The misguided ethics of crossover trials

[Translated article] Characteristics, clinical benefit, and reimbursement of new authorisations for oncohaematology drugs in Spain between 2017 and 2020

OBJECTIVE

To describe the authorisations and funding resolutions for new onco-haematological drugs in Spain between 2017 and 2020, as well as the results of their main trials.

METHODS

Observational, cross-sectional, descriptive study conducted between October and December 2022. Onco-haematology drugs approved by the European Medicines Agency between 2017 and 2020 were included, according to EFPIA patients W.A.I.T Indicator 2021 Survey. Authorisation information was obtained from the main study of the European Public Assessment Report. Data were collected on medicines, their authorisation and main study, benefit shown, cost, and status and time to reimbursement.

RESULTS

Forty-one new drugs authorised for 49 indications were identified. More than half (58.5%) were targeted therapies, and 61.2% were for the treatment of solid tumours (61.2%). Most had palliative intent (71.4%) and were indicated in relapsed or refractory disease (55.1%). Of the clinical trials, 57.1% were phase III and 63.3% were randomised. The primary endpoint was overall survival in 16.3%, increasing to 25.8% among randomised clinical trials. Regarding licensed drugs based on response rate, the median response rate was 56.4% [IQI 40-66.3]. In those authorised on the basis of surrogate time-to-event endpoints, the median hazard ratio was 0.54 [IQI 0.38-0.57], and among those using overall survival was 0.71 [IQI 0.59-0.77]. Globally, 22.4% had shown benefit in overall survival, with a median gain of 4 months [IQI 3.6-16.7]. One-third (33.3%) of the indications evaluable according to the European Society for Medical Oncology Magnitude of Clinical Benefit Scale showed substantial clinical benefit. Of the indications, 75.5% were funded, half (48.6%; 36.7% of the total) with restrictions. The median time to funding was 19.5 months [IQI 11.4-29.3].

CONCLUSIONS

Most main clinical trials of new onco-haematology drugs approved in Spain used surrogate primary endpoint and, at the time of authorisation, few had shown to prolong overall survival. More than a third were uncontrolled clinical trials.

Characteristics, clinical benefit and reimbursement of new authorisations for oncohaematology drugs in Spain between 2017 and 2020

OBJECTIVE

To describe the authorisations and funding resolutions for new onco-hematological drugs in Spain between 2017 and 2020, as well as the results of their main trials.

METHODS

Observational, cross-sectional, descriptive study conducted between October and December 2022. Onco-hematology drugs approved by the European Medicines Agency between 2017 and 2020 were included, according to EFPIA patients W.A.I.T Indicator 2021 Survey. Authorisation information was obtained from the main study of the European Public Assessment Report (EPAR). Data were collected on medicines, their authorisation and main study, benefit shown, cost, and status and time to reimbursement.

RESULTS

Forty-one new drugs authorised for 49 indications were identified. More than half (58.5%) were targeted therapies, and 61.2% were for the treatment of solid tumors (61.2%). Most had palliative intent (71.4%) and were indicated in relapsed or refractory disease (55.1%). Of the clinical trials, 57.1% were phase III and 63.3% were randomised. The primary endpoint was overall survival in 16.3%, increasing to 25.8% among randomised clinical trials. Regarding licensed drugs based on response rate, the median response rate was 56.4% (IQI 40.0-66.3). In those authorised on the basis of surrogate time-to-event endpoints, the median Hazard Ratio was 0.54 (IQI 0.38-0.57), and among those using overall survival was 0.71 (IQI 0.59-0.77). Globally, 22.4% had shown benefit in overall survival, with a median gain of 4 months (IQI 3.6-16.7). One third (33.3%) of the indications evaluable according to the European Society for Medical Oncology Magnitude of Clinical Benefit Scale showed substantial clinical benefit. Of the indications, 75.5% were funded, half (48.6%; 36.7% of the total) with restrictions. The median time to funding was 19.5 months (IQI 11.4-29.3).

CONCLUSIONS

Most main clinical trials of new onco-haematology drugs approved in Spain used surrogate primary endpoint and, at the time of authorisation, few had shown to prolong overall survival. More than a third were uncontrolled clinical trials.

ACTION: a randomized phase 3 study of ONC201 (dordaviprone) in patients with newly diagnosed H3 K27M-mutant diffuse glioma

BACKGROUND

H3 K27M-mutant diffuse glioma primarily affects children and young adults, is associated with a poor prognosis, and no effective systemic therapy is currently available. ONC201 (dordaviprone) has previously demonstrated efficacy in patients with recurrent disease. This phase 3 trial evaluates ONC201 in patients with newly diagnosed H3 K27M-mutant glioma.

METHODS

ACTION (NCT05580562) is a randomized, double-blind, placebo-controlled, parallel-group, international phase 3 study of ONC201 in newly diagnosed H3 K27M-mutant diffuse glioma. Patients who have completed standard frontline radiotherapy are randomized 1:1:1 to receive placebo, once-weekly dordaviprone, or twice-weekly dordaviprone on 2 consecutive days. Primary efficacy endpoints are overall survival (OS) and progression-free survival (PFS); PFS is assessed by response assessment in neuro-oncology high-grade glioma criteria (RANO-HGG) by blind independent central review. Secondary objectives include safety, additional efficacy endpoints, clinical benefit, and quality of life. Eligible patients have histologically confirmed H3 K27M-mutant diffuse glioma, a Karnofsky/Lansky performance status ≥70, and completed first-line radiotherapy. Eligibility is not restricted by age; however, patients must be ≥10 kg at time of randomization. Patients with a primary spinal tumor, diffuse intrinsic pontine glioma, leptomeningeal disease, or cerebrospinal fluid dissemination are not eligible. ACTION is currently enrolling in multiple international sites.

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.

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.

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.

Design of placebo-controlled randomized trials of anticancer agents: Ethical considerations based on a review of published trials

BACKGROUND

Limited information exists about the design of placebo-controlled cancer trials. Through a systematic review of trials published in 2013, we describe placebo use in randomized trials testing anticancer agents and analyze strategies that increase exposure to the experimental regimen.

METHODS

Trials were classified as add-on (placebo in combination with standard treatment) or placebo-only. Strategies to allow more than half of the participants to receive the experimental regimen were reviewed. The risk-benefit ratio of receiving the experimental agent was considered favorable if the difference in primary outcome was significant (p ≤ 0.05), neutral if there was no significant difference in the primary outcome and the experimental agent did not add substantial toxicity, and unfavorable otherwise.

RESULTS

Eighty trials were included (32,694 participants). Most trials were add-on (69%). The risk-benefit outcome was favorable, neutral, and unfavorable to the experimental agent in 52%, 32%, and 16% of placebo-only trials and 25%, 53%, and 22%, respectively, of add-on trials. Four strategies increased exposure to the experimental regimen: one-way crossover (23%), uneven randomization (21%), three-arms (13%), and randomized discontinuation design (4%); these strategies were used more often in placebo-only trials.

CONCLUSION

A minority of participants received placebo alone and strategies to increase experimental exposure were used commonly. Fewer than half of the studies had favorable outcomes, thus defending the use of placebo controls, when there is no established treatment. Strategies that increase patient exposure to experimental agents rather than placebo may expose them to non-beneficial, sometimes toxic, experimental agents.

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.

•

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.

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.

Progression-free survival is a suboptimal predictor for overall survival among metastatic solid tumour clinical trials

BACKGROUND

The use of overall survival (OS) as the gold standard primary end-point (PEP) in metastatic oncologic randomised controlled trials (RCTs) has declined in favour of progression-free survival (PFS) without a complete understanding of the degree to which PFS reliably predicts for OS.

METHODS

Using ClinicalTrials.gov, we identified 1239 phase III oncologic RCTs, 260 of which were metastatic solid tumour trials with a superiority-design investigating a therapeutic intervention by using either a PFS or OS PEP. Each individual trial was reviewed to quantify RCT design factors and disease-related outcomes.

RESULTS

A total of 172,133 patients were enrolled from the year 1999 to 2015 in RCTs that used PFS (56.2%, 146/260) or OS (43.8%, 114/260) as the PEP. PFS trials were more likely to restrict patient eligibility by using molecular criteria (15.1% versus 4.4%, p = 0.005) use targeted therapy (80.1% versus 67.5%, p = 0.048), accrue fewer patients (median 495 versus 619, p = 0.03), and successfully meet the trial PEP (66.9% versus 33.3%, p < 0.0001). On multiple binary logistic regression analysis, factors that predicted for PFS or OS PEP trial success included choice of PFS PEP (p < 0.0001), molecular profile restriction (p = 0.02) and single agent therapy (p = 0.02). Notably, there was only a 38% (31/82) conversion rate of positive PFS-to-OS benefit; lack of industry sponsorship predicted for PFS-to-OS signal conversion (80.0% without industry sponsorship versus 35.1% with industry sponsorship, p = 0.045).

CONCLUSIONS

A PFS PEP has suboptimal positive predictive value for OS among phase III metastatic solid tumour RCTs. Regulatory agency decisions should be judicious in using PFS results as the primary basis for approval.

Systematic Review of Research Methods and Reporting Quality of Randomized Clinical Trials of Spinal Cord Stimulation for Pain

This systematic review assessed design characteristics and reporting quality of published randomized clinical trials of spinal cord stimulation (SCS) for treatment of pain in adults and adolescents. The study protocol was registered with PROSPERO (CRD42018090412). Relevant articles were identified by searching the following databases through December 31, 2018: MEDLINE, Embase, WikiStim, The Cochrane Database of Systematic Reviews, and The Cochrane Central Register of Controlled Trials. Forty-six studies were included. Eighty-seven percent of articles identified a pain-related primary outcome. Secondary outcomes included physical functioning, health-related quality of life, and reductions in opioid use. Nineteen of the 46 studies prespecified adverse events as an outcome, with 4 assessing them as a primary outcome. Eleven studies stated that they blinded participants. Of these, only 5 were assessed as being adequately blinded. The number of participants enrolled was generally low (median 38) and study durations were short (median 12 weeks), particularly in studies of angina. Fifteen studies employed an intention-to-treat analysis, of which only seven specified a method to accommodate missing data. Review of these studies identified deficiencies in both reporting and methodology. The review's findings suggest areas for improving the design of future studies and increasing transparency of reporting. PERSPECTIVE: This article presents a systematic review of research methods and reporting quality of randomized clinical trials of SCS for the treatment of various pain complaints. The review identifies deficiencies in both methodology and reporting, which may inform the design of future studies and improve reporting standards.

Efficacy and safety of regorafenib compared to placebo and to post-cross-over regorafenib in advanced non-adipocytic soft tissue sarcoma

INTRODUCTION

The placebo-controlled phase-2 REGOSARC trial demonstrated the efficacy of regorafenib in patients with leiomyosarcoma, synovial sarcoma and other non-adipocytic sarcoma but not in liposarcoma. Patients initially allocated to placebo were allowed to receive regorafenib after progression. We report here an updated analysis of the trial including evaluation of regorafenib activity after cross-over.

METHODS

From June 2013 to December 2014, 139 patients were enrolled in the non-adipocytic sarcoma cohorts. Median follow-up is now 32.4 months. Benefit of regorafenib versus placebo in terms of progression-free survival (PFS) and overall survival (OS) from randomisation was estimated by hazard ratio (HR) in Cox models. In the placebo arm, intra-patient benefit of regorafenib after cross-over was evaluated by the growth modulation index (GMI) (GMI was here, for each patient, PFS after cross-over regorafenib divided by PFS with placebo). Furthermore, the activity of delayed (after cross-over) versus early (at study entry) regorafenib was evaluated by comparing PFS after cross-over to regorafenib to PFS after randomisation in the regorafenib arm.

RESULTS

PFS benefit of regorafenib as compared to placebo was confirmed with longer follow-up (HR = 0.50; 95% CI: 0.35-0.71; p < .0001). OS was not statistically significant different (HR = 0.78; 0.54-1.12; p = .18). This finding may partially be explained by the fact that 55/68 patients who progressed on placebo (81%) received cross-over Regorafenib after progression: 59% of them had a GMI ≥ 1.3 (95% CI, 45-71%). Delayed start of regorafenib was associated with a statistically non-significant shorter PFS as compared to early treatment (HR = 1.21; 0.84-1.73; p = .30) without impact on OS.

CONCLUSIONS

Observed PFS confirms that regorafenib warrants further clinical investigation in refractory non-adipocytic sarcomas.

Effect of Crossover in Oncology Clinical Trials on Evidence Levels in Early Benefit Assessment in Germany

BACKGROUND

In oncology clinical trials, crossover is used frequently but may lead to uncertainties regarding treatment effects.

OBJECTIVE

To investigate the handling of evidence from crossover trials by the European Medicines Agency (EMA) and the German Federal Joint Committee (G-BA).

METHODS

For oncology medicines with early benefit assessments before January 2015, presence of crossover, clinical data, EMA requests for additional data, and G-BA benefit ratings/evidence levels were analyzed from manufacturers' dossiers, G-BA appraisals, European Public Assessment Reports, and original publications.

RESULTS

Eleven of 21 benefit assessments included crossover trials. Significant intergroup differences (P < 0.05) in overall survival (OS) were noted in 7 of 11 trials with and 7 of 10 without crossover. For 6 of 11 medicines with crossover, these were demonstrated before crossover. Treatment effects generally worsened with increasing proportions of crossover. The EMA requested additional data more frequently if crossover was performed, particularly if no OS data were available before crossover. The G-BA granted a considerable benefit to 73% of medicines with crossover and 40% of those without. Evidence levels were intermediate for 50% and 75%, respectively. None of the medicines received the highest evidence level.

CONCLUSIONS

In G-BA appraisals, oncology medicines with crossover received better additional benefit ratings, but were assigned lower evidence levels, than those without. The five medicines with crossover after progression were assigned lower evidence levels than the six medicines with crossover after demonstration of superior OS, indicating that the way in which crossover is implemented may be one factor influencing the assignment of evidence levels by the G-BA.

Cost Effectiveness of Nivolumab in Advanced Renal Cell Carcinoma

BACKGROUND

In recent years, new drugs have been introduced for second-line treatment of advanced renal cell carcinoma (RCC). Nivolumab increases overall survival and is associated with less toxicity compared to everolimus in this setting according to the CheckMate 025 study. However, because of the high cost of nivolumab, there is a need to define its value by considering both efficacy and cost.

OBJECTIVE

To estimate the cost effectiveness of nivolumab for second-line treatment of advanced RCC from the US payer perspective.

DESIGN, SETTING, AND PARTICIPANTS

A Markov model was developed to compare the costs and effectiveness of nivolumab with those of everolimus and placebo in second-line treatment of advanced RCC. Health outcomes were measured in life-years (LYs) and quality-adjusted LYs (QALYs). Drug costs were based on 2016 Medicare reimbursement rates.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Model robustness was assessed in univariable and probabilistic sensitivity analyses. We addressed the issue of the extensive duration of immunotherapy treatment among long-term survivors, which may or may not be approved by payers.

RESULTS AND LIMITATIONS

The total mean cost per patient was $101 070 for nivolumab and $50 935 for everolimus. Nivolumab generated a gain of 0.24 LYs (0.34 QALYs) compared to everolimus. The incremental cost-effectiveness ratio (ICER) for nivolumab was $146 532/QALY versus everolimus and $226 197/QALY versus placebo. Limiting the maximal treatment duration of nivolumab to 2 yr reduced the ICER to $121 788/QALY versus everolimus. The analysis is limited by data availability and our assumptions.

CONCLUSIONS

Our analysis established that with a willingness-to-pay threshold of $100 000 to $150 000 per QALY, nivolumab is estimated to be cost-effective versus everolimus, but not cost-effective versus placebo.

PATIENT SUMMARY

We assessed the cost effectiveness of nivolumab in previously treated metastatic kidney cancer. In the USA, it would cost $146 532 to gain one quality-adjusted life-year with nivolumab versus everolimus, or $226 197 versus placebo. Nivolumab is considered cost-effective versus everolimus, but not versus placebo.

Five years of EMA-approved systemic cancer therapies for solid tumours-a comparison of two thresholds for meaningful clinical benefit

OBJECTIVE

Several societies have proposed frameworks to evaluate the benefit of oncology drugs; one prominent tool is the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS). Our objectives were to investigate the extent of European Medicines Agency (EMA)-approved cancer drugs that meet the threshold for 'meaningful clinical benefit' (MCB), defined by the framework, and determine the change in the distribution of grades when an adapted version that addresses the scale's limitations is applied.

METHODS

We identified cancer drugs approved by the EMA (2011-2016). We previously proposed adaptations to the ESMO-MCBS addressing its main limitations, including the use of the lower limit of the 95% confidence interval in assessing the hazard ratio. To assess the MCB, both the original and adapted ESMO-MCBS were applied to the respective approval studies.

RESULTS

In total, we identified 70 approval studies for 38 solid cancer drugs. 21% of therapies met the MCB threshold by the original ESMO-MCBS criteria. In contrast, only 11% of therapies met the threshold for MCB when the adapted ESMO-MCBS was applied. Thus 89% and 79% of therapies did not meet the MCB threshold in the adapted and original ESMO-MCBS, respectively.

CONCLUSIONS

In most of the cancer drugs, the MCB threshold is not met at the time of approval when measured using both ESMO-MCBS scales. Since approval status does not translate into a MCB, stakeholders and decision makers should focus on the benefit/risk ratio of anticancer drugs to assure an appropriate allocation of resources in health care systems.

TREATMENT SWITCHING IN CANCER TRIALS: ISSUES AND PROPOSALS

OBJECTIVES

Treatment switching occurs when patients in a randomized clinical trial switch from the treatment initially assigned to them to another treatment, typically from the control to experimental treatment. This study discusses the issues this raises and possible approaches to addressing them in trials of cancer drugs.

METHODS

Stakeholders from around the world were invited to a 1.5-day Workshop in Adelaide, Australia. This study attempts to capture the key points from the discussion and the perspectives of the various stakeholder groups, but is not a formal consensus statement.

RESULTS

Treatment switching raises challenging ethical issues with arguments for and against allowing it. It is increasingly common in cancer drug trials and presents challenges for the interpretation of results by regulators, clinicians, patients, and payers. Proposals are offered for good practice in the design, management, and analysis of trials and wider development programs for cancer drugs in which treatment switching has occurred or is likely to. Recommendations are also offered for further action to improve understanding of the importance and challenges of treatment switching and to promote agreement between key stakeholders on guidelines and other steps to address these challenges.

CONCLUSIONS

The handling of treatment switching in trials is of concern to all stakeholders. On the basis of the discussions at the Adelaide International Workshop, there would appear to be common ground on approaches to addressing treatment switching in cancer trials and scope for the development of formal guidelines to inform the work of regulators, payers, industry, trial designers and other stakeholders.

Crossover Designs in Nutrition and Dietetics Research

This article is the 12th installment in a statistical series exploring the importance of research design, epidemiologic methods, and statistical analysis as applied to nutrition and dietetics research. The purpose of this series is to assist registered dietitian nutritionists in interpreting nutrition research and aid nutrition researchers in applying scientific principles to produce high-quality nutrition research. This article focuses on the use of crossover designs in nutrition and dietetics research. The purpose is to distinguish the crossover design from the randomized clinical trial, define important terms, illustrate a 2×2 crossover design, discuss potential confounding variables in the crossover design, describe the analysis and interpretation of crossover data, present sample size considerations, provide examples of the use of the crossover design in nutrition and dietetics, and discuss additional considerations when the independent variable has more than two levels.

Standard of care in immunotherapy trials: Challenges and considerations

The success of immunotherapeutics over the past decade has fundamentally altered the therapeutic landscape in melanoma and non-small cell lung (NSCLC) cancer care. Multiple clinical trials have confirmed significant improvements in survival with a variety of immunotherapeutic strategies. The careful and appropriate selection of standard of care (SOC) therapies is key to the successful design and interpretation of these trials. To date immunotherapeutic trials have used best supportive care, matched placebo, chemotherapy, targeted therapy or, more recently, established immunotherapeutics in melanoma clinical trials as SOCs. Each of these SOC choices has a fundamental impact on the selection and validity of response assessment criteria and clinical endpoints. As yet there is no established approach, thus new data must be interpreted with an understanding of the limitations of the current paradigm. Additionally, the pace of development has mandated the use of novel clinical trial designs, answering multiple therapeutic questions simultaneously and designed to expedite regulatory approval. This review addresses the most important challenges in the selection of SOC in immunotherapeutic trials and the current and future challenges in trial design.

Strength of Validation for Surrogate End Points Used in the US Food and Drug Administration's Approval of Oncology Drugs

OBJECTIVE

To determine the strength of the surrogate-survival correlation for cancer drug approvals based on a surrogate.

PARTICIPANTS AND METHODS

We performed a retrospective study of the US Food and Drug Administration (FDA) database, with focused searches of MEDLINE and Google Scholar. Among cancer drugs approved based on a surrogate end point, we examined previous publications assessing the strength of the surrogate-survival correlation. Specifically, we identified the percentage of surrogate approvals lacking any formal analysis of the strength of the surrogate-survival correlation, and when conducted, the strength of such correlations.

RESULTS

Between January 1, 2009, and December 31, 2014, the FDA approved marketing applications for 55 indications based on a surrogate, of which 25 were accelerated approvals and 30 were traditional approvals. We could not find any formal analyses of the strength of the surrogate-survival correlation in 14 out of 25 accelerated approvals (56%) and 11 out of 30 traditional approvals (37%). For accelerated approvals, just 4 approvals (16%) were made where a level 1 analysis (the most robust way to validate a surrogate) had been performed, with all 4 studies reporting low correlation (r≤0.7). For traditional approvals, a level 1 analysis had been performed for 15 approvals (50%): 8 (53%) reported low correlation (r≤0.7), 4 (27%) medium correlation (r>0.7 to r<0.85), and 3 (20%) high correlation (r≥0.85) with survival.

CONCLUSIONS

The use of surrogate end points for drug approval often lacks formal empirical verification of the strength of the surrogate-survival association.

[Challenges for clinical trials in oncology within the scope of early benefit assessment of drugs]

Until May 31, 2015 the German Institute for Quality and Efficiency in Health Care (IQWiG) conducted 108 assessments for various diseases on the basis of 103 dossiers within the scope of the early benefit assessment of drugs pursuant to the Act on the Reform of the Market for Medicinal Products (AMNOG). 29 of these assessments (28 dossiers) referred to advanced stages of oncologic (including neoplastic-hematologic) diseases. In 21 of these 29 assessments (72%), IQWiG found an added benefit for at least one subpopulation or subgroup, compared to 33% with non-oncologic diseases. For oncologic diseases, the extent of benefit was classified as "major" in six assessments (21%), compared to 5% for non-oncologic disorders. In contrast, the conclusions of the oncologic studies were less certain: only one assessment provided proof (of an added benefit); for non-oncologic diseases, this was the case in eight assessments. A distinctive methodological feature of the available oncologic studies is that, as a rule, treatment switching was planned in the event of progression (normally on the basis of imaging or laboratory findings) and that shortly afterwards the follow-up of important endpoints (adverse events and patient-reported outcomes) was normally discontinued. In particular, the pre-specified option in the study protocol allowing the control group to switch treatment to the experimental intervention after progression ("protocol-permitted treatment switches") makes it extremely difficult to interpret the results beyond the outcome "progression" (or progression-free survival). This treatment switching is mostly justified by reference to ethical necessity. This, however, alleges that the experimental intervention (i. e., the new drug) is superior to the control intervention, which means that circular reasoning is unavoidable. But despite this, oncologic studies are better than their reputation. Hence, so far the results of the early benefit assessment of new drugs (regarding the existence and extent of an added benefit) are clearly better than expected. In this context, the IQWiG methods have not been shown to be extremely conservative. On the contrary: in all cases where IQWiG rated the extent of benefit as "major" for the oncologic indications, the Federal Joint Committee (G-BA) has so far not shared this assessment, and instead rated the extent of benefit to be smaller.

A standardised, generic, validated approach to stratify the magnitude of clinical benefit that can be anticipated from anti-cancer therapies: the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS)

The value of any new therapeutic strategy or treatment is determined by the magnitude of its clinical benefit balanced against its cost. Evidence for clinical benefit from new treatment options is derived from clinical research, in particular phase III randomised trials, which generate unbiased data regarding the efficacy, benefit and safety of new therapeutic approaches. To date, there is no standard tool for grading the magnitude of clinical benefit of cancer therapies, which may range from trivial (median progression-free survival advantage of only a few weeks) to substantial (improved long-term survival). Indeed, in the absence of a standardised approach for grading the magnitude of clinical benefit, conclusions and recommendations derived from studies are often hotly disputed and very modest incremental advances have often been presented, discussed and promoted as major advances or 'breakthroughs'. Recognising the importance of presenting clear and unbiased statements regarding the magnitude of the clinical benefit from new therapeutic approaches derived from high-quality clinical trials, the European Society for Medical Oncology (ESMO) has developed a validated and reproducible tool to assess the magnitude of clinical benefit for cancer medicines, the ESMO Magnitude of Clinical Benefit Scale (ESMO-MCBS). This tool uses a rational, structured and consistent approach to derive a relative ranking of the magnitude of clinically meaningful benefit that can be expected from a new anti-cancer treatment. The ESMO-MCBS is an important first step to the critical public policy issue of value in cancer care, helping to frame the appropriate use of limited public and personal resources to deliver cost-effective and affordable cancer care. The ESMO-MCBS will be a dynamic tool and its criteria will be revised on a regular basis.