.7%) reported subsequent treatments in that publication or in any subsequent publication. Trials funded by pharmaceutical companies (26 of 47 [55.3%]) were more likely to report subsequent treatments than cooperative group studies (19 of 56 [33.9%]) (χ21,103 = 4.8; P = .03). Differences were found in the treatments received between the intervention and control arms of RCTs. When data were reported, 5150 of 9351 patients (54.9%) in RCTs of newly diagnosed MM and 2197 of 4501 patients (48.8%) in RCTs of relapsed/refractory MM received any subsequent therapy.

Conclusions and Relevance

Postprotocol therapies in MM RCTs are often not reported and, when they are, many patients receive no further therapy. Reporting guidelines for postprotocol therapies are needed.

Untangling the PROfound Trial for Advanced Prostate Cancer: Is There Really a Role for Olaparib?

The phase 3 PROfound trial led to the recent approval of the PARP inhibitor olaparib for men with metastatic castration-resistant prostate cancer and mutations in homologous recombination repair genes. We raise methodological concerns about the trial, including: a suboptimal control arm, problematic use of crossover, use of radiographic progression-free survival as the primary endpoint, and ambiguous benefit for patients with mutations in homologous recombination repair genes other than BRCA1, BRCA2, and ATM.

Trends in the crossover of patients in phase III oncology clinical trials in the USA

Background

The incorporation of crossover in randomised controlled trials is accepted as an ethical obligation, especially in cancer clinical trials. The more common type of crossover is crossover allowance, which allows patients assigned to one arm to switch to another arm if there is an established benefit in the crossover arm. In contrast, crossover-designed studies involve switching patients from all arms to a different arm as part of the study design. Crossover allowance may have advantages in patient recruitment and incorporating crossover after initial positive results fulfil ethical requirements. However, crossover can also contribute to confounding major endpoints of studies, such as overall survival or the second progression-free survival interval. For this reason, it is important to investigate and identify potential trends of crossover in clinical trials testing novel therapies.

Methods

Data about cancer clinical trials were extracted from clinicaltrials.gov. The search query was limited to completed phase III studies in adult populations. Location was limited to the USA. Date range extended from 1990 to 2019. Search query included the terms: cancer; completed- recruitment status; age: 18–65+ years; sex: all; location: USA; and study phase: phase 3. Studies were then excluded if they were not randomised controlled trials (RCTs) with the primary purpose of treatment and if they did not test cancer-related interventions.

Results

A total of 744 clinical trials were identified. There were 459 RCTs aimed at treatment, and of those, 35 utilised crossover. The start dates of these crossover trials ranged from 1997 to 2012. Thirty studies utilised crossover allowance. Prostate, breast and gastrointestinal stromal tumour cancers were the most represented cancer types in crossover studies. Among the 30 studies, the median proportion of patients who crossed over relative to the original arm assignment ranged from 2% to 88%, with a median of 57.5%.

Conclusions

The proportion of identified clinical trials with crossover compared to those without is extremely small. Crossover in clinical trials studying cancer treatment does not appear to be a widespread practice. Even though statistical approaches to mitigate confounding exist, crossover can still skew accurate reporting of the impact of experimental therapies on overall survival.

Limitations in Clinical Trials Leading to Anticancer Drug Approvals by the US Food and Drug Administration

IMPORTANCE

While there have been multiple assessments of clinical trials leading to anticancer drug approvals by the US Food and Drug Administration (FDA), the cumulative percentage of approvals based on trials with a limitation remains uncertain.

OBJECTIVE

To assess the percentage of clinical trials with limitations in 4 domains-lack of randomization, lack of significant overall survival advantage, inappropriate use of crossover, and use of suboptimal control arms-that led to FDA approvals from June 30, 2014, to July 31, 2019.

DESIGN, SETTING, AND PARTICIPANTS

This observational analysis included all anticancer drug indications approved by the FDA from June 30, 2014, through July 31, 2019. All indications were investigated, and each clinical trial was evaluated for design, enrollment period, primary end points, and presence of a limitation in the domains of interest. The standard-of-care therapy was determined by evaluating the literature and published guidelines 1 year prior to the start of clinical trial enrollment. Crossover was examined and evaluated for optimal use. The percentage of approvals based on clinical trials with any or all limitations of interest was then calculated.

MAIN OUTCOMES AND MEASURES

Estimated percentage of clinical trials with limitations of interest that led to an anticancer drug marketing authorization by the FDA.

RESULTS

A total of 187 trials leading to 176 approvals for 75 distinct novel anticancer drugs by the FDA were evaluated. Sixty-four (34%) were single-arm clinical trials, and 123 (63%) were randomized clinical trials. A total of 125 (67%) had at least 1 limitation in the domains of interest; 60 of the 125 trials (48%) were randomized clinical trials. Of all 123 randomized clinical trials, 37 (30%) lacked overall survival benefit, 31 (25%) had a suboptimal control, and 17 (14%) used crossover inappropriately.

CONCLUSIONS AND RELEVANCE

Two-thirds of cancer drugs are approved based on clinical trials with limitations in at least 1 of 4 essential domains. Efforts to minimize these limitations at the time of clinical trial design are essential to ensure that new anticancer drugs truly improve patient outcomes over current standards.