A systematic review of trial-level meta-analyses measuring the strength of association between surrogate end-points and overall survival in oncology

FDA Acceptance of Surrogate End Points for Cancer Drug Approval: 1992-2019

This retrospective review assesses the frequency of surrogate measures used for the first time vs subsequent times in a cancer setting and the surrogate’s strength of correlation with patient-centered outcomes.

An overview of platform trials with a checklist for clinical readers

OBJECTIVES

The objective of the study was to outline key considerations for general clinical readers when critically evaluating publications on platform trials and for researchers when designing these types of clinical trials.

STUDY DESIGN AND SETTING

In this review, we describe key concepts of platform trials with case study discussion of two hallmark platform trials in STAMPEDE and I-SPY2. We provide reader's guide to platform trials with a critical appraisal checklist.

RESULTS

Platform trials offer flexibilities of dropping ineffective arms early based on interim data and introducing new arms into the trial. For platform trials, it is important to consider how interventions are compared and evaluated throughout and how new interventions are introduced. For intervention comparisons, it is important to consider what the primary analysis is, what and how many interventions are active simultaneously, and allocation between different arms. Interim evaluation considerations should include the number and timing of interim evaluations and outcomes and statistical rules used to drop interventions. New interventions are usually introduced based on scientific merits, so consideration of these merits is important, together with the timing and mechanisms in which new interventions are added.

CONCLUSION

More efforts are needed to improve the scientific literacy of platform trials. Our review provides an overview of the important concepts of platform trials.

Reprioritizing Risk and Benefit: The Future of Study Design in Early-Phase Cancer Research

The scientific purpose of phase I trials is to determine the maximum tolerated dose and/or optimal biological dose of experimental agents. Yet most participants in phase I oncology trials enroll hoping for direct medical benefit. The most common phase I trial designs use low starting doses and escalate cautiously in a "risk-escalation" model focused on minimizing risk for each participant. This approach ensures that a proportion of subjects will likely not receive any benefit, even if the intervention proves to be successful at appropriate doses. In this article, we propose that trial designs should employ dosing strategies that increase chances of providing benefit if the investigational agent should prove to be successful while limiting risk to reasonable levels. We then describe how adaptive trial designs can facilitate refined dose optimization based on both therapeutic benefit and toxicity, which can simultaneously decrease the risk of harm while increasing the chances of benefit.

A Systematic Review and Meta-Analysis of Bevacizumab in First-Line Metastatic Breast Cancer: Lessons for Research and Regulatory Enterprises

BACKGROUND

The US Food and Drug Administration's accelerated approval and later withdrawal of bevacizumab in patients with metastatic breast cancer (mBC) is a seminal case for ongoing debates about the validity of using progression-free survival (PFS) as a surrogate measure for overall survival (OS) in cancer drug approvals. We systematically reviewed and meta-analyzed the evidence around bevacizumab's regulatory approval and withdrawal in mBC.

METHODS

We searched for all published phase II or III clinical trials testing bevacizumab as a first-line therapy for patients with mBC. Data were extracted on trial demographics, interventions, and outcomes. Descriptive analysis was stratified by whether the trial was initiated before, during, or after the accelerated approval. We used a cumulative random-effects meta-analysis to assess the evolution of evidence of the effect of bevacizumab on PFS and OS. We estimated the association between the trial-level PFS and OS effect using a nonlinear mixed-regression model.

RESULTS

Fifty-two studies were included. Trial activity dramatically dropped after the accelerated approval was withdrawn. Eight clinical trials reported hazard ratios (hazard ratios) and were meta-analyzed. The cumulative hazard ratio for PFS was 0.72 (95% CI = 0.65 to 0.79), and the cumulative hazard ratio for OS was 0.90 (95% CI = 0.80 to 1.01). The regression model showed a statistically nonsignificant association between PFS benefit and OS benefit (β = 0.43, SE = 0.81).

CONCLUSION

The US Food and Drug Administration's decision-making in this case was consistent with the evolving state of evidence. However, the fact that seven clinical trials are insufficient to conclude validity (or lack thereof) for a trial-level surrogate suggests that it would be more efficient to conduct trials using the more clinically meaningful endpoints.

Evaluating the evidence behind the surrogate measures included in the FDA's table of surrogate endpoints as supporting approval of cancer drugs

BACKGROUND

In July 2018, the FDA first published a table listing all surrogate measures that it has used, and may accept for future use, in regulatory approval. However, the strength of surrogacy for those measures was not formally assessed. Using the case example of breast cancer, we aimed to evaluate the strength of correlation of surrogate measures listed in the FDA's Table with overall survival.

METHODS

This cross-sectional study of the FDA's Table of Surrogate Endpoints was conducted in May 2019. All surrogate measures listed in the FDA table as appropriate for accelerated or regular approval for breast cancer were extracted. We identified studies evaluating the correlation of treatment benefit in the surrogate with treatment benefit in overall survival and extracted results from the correlation analysis.

FINDINGS

Five surrogate endpoints were listed for breast cancer in the FDA website: pathological complete response rates (pCR), event-free survival (EFS), disease-free survival (DFS), objective response rates (ORR), and progression-free survival (PFS), of which pCR was listed as appropriate only for accelerated approval, while the rest were considered appropriate for accelerated or regular approval. No correlation study evaluated the correlation of treatment effects on EFS with that on OS. The results from correlation studies evaluating pCR, DFS, ORR, and PFS suggest that the treatment effects on none of these surrogate measures were strongly correlated with treatment effects on OS (r<0.85 or R²  < 0.7, except for DFS in HER2 positive early breast cancer (R²  = 0.75).

INTERPRETATION

Using breast cancer as an example, we evaluated the underlying evidence for the surrogate endpoints for solid tumors listed in the FDA's Table of Surrogate Endpoints and found weak or missing correlations of treatment effects on these surrogates with treatment effects on OS . Surrogate measures should be predictive of clinical benefit to be useful in supporting regular FDA approval.

FUNDING

Work on this project was funded by the Arnold Ventures. Dr. Kesselheim is also supported by the Harvard-MIT Center for Regulatory Science. The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Generating comparative evidence on new drugs and devices after approval

Certain limitations of evidence available on drugs and devices at the time of market approval often persist in the post-marketing period. Often, post-marketing research landscape is fragmented. When regulatory agencies require pharmaceutical and device manufacturers to conduct studies in the post-marketing period, these studies might remain incomplete many years after approval. Even when completed, many post-marketing studies lack meaningful active comparators, have observational designs, and might not collect patient-relevant outcomes. Regulators, in collaboration with the industry and patients, ought to ensure that the key questions unanswered at the time of drug and device approval are resolved in a timely fashion during the post-marketing phase. We propose a set of seven key guiding principles that we believe will provide the necessary incentives for pharmaceutical and device manufacturers to generate comparative data in the post-marketing period. First, regulators (for drugs and devices), notified bodies (for devices in Europe), health technology assessment organisations, and payers should develop customised evidence generation plans, ensuring that future post-approval studies address any limitations of the data available at the time of market entry impacting the benefit-risk profiles of drugs and devices. Second, post-marketing studies should be designed hierarchically: priority should be given to efforts aimed at evaluating a product's net clinical benefit in randomised trials compared with current known effective therapy, whenever possible, to address common decisional dilemmas. Third, post-marketing studies should incorporate active comparators as appropriate. Fourth, use of non-randomised studies for the evaluation of clinical benefit in the post-marketing period should be limited to instances when the magnitude of effect is deemed to be large or when it is possible to reasonably infer the comparative benefits or risks in settings, in which doing a randomised trial is not feasible. Fifth, efficiency of randomised trials should be improved by streamlining patient recruitment and data collection through innovative design elements. Sixth, governments should directly support and facilitate the production of comparative post-marketing data by investing in the development of collaborative research networks and data systems that reduce the complexity, cost, and waste of rigorous post-marketing research efforts. Last, financial incentives and penalties should be developed or more actively reinforced.

Association Between the Use of Surrogate Measures in Pivotal Trials and Health Technology Assessment Decisions: A Retrospective Analysis of NICE and CADTH Reviews of Cancer Drugs

OBJECTIVE

To assess whether using surrogate versus patient-relevant endpoints in pivotal trials of cancer drugs was associated with health technology assessment recommendations in England (National Institute for Health and Care Excellence [NICE]) and Canada (Canadian Agency for Drugs and Technologies in Health [CADTH]).

METHODS

Cancer drug approvals from 2012 to 2016 were categorized by demonstrating benefit on overall survival (OS), progression-free survival, disease response, or having no comparator. Approvals were analyzed by benefit category and health technology assessment recommendation. The association between benefit (surrogate vs OS) and recommending a drug was examined using descriptive statistics and linear probability models controlling for unmet need, orphan designation, and cost-effectiveness.

RESULTS

Of 42 cancer indications that NICE recommended, 15 (36%) demonstrated OS benefit. Cancer indications with OS benefit were less likely to receive a recommendation from NICE than those without (P = .04). In linear probability models, availability of OS benefit was no longer associated with a recommendation from NICE (P = .32). Cost-effective cancer drugs had a 55.6% (95% CI: 38.9%-72.3%) higher probability of receiving a recommendation from NICE than those that were not. In Canada, 15 of 37 (41%) cancer indications that were recommended showed OS benefit. There was no detectable association between surrogate measures and CADTH recommendations based on descriptive statistics (P = .62) or in linear probability models (P = .73).

CONCLUSION

When cost-effectiveness was considered, pivotal trial endpoints were not associated with NICE recommendations. Pivotal trial endpoints, unmet need, orphan status, and cost-effectiveness did not explain CADTH recommendations.

Magnitude of advantage in tumor response contributes to a better correlation between treatment effects on overall survival and progression-free survival: a literature-based meta-analysis of clinical trials in patients with metastatic colorectal cancer

BACKGROUND

Although it is suggested that the endpoints originated from the concept of tumor shrinkage dynamics, such as early tumor shrinkage and depth of response, are strongly associated with overall survival (OS) in patients with metastatic colorectal cancer (mCRC), they are yet to be validated as a single surrogate endpoint of OS by themselves. This study aimed to investigate the impact of advantage in tumor response on the correlation between treatment effects on progression-free survival (PFS) and OS in mCRC patients.

METHODS

Based on an electronic search, we identified randomized controlled trials of first-line therapy for mCRC. The impact of advantage in objective response rate (ORR) on the correlation between treatment effects on PFS and OS was evaluated based on Spearman correlation coefficients (r_s).

RESULTS

Forty-seven trials with a total of 24,018 patients were identified. The hazard ratio for PFS showed a relatively higher correlation with that for OS (r_s = 0.63) when the trials were limited to those that demonstrated a larger difference in ORR, compared to the case for trials that demonstrated a smaller difference (r_s = 0.32). This tendency was also observed in the subgroup analysis stratified by the types of treatment agents (targeted or non-targeted).

CONCLUSIONS

The magnitude of advantage in tumor response was suggested to contribute to a better prediction of OS benefit based on PFS in patients with mCRC. The accuracy of OS estimation in mCRC is expected to be improved by considering the degree of tumor shrinkage in conjunction with PFS.

U.S. Food and Drug Administration anticancer drug approval trends from 2016 to 2018 for lung, colorectal, breast, and prostate cancer

Objective

This paper aims to describe the clinical and regulatory aspects of new drugs and indications that were approved for lung, breast, prostate, and colorectal cancer, from 2016 to 2018, in order to provide health technology assessment trends in oncology.

Methods

Data were collected from the US Food and Drug Administration (FDA) online database for new medications and indications approved for the above-mentioned types of cancer. Data regarding clinical study characteristics and regulatory information were collected.

Results

From 2016 to 2018, 53 percent of the FDA approvals of new drugs and indications for the most incident cancers were for oral protein kinase inhibitor monotherapy for advanced lung cancer. Since 2018, four drugs were approved as tumor-agnostic therapies. A biomarker was included in 72 percent of indications, and 58 percent of approvals were for targeted therapies, potentially heralding an end to research into conventional cytotoxic agents. A special designation for faster approval was granted in 78 percent of new approvals. The majority of the studies were open label randomized controlled trials (RCTs) (44 percent), followed by blind RCTs, single-arm clinical trials, and cohort studies. Only 14 percent of studies used overall survival as the primary end point; the vast majority used surrogate end points, and did not use patient-important outcomes. Three biosimilars were approved in the period.

Conclusion

Advanced lung cancer therapy, mainly targeted drugs, accounted for 53 percent of approvals. Special designations for faster approval were used in 78 percent of FDA approvals, and four drugs were approved for tumor-agnostic treatment—a new form of approval.

Design characteristics, risk of bias, and reporting of randomised controlled trials supporting approvals of cancer drugs by European Medicines Agency, 2014-16: cross sectional analysis

OBJECTIVE

To examine the design characteristics, risk of bias, and reporting adequacy of pivotal randomised controlled trials of cancer drugs approved by the European Medicines Agency (EMA).

DESIGN

Cross sectional analysis.

SETTING

European regulatory documents, clinical trial registry records, protocols, journal publications, and supplementary appendices.

ELIGIBILITY CRITERIA

Pivotal randomised controlled trials of new cancer drugs approved by the EMA between 2014 and 2016.

MAIN OUTCOME MEASURES

Study design characteristics (randomisation, comparators, and endpoints); risk of bias using the revised Cochrane tool (bias arising from the randomisation process, deviations from intended interventions, missing outcome data, measurement of the outcome, and selection of the reported result); and reporting adequacy (completeness and consistency of information in trial protocols, publications, supplementary appendices, clinical trial registry records, and regulatory documents).

RESULTS

Between 2014 and 2016, the EMA approved 32 new cancer drugs on the basis of 54 pivotal studies. Of these, 41 (76%) were randomised controlled trials and 13 (24%) were either non-randomised studies or single arm studies. 39/41 randomised controlled trials had available publications and were included in our study. Only 10 randomised controlled trials (26%) measured overall survival as either a primary or coprimary endpoint, with the remaining trials evaluating surrogate measures such as progression free survival and response rates. Overall, 19 randomised controlled trials (49%) were judged to be at high risk of bias for their primary outcome. Concerns about missing outcome data (n=10) and measurement of the outcome (n=7) were the most common domains leading to high risk of bias judgments. Fewer randomised controlled trials that evaluated overall survival as the primary endpoint were at high risk of bias than those that evaluated surrogate efficacy endpoints (2/10 (20%) v 16/29 (55%), respectively). When information available in regulatory documents and the scientific literature was considered separately, overall risk of bias judgments differed for eight randomised controlled trials (21%), which reflects reporting inadequacies in both sources of information. Regulators identified additional deficits beyond the domains captured in risk of bias assessments for 10 drugs (31%). These deficits included magnitude of clinical benefit, inappropriate comparators, and non-preferred study endpoints, which were not disclosed as limitations in scientific publications.

CONCLUSIONS

Most pivotal studies forming the basis of EMA approval of new cancer drugs between 2014 and 2016 were randomised controlled trials. However, almost half of these were judged to be at high risk of bias based on their design, conduct, or analysis, some of which might be unavoidable because of the complexity of cancer trials. Regulatory documents and the scientific literature had gaps in their reporting. Journal publications did not acknowledge the key limitations of the available evidence identified in regulatory documents.

Challenges and Opportunities for Biomarker Validation

Biomarkers can be powerful tools to guide diagnosis, treatment, and research. However, prudent use of bio-markers requires formal validation efforts. Although the data needed for biomarker validation has traditionally been hard to access, new research initiatives can ease this process.

The use of validated and nonvalidated surrogate endpoints in two European Medicines Agency expedited approval pathways: A cross-sectional study of products authorised 2011-2018

BACKGROUND

In situations of unmet medical need or in the interests of public health, expedited approval pathways, including conditional marketing authorisation (CMA) and accelerated assessment (AA), speed up European Medicines Agency (EMA) marketing authorisation recommendations for medicinal products. CMAs are based on incomplete benefit-risk assessment data and authorisation remains conditional until regulator-imposed confirmatory postmarketing measures are fulfilled. For products undergoing AA, complete safety and efficacy data should be available, and postauthorisation measures may include only standard requirements of risk management and pharmacovigilance plans. In the pivotal trials supporting products assessed by expedited pathways, surrogate endpoints reduce drug development time compared with waiting for the intended clinical outcomes. Whether surrogate endpoints supporting products authorised through CMA and AA pathways reliably predict clinical benefits of therapy has not been studied systematically. Our objectives were to determine the extent to which surrogate endpoints are used and to assess whether their validity had been confirmed according to published hierarchies.

METHODS AND FINDINGS

We used European Public Assessment Reports (EPARs) to identify the primary endpoints in the pivotal trials supporting products authorised through CMA or AA pathways during January 1, 2011 to December 31, 2018. We excluded products that were vaccines, topical, reversal, or bleeding prophylactic agents or withdrawn within the study time frame. Where pivotal trials reported surrogate endpoints, we conducted PubMed searches for evidence of validity for predicting clinical outcomes. We used 2 published hierarchies to assess validity level. Surrogates with randomised controlled trials supporting the surrogate-clinical outcome relationship were rated as 'validated'. Fifty-one products met the inclusion criteria; 26 underwent CMAs, and 25 underwent AAs. Overall, 26 products were for oncology indications, 10 for infections, 8 for genetic disorders, and 7 for other systems disorders. Five products (10%), all AAs, were authorised based on pivotal trials reporting clinical outcomes, and 46 (90%) were authorised based on surrogate endpoints. No studies were identified that validated the surrogate endpoints. Among a total of 49 products with surrogate endpoints reported, most were rated according to the published hierarchies as being 'reasonably likely' (n = 30; 61%) or of having 'biological plausibility' (n = 46; 94%) to predict clinical outcomes. EPARs did not consistently explain the nature of the pivotal trial endpoints supporting authorisations, whether surrogate endpoints were validated or not, or describe the endpoints to be reported in the confirmatory postmarketing studies. Our study has limitations: we may have overlooked relevant validation studies; the findings apply to 2 expedited pathways and may not be generalisable to products authorised through the standard assessment pathway.

CONCLUSIONS

The pivotal trial evidence supporting marketing authorisations for products granted CMA or AA was based dominantly on nonvalidated surrogate endpoints. EPARs and summary product characteristic documents, including patient information leaflets, need to state consistently the nature and limitations of endpoints in pivotal trials supporting expedited authorisations so that prescribers and patients appreciate shortcomings in the evidence about actual clinical benefit. For products supported by nonvalidated surrogate endpoints, postauthorisation measures to confirm clinical benefit need to be imposed by the regulator on the marketing authorisation holders.

Umbrella and basket trials in oncology: ethical challenges

BACKGROUND

Novel precision oncology trial designs, such as basket and umbrella trials, are designed to test new anticancer agents in more effective and affordable ways. However, they present some ethical concerns referred to scientific validity, risk-benefit balance and informed consent. Our aim is to discuss these issues in basket and umbrella trials, giving examples of two ongoing cancer trials: NCI-MATCH (National Cancer Institute - Molecular Analysis for Therapy Choice) and Lung-MAP (Lung Cancer Master Protocol) study.

MAIN BODY

We discuss three ethical requirements for clinical trials which may be challenged in basket and umbrella trial designs. Firstly, we consider scientific validity. Thanks to the new trial designs, patients with rare malignancies have the opportunity to be enrolled and benefit from the trial, but due to insufficient accrual, the trial may generate clinically insignificant findings. Inadequate sample size in study arms and the use of surrogate endpoints may result in a drug approval without confirmed efficacy. Moreover, complexity, limited quality and availability of tumor samples may not only introduce bias and result in unreliable and unrepresentative findings, but also can potentially harm patients and assign them to an inappropriate therapy arm. Secondly, we refer to benefits and risks. Novel clinical trials can gain important knowledge on the variety of tumors, which can be used in future trials to develop effective therapies. However, they offer limited direct benefits to patients. All potential participants must wait about 2 weeks for the results of the genetic screening, which may be stressful and produce anxiety. The enrollment of patients whose tumors harbor multiple mutations in treatments matching a single mutation may be controversial. As to informed consent - the third requirement we discuss, the excessive use of phrases like "personalized medicine", "tailored therapy" or "precision oncology" might be misleading and cause personal convictions that the study protocol is designed to fulfill the individual health-related needs of participants.

CONCLUSIONS

We suggest that further approaches should be implemented to enhance scientific validity, reduce misunderstandings and risks, thus maximizing the benefits to society and to trial participants.

Assessing the Justification, Funding, Success, and Survival Outcomes of Randomized Noninferiority Trials of Cancer Drugs: A Systematic Review and Pooled Analysis

IMPORTANCE

Noninferiority trials test whether a new intervention is not worse than the comparator by a given margin.

OBJECTIVES

To study the characteristics of published randomized noninferiority trials in oncology with overall survival as an end point, to assess the association of justification and success in achieving noninferiority with the funding of these trials, and to evaluate the association of such trials with patient survival.

DATA SOURCES

A systematic search of PubMed and Google Scholar databases was conducted in March 2018, with no date restrictions.

STUDY SELECTION

Randomized noninferiority trials of cancer drug therapies with overall survival as an end point were included. Trials of decision support, supportive care, and nondrug treatment in both arms were excluded.

DATA EXTRACTION AND SYNTHESIS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for meta-epidemiological studies. Studies were screened for eligibility criteria, and data on criteria for noninferiority, funding, success (achieving noninferiority), and hazard ratios with confidence intervals for overall survival were extracted. Hazard ratios for overall survival were pooled across trials using a random-effects model.

MAIN OUTCOMES AND MEASURES

Associations of the justification for using a noninferiority design and success in achieving noninferiority with the source of funding were assessed. Overall pooled hazard ratios and confidence intervals for overall survival were calculated.

RESULTS

Among 74 noninferiority trials of cancer drug therapies, 23 (31%; enrolling 21 437 patients) used overall survival as the primary end point. The noninferiority margins for the hazard ratio of overall survival ranged from 1.08 to 1.33. Noninferiority design was justified in 14 trials (61%) but not in 9 (39%). Overall, 18 trials (78%) concluded with a finding of noninferiority. Industry funding was associated with lack of justification for noninferiority design (P = .02, assessed using the Fisher exact test) but not with success in proving noninferiority (P = .80, assessed using the Fisher exact test). When the hazard ratios across the trials were pooled, there was no beneficial or detrimental association with overall survival, with a pooled hazard ratio of 0.97 (95% CI, 0.92-1.02).

CONCLUSIONS AND RELEVANCE

The findings suggest that a substantial fraction of noninferiority trials in oncology, most of which are industry funded, lack justification for such a design. Greater attention to the use of noninferiority designs in randomized clinical trials of cancer drugs from local and national regulators is warranted.

An Overview of Cancer Drugs Approved by the US Food and Drug Administration Based on the Surrogate End Point of Response Rate

IMPORTANCE

Approximately one-third of cancer drugs are approved based on response rate (RR)-the percentage of patients whose tumors shrink beyond an arbitrary threshold-typically assessed in a single-arm study.

OBJECTIVE

To characterize RR end points used by the US Food and Drug Administration (FDA) for cancer drug approval.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review of FDA-approved drug indications in oncology from 2006 to 2018.

EXPOSURES

Data related to cancer type, line of therapy (first-line, second-line, or third-or-later-line treatment for advanced/metastatic disease), type of FDA approval pathway, trial design, sample size, and level of innovation were extracted.

MAIN OUTCOMES AND MEASURES

The primary outcome was the RR used as the basis for FDA approval. The secondary outcome was rate of complete response.

RESULTS

Eighty-five indications for 59 cancer drugs were identified, 32 (38%) received regular approval, and 53 (62%) were granted accelerated approval. Twenty-nine (55%) accelerated approvals were later converted to regular approval. Of these, 6 (21%) approvals showed overall survival benefit, 16 (55%) later established progression-free survival benefit, and 7 (24%) continued to use RR but gained regular approval. The median RR among the 85 indications was 41% (interquartile range [IQR], 27%-58%). Among them, 14 of 85 (16%) had an RR less than 20%, 28 of 85 (33%) had an RR less than 30%, and 40 of 85 (47%) had an RR less than 40%. The median complete RR for 81 participants was 6% (IQR, 2%-22%). The median sample size among studies leading to approval was 117 (IQR, 76-182; range, 18-1052 participants). Drugs with accelerated approval pending confirmatory data had lower RR compared with drugs that have completed most postmarketing efficacy requirements (median, 28%; IQR, 15%-50% vs median, 42%; IQR, 31%-58%; P = .02).

CONCLUSIONS AND RELEVANCE

Many cancer drugs approved on the basis of response rate offer numerically low or modest response rates. Most premarket studies accrue more than 100 patients. Some of these drugs could potentially be tested in premarket randomized clinical trials measuring directly end points that demonstrate clinical benefit.

Endpoint surrogacy in oncological randomized controlled trials with immunotherapies: a systematic review of trial-level and arm-level meta-analyses

Few cancer drugs or their indications achieved survival benefit in subsequent trials during postmarket period after approval based on surrogate endpoints. This causes a concern of using surrogate endpoints instead of overall survival (OS) as the primary endpoint for trial design, implementation and regulation approval. We conducted a systematic review to summarize the findings from published meta-analyses which have evaluated endpoint surrogacy for OS in oncological randomized controlled trials (RCTs) with immunotherapies. After searching articles indexed in PubMed prior to 24 February 2019, we identified a total of 11 meta-analyses for advanced multiple tumors, non-small cell lung cancer (NSCLC), urothelial carcinoma, renal cell carcinoma, melanoma; most (91%; 10/11) focused on immune checkpoint inhibitors. Although the evaluation criteria adopted by these meta-analyses for validating endpoint surrogacy were not consistent (ranging from R² ≥0.60 to R² ≥0.80), the results were consistent. Few studies show an association between OS and progression-free survival (PFS)/objective response rate (ORR) that met the lowest evaluation criteria (R² ≥0.60), based on treatment effects (8%; 2/26 indications) or absolute results from experimental arm (0%; 0/11 indications). However, the association between OS and 1-year survival rate met the lowest criteria based on both the trial-level results (4/4 indications) and the arm-level results (5/5 indications). In lieu of this finding, we are supportive of an alternative endpoint, e.g., 1-year survival rate, rather than the more conventional choices PFS and ORR, as promising surrogate endpoint for OS in immunotherapy RCTs. We encourage further investigation on endpoint surrogacy based on the same or different settings, especially an assessment on survival rate at milestone time (e.g., 1-year), which has been demonstrated valuable for predicting OS in meta-analyses.

Estimation of Study Time Reduction Using Surrogate End Points Rather Than Overall Survival in Oncology Clinical Trials

IMPORTANCE

Surrogate end points in oncology trade the advantage of reducing the time needed to conduct clinical trials for the disadvantage of greater uncertainty regarding the treatment effect on patient-centered end points, such as overall survival (OS) and quality of life.

OBJECTIVE

To quantify the amount of time saved through the acceptance of surrogate end points, including response rate (RR) and progression-free survival (PFS).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective study of US Food and Drug Administration (FDA) oncology approvals and their drug registration trials based on actual publication analyzed the original and updated clinical trials data that led to FDA-approved drug indications in oncology from 2006 to 2017 by using existing publications, conference abstracts, and package inserts from the FDA. Data related to cancer type, line of therapy (first-line, second-line, and third- or later-line treatment of advanced or metastatic disease), FDA approval type, end point basis for approval (RR, PFS, or OS/quality of life), sample size, accrual rate, and drug RR were extracted by March 23, 2018. All data were analyzed by July 13, 2018.

MAIN OUTCOMES AND MEASURES

The main outcome was the study duration needed to complete the primary end point analysis used for each drug indication approval. This was estimated from reported enrollment dates, analysis cutoff dates, time to response, median duration of response, median PFS, and median OS.

RESULTS

In total, 188 distinct indications among 107 cancer drugs were identified. The RR was more often used for FDA approval in subsequent lines of therapy (17 of 71 drug indications [24%] in first-line therapy vs 34 of 77 drug indications [44%] in second-line therapy vs 19 of 24 drug indications [79%] in third- or later-line therapy, P < .001). Study duration for PFS (median, 31 [range, 10-104] months) was similar to that for OS (median, 33 [range, 12-117] months; P = .31), whereas study duration for RR (median, 25 [range, 11-54] months) was shorter than that for OS (P = .001). In multivariate analysis, compared with using OS, use of PFS as the end point was associated with study durations that were shorter by a mean of 11 months (95% CI, 5-17 months), and the use of RR as the end point was associated with study durations that were shorter by a mean of 19 months (95% CI, 13-25 months).

CONCLUSIONS AND RELEVANCE

From the findings of this study, an estimated 11 months appeared to be needed (ie, approximately 12% longer in the drug development cycle) to assess the OS benefit of a cancer drug. This study's findings suggest that this must be weighed against the downside of increased uncertainty of clinical benefit arising from using surrogate end points.

Highlights of the 16th St Gallen International Breast Cancer Conference, Vienna, Austria, 20-23 March 2019: personalised treatments for patients with early breast cancer

The 16th St Gallen International Breast Cancer Conference took place in Vienna for the third time, from 20–23 March 2019. More than 3000 people from all over the world were invited to take part in this important bi-annual critical review of the ‘state of the art’ in the primary care of breast cancer (BC), independent of political and industrial pressure, with the aim to integrate the most recent research data and most important developments in BC therapies since St Gallen International Breast Cancer Conference 2017, with the ultimate goal of drawing up a consensus for the current optimal treatment and prevention of BC.

This year, the St Gallen Breast Cancer Award was won by Monica Morrow (Memorial Sloan Kettering Cancer Center, USA) for her extraordinary contribution in research and practise development in the treatment of BC. She opened the session with the lecture ‘Will surgery be a part of BC treatment in the future?’ Improved systemic therapy has decreased BC mortality and increased pathologic complete response (pCR) rates after neoadjuvant chemotherapy (NACT). Improved imaging and increased screening uptake have led to detect smaller cancers. These factors have highlighted two possible scenarios to omit surgery: for patients with small low-grade ductal carcinoma in situ (DCIS) and for those who have received NACT and had a clinical and radiological complete response. However, considering that 7%–20% of `low-risk’ DCIS patients have co-existing invasive cancer at diagnosis, that surgery has become progressively less morbid and less toxic than some systemic therapies with a lower cost-effectiveness ratio, and that identification of pathologic complete response (pCR) without surgery requires more intensive imaging follow-up (more biopsies, higher cost and more anxiety for the patient), surgery still appears to be an essential treatment for BC.

The Umberto Veronesi Memorial Award went to Lesley Fallowfield (Brighton and Sussex Medical School, UK) for her important research and activity in the field of the development of patient outcome, of better communication skills and quality of life for women. In her lecture, she remarked on the importance of improving BC personalised treatments, especially through co-operation between scientists, always considering the whole woman and not just her breast disease. This award was given by Paolo Veronesi, after a moving introduction which culminated with the following words of Professor Umberto Veronesi:

‘It is not possible to take care of the people’s bodies without taking care of their mind. My duty, the duty of all doctors, is to listen and be part of the emotions of those we treat every day’.